Animals Planet

This article is about the species that is commonly kept as a pet. For the cat family, seeFelidae. For other uses, seeCat (disambiguation). "Cats" redirects here. For other uses, seeCats (disambiguation). Thecat(Felis catus) is adomesticspeciesof smallcarnivorousmammal.[1][2]It is the only domesticated species in the familyFelidaeand is often referred to as thedomestic catto distinguish it from the wild members of the family.[4]A cat can either be ahouse cat, afarm cator aferal cat; the latter ranges freely and avoids human contact.[5]Domestic cats are valued by humans for companionship and their ability to killrodents. About 60cat breedsare recognized by variouscat registries.[6] Cat Temporal range: 9,500 years ago – present Various types of cat Conservation status Domesticated Scientific classificationKingdom:AnimaliaPhylum:ChordataClass:MammaliaOrder:CarnivoraSuborder:FeliformiaFamily:FelidaeSubfamily:FelinaeGenus:FelisSpecies: F.catus[1] Binomial nameFelis catus[1] Linnaeus,1758[2] Synonyms Catus domesticusErxleben, 1777[3] F. angorensisGmelin, 1788 F. vulgarisFischer, 1829 The cat is similar inanatomyto the other felid species: it has a strong flexible body, quickreflexes, sharp teeth andretractable clawsadapted to killing small prey. Itsnight visionand sense of smell are well developed.Cat communicationincludesvocalizationslikemeowing,purring, trilling, hissing,growlingand grunting as well ascat-specific body language. Apredatorthat is most active at dawn and dusk (crepuscular), the cat is a solitary hunter but asocial species. It can hear sounds too faint or too high infrequencyfor human ears, such as those made bymiceand other small mammals.[7]Cats also secrete and perceivepheromones.[8] Female domestic cats can have kittens from spring to late autumn, with litter sizes often ranging from two to five kittens.[9]Domestic cats are bred and shown at events as registeredpedigreed cats, a hobby known ascat fancy.Population controlof cats may be effected byspayingandneutering, but their proliferation and the abandonment of pets has resulted in large numbers of feral cats worldwide, contributing to the extinction of entire bird, mammal, and reptile species.[10] It was long thought that cat domestication began inancient Egypt, wherecats were veneratedfrom around 3100 BC,[11][12]but recent advances in archaeology and genetics have shown that their domestication occurred inWestern Asiaaround 7500 BC.[13] As of 2021,there were an estimated 220 million owned and 480 million stray cats in the world.[14][15]As of 2017,the domestic cat was the second most popular pet in the United States, with 95.6 million cats owned[16][17][18]and around 42 million households own at least one cat.[19]In the United Kingdom, 26% of adults have a cat with an estimated population of 10.9 million pet cats as of 2020.[20] Contents Etymology and naming The origin of the English wordcat,Old Englishcatt, is thought to be theLate Latinwordcattus, which was first used at the beginning of the 6th century.[21]It was suggested that the word 'cattus' is derived from anEgyptianprecursor ofCopticϣⲁⲩšau, "tomcat", or its feminine form suffixed with-t.[22]The Late Latin word may be derived from anotherAfro-Asiatic[23]orNilo-Saharanlanguage. TheNubianwordkaddîska"wildcat" andNobiinkadīsare possible sources or cognates.[24]The Nubian word may be a loan fromArabicقَطّ‎qaṭṭ~قِطّqiṭṭ. It is "equally likely that the forms might derive from an ancient Germanic word, imported into Latin and thence to Greek and to Syriac and Arabic".[25]The word may be derived from Germanic and Northern European languages, and ultimately be borrowed fromUralic, cf.Northern Samigáđfi, "femalestoat", andHungarianhölgy, "lady, female stoat"; fromProto-Uralic*käďwä, "female (of a furred animal)".[26] The Englishpuss, extended aspussyandpussycat, is attested from the 16th century and may have been introduced fromDutchpoesor fromLow Germanpuuskatte, related toSwedishkattepus, orNorwegianpus,pusekatt. Similar forms exist in LithuanianpuižėandIrishpuisínorpuiscín. The etymology of this word is unknown, but it may have simplyarisen from a soundused to attract a cat.[27][28] A male cat is called atomortomcat[29](or agib,[30]if neutered). Anunspayedfemale is called aqueen,[31](or amolly,[32]if spayed), especially in a cat-breeding context. A juvenile cat is referred to as akitten. InEarly Modern English, the wordkittenwas interchangeable with the now-obsolete wordcatling.[33]A group of cats can be referred to as aclowderor aglaring.[34] Taxonomy Thescientific nameFelis catuswas proposed byCarl Linnaeusin 1758 for a domestic cat.[1][2]Felis catus domesticuswas proposed byJohann Christian Polycarp Erxlebenin 1777.[3]Felis daemonproposed byKonstantin Alekseevich Satuninin 1904 was a black cat from theTranscaucasus, later identified as a domestic cat.[35][36] In 2003, theInternational Commission on Zoological Nomenclatureruled that the domestic cat is a distinct species, namelyFelis catus.[37][38]In 2007, it was considered asubspecies,F. silvestris catus, of theEuropean wildcat(F. silvestris) following results ofphylogeneticresearch.[39][40]In 2017, the IUCN Cat Classification Taskforce followed the recommendation of the ICZN in regarding the domestic cat as a distinct species,Felis catus.[41] Evolution Main article:Cat evolution  Skulls of a wildcat (top left), a housecat (top right), and a hybrid between the two. (bottom center) The domestic cat is a member of the Felidae, afamilythat had acommon ancestorabout 10–15 million years ago.[42]ThegenusFelisdivergedfrom other Felidae around 6–7 million years ago.[43]Results ofphylogeneticresearch confirm that the wildFelisspecies evolved throughsympatricorparapatric speciation, whereas the domestic cat evolved throughartificial selection.[44]The domesticated cat and its closest wild ancestor arediploidand both possess 38chromosomes[45]and roughly 20,000 genes.[46]Theleopard cat(Prionailurus bengalensis) wastamedindependently in China around 5500 BC. This line of partially domesticated cats leaves no trace in the domestic cat populations of today.[47] Domestication See also:Evolution of the domesticated cat  A cat eating a fish under a chair, amuralin an Egyptian tomb dating to the 15th century BC The earliest known indication for thetamingof anAfrican wildcat(F. lybica) wasexcavatedclose by a humanNeolithicgrave inShillourokambos, southernCyprus, dating to about 7500–7200 BC. Since there is no evidence of native mammalianfaunaon Cyprus, the inhabitants of this Neolithic village most likely brought the cat and other wild mammals to the island from theMiddle Easternmainland.[48]Scientists therefore assume that African wildcats were attracted to early human settlements in theFertile Crescentby rodents, in particular thehouse mouse(Mus musculus), and were tamed by Neolithic farmers. Thismutualrelationship between early farmers and tamed cats lasted thousands of years. Asagricultural practicesspread, so did tame and domesticated cats.[13][6]Wildcats of Egypt contributed to the maternalgene poolof the domestic cat at a later time.[49] The earliest known evidence for the occurrence of the domestic cat inGreecedates to around 1200 BC. Greek,Phoenician,CarthaginianandEtruscantraders introduced domestic cats to southern Europe.[50]During theRoman Empirethey were introduced toCorsicaandSardiniabefore the beginning of the 1st millennium.[51]By the 5th century BC, they were familiar animals around settlements inMagna GraeciaandEtruria.[52]By the end of the Roman Empire in the 5th century, the Egyptian domestic cat lineage had arrived in aBaltic Seaport in northernGermany.[49] During domestication, cats have undergone only minor changes in anatomy and behavior, and they are still capable of surviving in the wild. Several natural behaviors and characteristics of wildcats may havepre-adaptedthem for domestication as pets. These traits include their small size, social nature, obvious body language, love of play and relatively high intelligence. CaptiveLeoparduscats may also display affectionate behavior toward humans but were not domesticated.[53]House cats often mate with feral cats,[54]producing hybrids such as theKellas catinScotland.[55]Hybridisation between domestic and other Felinae speciesis also possible.[56] Development ofcat breedsstarted in the mid 19th century.[57]An analysis of the domestic catgenomerevealed that the ancestral wildcat genome was significantly altered in the process of domestication, as specificmutationswere selected to develop cat breeds.[58]Most breeds are founded on random-bred domestic cats.Genetic diversityof these breeds varies between regions, and is lowest in purebred populations, which show more than 20 deleteriousgenetic disorders.[59] Characteristics Main article:Cat anatomy Size  Diagram of the generalanatomyof a male domestic cat The domestic cat has a smallerskulland shorter bones than theEuropean wildcat.[60]It averages about 46cm (18in) in head-to-body length and 23–25cm (9–10in) in height, with about 30cm (12in) long tails. Males are larger than females.[61]Adult domestic cats typically weigh between 4 and 5kg (9 and 11lb).[44] Skeleton Cats have sevencervical vertebrae(as do mostmammals); 13thoracic vertebrae(humans have 12); sevenlumbar vertebrae(humans have five); threesacral vertebrae(as do most mammals, but humans have five); and a variable number ofcaudal vertebraein the tail (humans have only three to five vestigial caudal vertebrae, fused into an internalcoccyx).[62]: 11 The extra lumbar and thoracic vertebrae account for the cat's spinal mobility and flexibility. Attached to the spine are 13 ribs, the shoulder, and thepelvis.[62]: 16 Unlike human arms, cat forelimbs are attached to the shoulder by free-floatingclaviclebones which allow them to pass their body through any space into which they can fit their head.[63] Skull  Cat skull  A cat with its mouth open exposing its teeth The cat skull is unusual among mammals in having very largeeye socketsand a powerful specialized jaw.[64]: 35 Within the jaw, cats have teeth adapted for killing prey and tearing meat. When it overpowers its prey, a cat delivers a lethal neck bite with its two longcanine teeth, inserting them between two of the prey'svertebraeand severing itsspinal cord, causing irreversibleparalysisand death.[65]Compared to other felines, domestic cats have narrowly spaced canine teeth relative to the size of their jaw, which is an adaptation to their preferred prey of small rodents, which have small vertebrae.[65]Thepremolarand firstmolartogether compose thecarnassialpair on each side of the mouth, which efficiently shears meat into small pieces, like a pair of scissors. These are vital in feeding, since cats' smallmolarscannot chew food effectively, and cats are largely incapable of mastication.[64]: 37 Although cats tend to have better teeth than most humans, with decay generally less likely because of a thicker protective layer of enamel, a less damaging saliva, less retention of food particles between teeth, and a diet mostly devoid of sugar, they are nonetheless subject to occasional tooth loss and infection.[66] Claws  Shed claw sheaths Cats have protractible and retractable claws.[67]In their normal, relaxed position, the claws are sheathed with the skin and fur around the paw's toe pads. This keeps the claws sharp by preventing wear from contact with the ground and allows for the silent stalking of prey. The claws on the forefeet are typically sharper than those on the hindfeet.[68]Cats can voluntarily extend their claws on one or more paws. They may extend their claws in hunting or self-defense, climbing,kneading, or for extra traction on soft surfaces. Cats shed the outside layer of their claw sheaths when scratching rough surfaces.[69] Most cats have five claws on their front paws and four on their rear paws. Thedewclawisproximalto the other claws. More proximally is a protrusion which appears to be a sixth "finger". This special feature of the front paws on the inside of the wrists has no function in normal walking but is thought to be an antiskidding device used while jumping. Some cat breeds are prone to having extra digits ("polydactyly").[70]Polydactylous cats occur along North America's northeast coast and in Great Britain.[71] Ambulation The cat isdigitigrade. It walks on the toes, with the bones of the feet making up the lower part of the visible leg.[72]Unlike most mammals, it uses a "pacing"gaitand moves both legs on one side of the body before the legs on the other side. It registers directly by placing each hind paw close to the track of the corresponding fore paw, minimizing noise and visible tracks. This also provides sure footing for hind paws when navigating rough terrain. As it speeds up from walking to trotting, its gait changes to a "diagonal" gait: The diagonally opposite hind and fore legs move simultaneously.[73] Balance 13:37 Comparison of cat righting reflexes ingravityand zero gravity Most breeds of cat are noted fond of sitting in high places, orperching. A higher place may serve as a concealed site from which to hunt; domestic cats strike prey by pouncing from a perch such as a tree branch. Another possible explanation is that height gives the cat a better observation point, allowing it to survey its territory. A cat falling from heights of up to 3 meters (9.8ft) can right itself and land on its paws.[74] During a fall from a high place, a cat reflexively twists its body and rights itself to land on its feet using its acute sense of balance and flexibility. This reflex is known as thecat righting reflex.[75]A cat always rights itself in the same way during a fall, if it has enough time to do so, which is the case in falls of 90cm (2ft 11in) or more.[76]How cats are able to right themselves when falling has been investigated as the "falling cat problem". Senses Main article:Cat senses Vision  Reflection of camera flash from thetapetum lucidum Cats have excellentnight visionand can see at only one-sixth the light level required for human vision.[64]: 43 This is partly the result of cat eyes having atapetum lucidum, which reflects any light that passes through theretinaback into the eye, thereby increasing the eye's sensitivity to dim light.[77]Large pupils are an adaptation to dim light. The domestic cat hasslit pupils, which allow it to focus bright light withoutchromatic aberration.[78]At low light, a cat's pupils expand to cover most of the exposed surface of its eyes.[79]The domestic cat has rather poorcolor visionand only two types ofcone cells, optimized for sensitivity to blue and yellowish green; its ability to distinguish between red and green is limited.[80]A response to middle wavelengths from a system other than therod cellsmight be due to a third type of cone. This appears to be an adaptation to low light levels rather than representing truetrichromaticvision.[81] Hearing The domestic cat's hearing is most acute in the range of 500Hz to 32kHz.[82]It can detect an extremely broad range of frequencies ranging from 55Hz to 79,000Hz. It can hear a range of 10.5octaves, while humans and dogs can hear ranges of about 9 octaves.[83][84]Its hearing sensitivity is enhanced by its large movable outer ears, thepinnae, which amplify sounds and help detect the location of a noise. It can detectultrasound, which enables it to detect ultrasonic calls made byrodentprey.[85][86]Recent research has shown that cats have socio-spatial cognitive abilities to create mental maps of owners' locations based on hearing owners' voices.[87] Smell Cats have an acute sense of smell, due in part to their well-developedolfactory bulband a large surface ofolfactory mucosa, about5.8 square centimetres (29⁄32square inch) in area, which is about twice that of humans.[88]Cats and many other animals have aJacobson's organin their mouths that is used in the behavioral process offlehmening. It allows them to sense certain aromas in a way that humans cannot. Cats are sensitive topheromonessuch as3-mercapto-3-methylbutan-1-ol,[89]which they use to communicate throughurine sprayingand marking withscent glands.[90]Many cats also respond strongly to plants that containnepetalactone, especiallycatnip, as they can detect that substance at less than one part per billion.[91]About 70–80% of cats are affected by nepetalactone.[92]This response is also produced by other plants, such as silver vine (Actinidia polygama) and the herbvalerian; it may be caused by the smell of these plants mimicking a pheromone and stimulating cats' social or sexual behaviors.[93] Taste Cats have relatively fewtaste budscompared to humans (470 or so versus more than 9,000 on the human tongue).[94]Domestic and wild cats share ataste receptor gene mutationthat keeps their sweet taste buds from binding to sugary molecules, leaving them with no ability to tastesweetness.[95]Their taste buds instead respond toacids,amino acidslike protein, and bitter tastes.[96]Cats also have a distinct temperature preference for their food, preferring food with a temperature around 38°C (100°F) which is similar to that of a fresh kill and routinely rejecting food presented cold or refrigerated (which would signal to the cat that the "prey" item is long dead and therefore possibly toxic or decomposing).[94] Whiskers  The whiskers of a cat are highly sensitive to touch To aid with navigation and sensation, cats have dozens of movablewhiskers (vibrissae)over their body, especially their faces. These provide information on the width of gaps and on the location of objects in the dark, both by touching objects directly and by sensing air currents; they also trigger protectiveblink reflexesto protect the eyes from damage.[64]: 47  Behavior See also:Cat behavior  Cat lying onrice straw Outdoor cats are active both day and night, although they tend to be slightly more active at night.[97]Domestic cats spend the majority of their time in the vicinity of their homes but can range many hundreds of meters from this central point. They establishterritoriesthat vary considerably in size, in one study ranging from 7to 28 hectares (17–69 acres).[98]The timing of cats' activity is quite flexible and varied, which means house cats may be moreactive in the morning and evening, as a response to greater human activity at these times.[99] Cats conserve energy by sleeping more than most animals, especially as they grow older. The daily duration of sleep varies, usually between 12 and 16 hours, with 13 and 14 being the average. Some cats can sleep as much as 20 hours. The term "cat nap" for a short rest refers to the cat's tendency to fall asleep (lightly) for a brief period. While asleep, cats experience short periods ofrapid eye movement sleepoften accompanied by muscle twitches, which suggests they are dreaming.[100] Sociability The social behavior of the domestic cat ranges from widely dispersed individuals toferal cat coloniesthat gather around a food source, based on groups of co-operating females.[101][102]Within such groups, one cat is usually dominant over the others.[103]Each cat in a colony holds a distinct territory, with sexually active males having the largest territories, which are about 10 times larger than those of female cats and may overlap with several females' territories. These territories are marked byurine spraying, by rubbing objects at head height with secretions from facial glands, and bydefecation.[90]Between these territories are neutral areas where cats watch and greet one another without territorial conflicts. Outside these neutral areas, territory holders usually chase away stranger cats, at first by staring, hissing, andgrowlingand, if that does not work, by short but noisy and violent attacks. Despite this colonial organization, cats do not have a social survival strategy or apack mentality, and always hunt alone.[104] Life in proximity to humans and other domestic animals has led to a symbiotic social adaptation in cats, and cats may express great affection toward humans or other animals.Ethologically, a cat's human keeper functions as if a mother surrogate.[105]Adult cats live their lives in a kind of extended kittenhood, a form of behavioralneoteny. Their high-pitched sounds may mimic the cries of a hungry human infant, making them particularly difficult for humans to ignore.[106]Some pet cats are poorly socialized. In particular, older cats show aggressiveness toward newly arrived kittens, which include biting and scratching; this type of behavior is known as feline asocial aggression.[107] Redirected aggressionis a common form of aggression which can occur in multiple cat households. In redirected aggression there is usually something that agitates the cat: this could be a sight, sound, or another source of stimuli which causes a heightened level of anxiety or arousal. If the cat cannot attack the stimuli, it may direct anger elsewhere by attacking or directing aggression to the nearest cat, dog, human or other being.[108][109] Domestic cats'scent rubbingbehavior toward humans or other cats is thought to be a feline means for social bonding.[110] Communication Main article:Cat communication  Vocalizing domestic cat Domestic cats use manyvocalizationsfor communication, includingpurring,trilling, hissing, growling/snarling, grunting, and several different forms of meowing.[7]Theirbody language, including position of ears and tail, relaxation of the whole body, and kneading of the paws, are all indicators of mood. The tail and ears are particularly important social signal mechanisms in cats. A raised tail indicates a friendly greeting, and flattened ears indicates hostility. Tail-raising also indicates the cat's position in the group'ssocial hierarchy, with dominant individuals raising their tails less often than subordinate ones.[111]Feral cats are generally silent.[112]: 208 Nose-to-nose touching is also a common greeting and may be followed bysocial grooming, which is solicited by one of the cats raising and tilting its head.[102] Purringmay have developed as an evolutionary advantage as a signaling mechanism of reassurance between mother cats andnursingkittens, who are thought to use it as a care-soliciting signal.[113]Post-nursing cats also often purr as a sign of contentment: when being petted, becoming relaxed,[114][115]or eating. Even though purring as popularly interpreted as indicative of pleasure, it has been recorded in a wide variety of circumstances, most of which involve physical contact between the cat and another, presumably trusted individual.[113]Some cats have been observed to purr continuously when chronically ill or in apparent pain.[116] The exact mechanism by which cats purr has long been elusive, but it has been proposed that purring is generated via a series of sudden build-ups and releases of pressure as theglottisis opened and closed, which causes thevocal foldsto separate forcefully. The laryngeal muscles in control of the glottis are thought to be driven by aneural oscillatorwhich generates a cycle of contraction and release every 30-40 milliseconds (giving a frequency of 33 to 25 Hz).[113][117][118] Grooming  The hookedpapillaeon a cat's tongue act like ahairbrushto help clean and detangle fur Cats are known for spending considerable amounts of time licking their coats to keep them clean.[119]The cat's tongue has backward-facing spines about 500μmlong, which are calledpapillae. These containkeratinwhich makes them rigid[120]so the papillae act like a hairbrush. Some cats, particularly longhaired cats, occasionally regurgitatehairballsof fur that have collected in their stomachs from grooming. These clumps of fur are usually sausage-shaped and about2–3cm (3⁄4–1+1⁄4in) long. Hairballs can be prevented with remedies that ease elimination of the hair through thegut, as well as regular grooming of the coat with a comb or stiff brush.[119] Fighting  A domestic cat's arched back, raised fur and an open-mouthed hiss are signs of aggression Among domestic cats, males are more likely to fight than females.[121]Among feral cats, the most common reason forcat fightingis competition between two males to mate with a female. In such cases, most fights are won by the heavier male.[122]Another common reason for fighting in domestic cats is the difficulty of establishing territories within a small home.[121]Female cats also fight over territory or to defend their kittens. Neutering will decrease or eliminate this behavior in many cases, suggesting that the behavior is linked tosex hormones.[123] When cats become aggressive, they try to make themselves appear larger and more threatening by raising their fur, arching their backs, turning sideways and hissing or spitting.[124]Often, the ears are pointed down and back to avoid damage to the inner ear and potentially listen for any changes behind them while focused forward. They may also vocalize loudly and bare their teeth in an effort to further intimidate their opponent. Fights usually consist of grappling and delivering powerful slaps to the face and body with the forepaws as well as bites. Cats also throw themselves to the ground in a defensive posture to rake their opponent's belly with their powerful hind legs.[125] Serious damage is rare, as the fights are usually short in duration, with the loser running away with little more than a few scratches to the face and ears. Fights for mating rights are typically more severe and injuries may include deep puncture wounds and lacerations. Normally, serious injuries from fighting are limited to infections of scratches and bites, though these can occasionally kill cats if untreated. In addition, bites are probably the main route of transmission offeline immunodeficiency virus.[126]Sexually active males are usually involved in many fights during their lives, and often have decidedly battered faces with obvious scars and cuts to their ears and nose.[127] Hunting and feeding See also:Cat nutrition  A domestic cat with its prey, adeermouse Cat "playing" with a mouse is interrupted by dog in Estonia, Kõrvemaa (July 2022) The shape and structure of cats' cheeks is insufficient to allow them to take in liquids using suction. Therefore, when drinking they lap with the tongue to draw liquid upward into their mouths. Lapping at a rate of four times a second, the cat touches the smooth tip of its tongue to the surface of the water, and quickly retracts it like a corkscrew, drawing water upward.[128][129] Feral cats and free-fed house cats consume several small meals in a day. The frequency and size of meals varies between individuals. They select food based on its temperature, smell and texture; they dislike chilled foods and respond most strongly to moist foods rich in amino acids, which are similar to meat. Cats reject novel flavors (a response termedneophobia) and learn quickly toavoid foods that have tasted unpleasantin the past.[104][130]It is also a common misconception that cats like milk/cream, as they tend to avoid sweet food and milk. Most adult cats arelactose intolerant; the sugar in milk is not easily digested and may cause soft stools ordiarrhea.[131]Some also develop odd eating habits and like to eat or chew on things like wool, plastic, cables, paper, string, aluminum foil, or even coal. This condition,pica, can threaten their health, depending on the amount and toxicity of the items eaten.[132] Cats hunt small prey, primarily birds and rodents,[133]and are often used as a form of pest control.[134][135]Cats use two hunting strategies, either stalking prey actively, orwaiting in ambushuntil an animal comes close enough to be captured.[136]The strategy used depends on the prey species in the area, with cats waiting in ambush outside burrows, but tending to actively stalk birds.[137]: 153 Domestic cats are a majorpredator of wildlifein the United States, killing an estimated 1.3 to 4.0 billion birds and 6.3 to 22.3 billion mammals annually.[138] Certain species appear more susceptible than others; in one English village, for example, 30% of house sparrow mortality was linked to the domestic cat.[139]In the recovery of ringed robins (Erithacus rubecula) and dunnocks (Prunella modularis) in Britain, 31% of deaths were a result of cat predation.[140]In parts of North America, the presence of larger carnivores such ascoyoteswhich prey on cats and other small predators reduces the effect of predation by cats and other small predators such asopossumsandraccoonson bird numbers and variety.[141] Perhaps the best-known element of cats' hunting behavior, which is commonly misunderstood and often appalls cat owners because it looks like torture, is that cats often appear to "play" with prey by releasing it after capture. Thiscat and mousebehavior is due to an instinctive imperative to ensure that the prey is weak enough to be killed without endangering the cat.[142] Another poorly understood element of cat hunting behavior is the presentation of prey to human guardians. One explanation is that cats adopt humans into their social group and share excess kill with others in the group according to thedominance hierarchy, in which humans are reacted to as if they are at, or near, the top.[143]Another explanation is that they attempt to teach their guardians to hunt or to help their human as if feeding "an elderly cat, or an inept kitten".[144]This hypothesis is inconsistent with the fact that male cats also bring home prey, despite males having negligible involvement in raising kittens.[137]: 153  Play Main article:Cat play and toys Play fight between kittens aged 14 weeks Domestic cats, especially young kittens, are known for their love of play. This behavior mimics hunting and is important in helping kittens learn to stalk, capture, and kill prey.[145]Cats also engage in play fighting, with each other and with humans. This behavior may be a way for cats to practice the skills needed for real combat, and might also reduce any fear they associate with launching attacks on other animals.[146] Cats also tend to play with toys more when they are hungry.[147]Owing to the close similarity between play and hunting, cats prefer to play with objects that resemble prey, such as small furry toys that move rapidly, but rapidly lose interest. They becomehabituatedto a toy they have played with before.[148]String is often used as a toy, but if it is eaten, it can become caught at the base of the cat's tongue and then move into theintestines, a medical emergency which can cause serious illness, even death.[149]Owing to the risks posed by cats eating string, it is sometimes replaced with alaser pointer's dot, which cats may chase.[150] Reproduction  When cats mate, the tomcat (male) bites the scruff of the female's neck as she assumes a position conducive tomatingknown aslordosis behavior. See also:Kitten Female cats, called queens, arepolyestrouswith severalestruscycles during a year, lasting usually 21 days. They are usually ready to mate between early February and August.[151] Several males, called tomcats, are attracted to a female in heat. They fight over her, and the victor wins the right to mate. At first, the female rejects the male, but eventually, the female allows the male to mate. The female utters a loud yowl as the male pulls out of her because a male cat'spenishas a band of about 120–150 backward-pointingpenile spines, which are about1mm (1⁄32in) long; upon withdrawal of the penis, the spines may provide the female with increased sexual stimulation, which acts toinduce ovulation.[152] After mating, the female cleans hervulvathoroughly. If a male attempts to mate with her at this point, the female attacks him. After about 20 to 30 minutes, once the female is finished grooming, the cycle will repeat.[153]Because ovulation is not always triggered by a single mating, females may not be impregnated by the first male with which they mate.[154]Furthermore, cats aresuperfecund; that is, a female may mate with more than one male when she is in heat, with the result that different kittens in a litter may have different fathers.[153] Themorulaforms 124 hours after conception. At 148 hours, earlyblastocystsform. At 10–12 days, implantation occurs.[155]Thegestationof queens lasts between 64 and 67 days, with an average of 65 days.[151][156]  Radiography of a pregnant cat. The skeletons of two fetuses are visible on the left and right of the uterus.  A newborn kitten Data on the reproductive capacity of more than 2,300 free-ranging queens were collected during a study between May 1998 and October 2000. They had one to six kittens perlitter, with an average of three kittens. They produced a mean of 1.4 litters per year, but a maximum of three litters in a year. Of 169 kittens, 127 died before they were six months old due to a trauma caused in most cases by dog attacks and road accidents.[9]The first litter is usually smaller than subsequent litters. Kittens are weaned between six and seven weeks of age. Queens normally reach sexual maturity at 5–10 months, and males at 5–7 months. This varies depending on breed.[153]Kittens reachpubertyat the age of 9–10 months.[151] Cats are ready to go to new homes at about 12 weeks of age, when they are ready to leave their mother.[157]They can be surgicallysterilized(spayed orcastrated) as early as seven weeks to limit unwanted reproduction.[158]This surgery also prevents undesirable sex-related behavior, such as aggression,territory marking(spraying urine) in males and yowling (calling) in females. Traditionally, this surgery was performed at around six to nine months of age, but it is increasingly being performed beforepuberty, at about three to six months.[159]In the United States, about 80% of household cats are neutered.[160] Lifespan and health Main articles:Cat healthandAging in cats The average lifespan of pet cats has risen in recent decades. In the early 1980s, it was about seven years,[161]: 33 [162]rising to 9.4 years in 1995[161]: 33 and about 15 years in 2021. Some cats have been reported as surviving into their 30s,[163]with the oldest known cat,Creme Puff, dying at a verified age of 38.[164] Neutering increases life expectancy: one study found castrated male cats live twice as long as intact males, while spayed female cats live 62% longer than intact females.[161]: 35 Having a catneuteredconfers health benefits, because castrated males cannot developtesticular cancer, spayed females cannot developuterineorovarian cancer, and both have a reduced risk ofmammary cancer.[165] Disease Main article:Feline diseases About 250 heritablegenetic disordershave been identified in cats, many similar to humaninborn errors of metabolism.[166]The high level of similarity among themetabolismof mammals allows many of these feline diseases to be diagnosed usinggenetic teststhat were originally developed for use in humans, as well as the use of cats asanimal modelsin the study of the human diseases.[167][168]Diseases affecting domestic cats include acute infections,parasitic infestations, injuries, and chronic diseases such askidney disease,thyroid disease, andarthritis.Vaccinationsare available for many infectious diseases, as are treatments to eliminate parasites such as worms, ticks, and fleas.[169] Ecology Habitats  Atabby catin snowy weather The domestic cat is acosmopolitan speciesand occurs across much of the world.[59]It is adaptable and now present on all continents exceptAntarctica, and on 118 of the 131 main groups of islands, even on the isolatedKerguelen Islands.[170][171]Due to its ability to thrive in almost any terrestrial habitat, it is among the world's mostinvasive species.[172]It lives on small islands with no human inhabitants.[173]Feral cats can live in forests, grasslands, tundra, coastal areas, agricultural land, scrublands, urban areas, and wetlands.[174] The unwantedness that leads to the domestic cat being treated as an invasive species is twofold. On one hand, as it is little altered from the wildcat, it can readily interbreed with the wildcat. Thishybridizationposes a danger to the genetic distinctiveness of some wildcat populations, particularly inScotlandandHungary, possibly also theIberian Peninsula, and where protected natural areas are in close proximity to human-dominated landscapes, such asKruger National ParkinSouth Africa.[175][56]On the other hand, and perhaps more obviously, its introduction to places where no native felines are present contributes to the decline of native species.[176] Ferality Main article:Feral cat  Feralfarm cat Feral cats are domestic cats that were born in or have reverted to a wild state. They are unfamiliar with and wary of humans and roam freely in urban and rural areas.[10]The numbers of feral cats is not known, but estimates of the United States feral population range from 25 to 60 million.[10]Feral cats may live alone, but most are found in largecolonies, which occupy a specific territory and are usually associated with a source of food.[177]Famous feral cat colonies are found in Rome around theColosseumandForum Romanum, with cats at some of these sites being fed and given medical attention by volunteers.[178] Public attitudes toward feral cats vary widely, from seeing them as free-ranging pets to regarding them as vermin.[179] Some feral cats can be successfully socialized and 're-tamed' for adoption; young cats, especially kittens[180]and cats that have had prior experience and contact with humans are the most receptive to these efforts. Impact on wildlife Main article:Cat predation on wildlife On islands, birds can contribute as much as 60% of a cat's diet.[181]In nearly all cases, the cat cannot be identified as the sole cause for reducing the numbers of island birds, and in some instances, eradication of cats has caused a "mesopredator release" effect;[182]where the suppression of top carnivores creates an abundance of smaller predators that cause a severe decline in their shared prey. Domestic cats are a contributing factor to the decline of many species, a factor that has ultimately led, in some cases, to extinction.The South Island piopio,Chatham rail,[140]and theNew Zealand merganser[183]are a few from a long list, with the most extreme case being the flightlessLyall's wren, which was driven to extinction only a few years after its discovery.[184][185]One feral cat in New Zealand killed 102New Zealand lesser short-tailed batsin seven days.[186]In the US, feral and free-ranging domestic cats kill an estimated 6.3 – 22.3 billion mammals annually.[138] In Australia, the impact of cats on mammal populations is even greater than the impact of habitat loss.[187]More than one million reptiles are killed by feral cats each day, representing 258 species.[188]Cats have contributed to the extinction of theNavassa curly-tailed lizardandChioninia coctei.[176] Interaction with humans Main article:Human interaction with cats  A cat sleeping on a man's lap Cats are commonpetsthroughout the world, and their worldwide population as of 2007 exceeded 500million.[189]Cats have been used for millennia to control rodents, notablyaround grain storesandaboard ships, and both uses extend to the present day.[190][191] As well as being kept as pets, cats are also used in the internationalfur trade[192]and leather industries for making coats, hats, blankets, and stuffed toys;[193]and shoes, gloves, and musical instruments respectively[194](about 24 cats are needed to make a cat-fur coat).[195]This use has been outlawed in the United States since 2000 and in the European Union (as well as the United Kingdom) since 2007.[196] Cat pelts have been used for superstitious purposes as part of the practice ofwitchcraft,[197]and are still made into blankets inSwitzerlandastraditional medicinethought to curerheumatism.[198] A few attempts to build a cat census have been made over the years, both through associations or national and international organizations (such as that of theCanadian Federation of Humane Societies[199]) and over the Internet,[200][201]but such a task does not seem simple to achieve. General estimates for the global population of domestic cats range widely from anywhere between 200 million to 600 million.[202][203][204][205][206]Walter Chandohamade his career photographing cats after his 1949 images ofLoco, an especially charming stray taken in, were published around the world. He is reported to have photographed 90,000 cats during his career and maintained an archive of 225,000 images that he drew from for publications during his lifetime.[207] Shows Main article:Cat show Acat showis a judged event in which the owners of cats compete to win titles in various cat-registering organizations by entering their cats to be judged after a breed standard.[208]It is often required that a cat must be healthy and vaccinated in order to participate in a cat show.[208]Bothpedigreedand non-purebredcompanion ("moggy") cats are admissible, although the rules differ depending on the organization. Competing cats are compared to the applicable breed standard, and assessed for temperament.[208] Infection Main article:Feline zoonosis Cats can be infected or infested withviruses,bacteria,fungus,protozoans,arthropodsor worms that can transmit diseases to humans.[209]In some cases, the cat exhibits nosymptomsof the disease.[210]The same disease can then become evident in a human. The likelihood that a person will become diseased depends on the age andimmunestatus of the person. Humans who have cats living in their home or in close association are more likely to become infected. Others might also acquire infections from catfecesandparasitesexiting the cat's body.[209][211]Some of the infections of most concern includesalmonella,cat-scratch diseaseandtoxoplasmosis.[210] History and mythology Main articles:Cultural depictions of catsandCats in ancient Egypt Inancient Egypt, cats wereworshipped, and the goddessBastetoften depicted in cat form, sometimes taking on the war-like aspect of a lioness. The Greek historianHerodotusreported that killing a cat was forbidden, and when a household cat died, the entire family mourned and shaved their eyebrows. Families took their dead cats to the sacred city ofBubastis, where they were embalmed and buried in sacred repositories. Herodotus expressed astonishment at the domestic cats in Egypt, because he had only ever seen wildcats.[212] Ancient Greeks and Romans keptweaselsas pets, which were seen as the ideal rodent-killers. The earliest unmistakable evidence of the Greeks having domestic cats comes from two coins fromMagna Graeciadating to the mid-fifth century BC showing Iokastos and Phalanthos, the legendary founders ofRhegionandTarasrespectively, playing with their pet cats. The usual ancient Greek word for 'cat' wasailouros, meaning 'thing with the waving tail'. Cats are rarely mentioned inancient Greek literature.Aristotleremarked in hisHistory of Animalsthat "female cats are naturallylecherous." The Greeks latersyncretizedtheir own goddessArtemiswith the Egyptian goddess Bastet, adopting Bastet's associations with cats and ascribing them to Artemis. InOvid'sMetamorphoses, when the deities flee to Egypt and take animal forms, the goddessDianaturns into a cat.[213][214] Cats eventually displacedweaselsas the pest control of choice because they were more pleasant to have around the house and were more enthusiastic hunters of mice. During theMiddle Ages, many of Artemis's associations with cats were grafted onto theVirgin Mary. Cats are often shown in icons ofAnnunciationand of theHoly Familyand, according toItalian folklore, on the same night that Mary gave birth toJesus, a cat inBethlehemgave birth to a kitten.[215]Domestic cats were spread throughout much of the rest of the world during theAge of Discovery, asships' catswere carried onsailing shipsto control shipboard rodents and as good-luck charms.[50] Several ancient religions believed cats are exalted souls, companions or guides for humans, that are all-knowing but mute so they cannot influence decisions made by humans. In Japan, themaneki nekocat is a symbol of good fortune.[216]InNorse mythology,Freyja, the goddess of love, beauty, and fertility, is depicted as riding a chariot drawn by cats.[217]InJewish legend, the first cat was living in the house of the first manAdamas a pet that got rid ofmice. The cat was once partnering with the first dog before the latter broke an oath they had made which resulted in enmity between the descendants of these two animals. It is also written that neither cats norfoxesare represented in the water, while every other animal has an incarnation species in the water.[218]Although no species are sacred in Islam,cats are revered by Muslims. Some Western writers have statedMuhammadhad a favorite cat,Muezza.[219]He is reported to have loved cats so much, "he would do without his cloak rather than disturb one that was sleeping on it".[220]The story has no origin in early Muslim writers, and seems to confuse a story of a laterSufisaint,Ahmed ar-Rifa'i, centuries after Muhammad.[221]One of the companions of Muhammad was known asAbu Hurayrah("father of the kitten"), in reference to his documented affection to cats.[222]  The ancient Egyptiansmummifieddead cats out of respect in the same way that they mummified people[4]  AncientRoman mosaicof a cat killing apartridgefrom theHouse of the FauninPompeii  A 19th-century drawing of a tabby cat Superstitions and rituals  Some cultures are superstitious about black cats, ascribing either good or bad luck to them Many cultures have negativesuperstitionsabout cats. An example would be the belief that encountering ablack cat("crossing one's path") leads to bad luck, or that cats are witches'familiarsused to augment a witch's powers and skills. The killing of cats in MedievalYpres,Belgium, is commemorated in the innocuous present-dayKattenstoet(cat parade).[223]In mid-16th century France,cats would be burnt aliveas a form of entertainment. According toNorman Davies, the assembled people "shrieked with laughter as the animals, howling with pain, were singed, roasted, and finallycarbonized".[224] James Frazerwrote that "It was the custom to burn a basket, barrel, or sack full of live cats, which was hung from a tall mast in the midst of the bonfire; sometimes afoxwas burned. The people collected the embers and ashes of the fire and took them home, believing that they brought good luck. The French kings often witnessed these spectacles and even lit the bonfire with their own hands. In 1648Louis XIV, crowned with a wreath of roses and carrying a bunch of roses in his hand, kindled the fire, danced at it and partook of the banquet afterwards in the town hall. But this was the last occasion when a monarch presided at the midsummer bonfire in Paris. AtMetzmidsummer fires were lighted with great pomp on the esplanade, and a dozen cats, enclosed inwickercages, were burned alive in them, to the amusement of the people. Similarly, atGap, in thedepartmentof theHautes-Alpes, cats used to be roasted over the midsummer bonfire."[225] According to a myth in many cultures, cats have multiple lives. In many countries, they are believed to have nine lives, but in Italy, Germany, Greece, Brazil and some Spanish-speaking regions, they are said to have seven lives,[226][227]while in Arabic traditions, the number of lives is six.[228]The myth is attributed to the natural suppleness and swiftness cats exhibit to escape life-threatening situations.[citation needed]Also lending credence to this myth is the fact that falling cats often land on their feet, using an instinctiverighting reflexto twist their bodies around. Nonetheless, cats can still be injured or killed by a high fall.[229]

Lamb,hogget, andmutton, genericallysheep meat,are the meat of domesticsheep,Ovis aries. A sheep in its first year is a lamb and its meat is also lamb. The meat from sheep in their second year is hogget. Older sheep meat is mutton. Generally, "hogget" and "sheep meat" are not used by consumers outside Norway, New Zealand, South Africa, Scotland and Australia. Hogget has become more common in England, particularly in the North (Lancashire and Yorkshire) often in association with rare breed and organic farming. InSouth AsianandCaribbeancuisine, "mutton" often meansgoat meat.At various times and places, "mutton" or "goat mutton" has occasionally been used to mean goat meat. Lamb is the most expensive of the three types and in recent decades sheep meat is increasingly only retailed as "lamb", sometimes stretching the accepted distinctions given above. The stronger-tasting mutton is now hard to find in many areas, despite the efforts of theMutton Renaissance Campaignin the UK. In Australia, the termprime lambis often used to refer to lambs raised for meat.Other languages, such asFrench,Spanish,ItalianandArabic, make similar or even more detailed distinctions among sheep meats by age and sometimes by sex and diet—for example,lechazoin Spanish refers to meat from milk-fed (unweaned) lambs.

All Muscovy ducks have longclawson their feet and a wide, flat tail. In the domestic drake (male), length is about 86cm (34in) and weight is 4.6–6.8kg (10–15lb), while the domestic hen (female) is much smaller, at 64cm (25in) in length and 2.7–3.6kg (6.0–7.9lb) in weight. Large domesticated males often weigh up to 8kg (18lb), and large domesticated females up to 5kg (11lb). The true wild Muscovy duck, from which all domestic Muscovies originated, is blackish, with large white wing patches. Length can range from 66 to 84cm (26 to 33in), wingspan from 137 to 152cm (54 to 60in) and weight from 1.1 to 4.1kg (2.4 to 9.0lb). On the head, the wild male has a short crest on the nape. The bill is black with a speckling of pale pink. A blackish or dark red knob can be seen at the bill base, which is similar in colour to the bare skin of the face. The eyes are yellowish-brown. The legs and webbed feet are blackish. The wild female is similar in plumage, but much smaller, with a feathered face and lacking the prominent knob. The juvenile is duller overall, with little or no white on the upperwing. Domesticated birds may look similar; most are dark brown or black mixed with white, particularly on the head.Other colors, such as lavender or all-white, are also seen. Both sexes have a nude black-and-red or all-red face; the drake also has pronouncedcarunclesat the base of the bill and a low erectilecrestof feathers.[8]C. moschataducklings are mostly yellow with buff-brown markings on the tail and wings. For a while after hatching, juveniles lack the distinctive wattles associated with adult individuals, and resemble the offspring of various other ducks, such asmallards. Some domesticated ducklings have a dark head and blue eyes, others a light brown crown and dark markings on their nape. They are agile and speedyprecocialbirds. The drake has a low breathy call, and the hen a quiet trilling coo. Thekaryotypeof the Muscovy duck is 2n=80, consisting of three pairs ofmacrochromosomes, 36 pairs ofmicrochromosomes, and a pair ofsex chromosomes. The two largest macrochromosome pairs aresubmetacentric, while all otherchromosomesareacrocentricor probablytelocentricfor the smallest microchromosomes. The submetacentric chromosomes and theZ (female) chromosomeshow rather littleconstitutive heterochromatin(C bands), while theW chromosomesare at least two-thirds heterochromatin. Male Muscovy ducks havehelicalpenises that become erect to 19cm (7in) in 0.3s. Females have vaginas that coil in the opposite direction that appear to have evolved to limitforced copulationby males.

Her mom protect your child.

Fishareaquatic,craniate,gill-bearing animals that lacklimbswithdigits. Included in this definition are the livinghagfish,lampreys, andcartilaginousandbony fishas well as various extinct related groups. Approximately 95% of living fish species are ray-finned fish, belonging to the classActinopterygii, with around 99% of those beingteleosts. Fish Temporal range:535–0Ma PreꞒ Ꞓ O S D C P T J K Pg N Middle Cambrian-Recent Giant grouperswimming amongschoolsof other fishHead-on view of ared lionfishScientific classificationKingdom:AnimaliaPhylum:ChordataClade:OlfactoresSubphylum:VertebrataGroups includedJawless fish†Armoured fish†Spiny sharksCartilaginous fishBony fishRay-finned fishLobe-finned fishCladisticallyincluded but traditionally excluded taxaTetrapods†Conodonts The earliest organisms that can be classified as fish were soft-bodiedchordatesthat first appeared during theCambrianperiod. Although they lacked atrue spine, they possessednotochordswhich allowed them to be more agile than their invertebrate counterparts. Fish would continue to evolve through thePaleozoicera, diversifying into a wide variety of forms. Many fish of the Paleozoic developedexternal armorthat protected them from predators. The first fish withjawsappeared in theSilurianperiod, after which many (such assharks) became formidable marine predators rather than just the prey ofarthropods. Most fish areectothermic("cold-blooded"), allowing their body temperatures to vary as ambient temperatures change, though some of the large active swimmers likewhite sharkandtunacan hold a highercore temperature.[1][2]Fish can acoustically communicate with each other, most often in the context of feeding, aggression or courtship.[3] Fish are abundant in most bodies of water. They can be found in nearly all aquatic environments, from high mountain streams (e.g.,charandgudgeon) to theabyssaland evenhadaldepths of the deepest oceans (e.g.,cusk-eelsandsnailfish), although no species has yet been documented in the deepest 25% of the ocean.[4]With 34,300 described species, fish exhibit greater species diversity than any other group of vertebrates.[5] Fish are an important resource for humans worldwide, especiallyas food. Commercial and subsistence fishers hunt fish inwild fisheriesorfarmthem in ponds or in cages in the ocean (inaquaculture). They are also caught byrecreational fishers, kept as pets, raised byfishkeepers, and exhibited in publicaquaria. Fish have had a role in culture through the ages, serving as deities, religious symbols, and as the subjects of art, books and movies. Tetrapods(amphibians,reptiles,birdsandmammals) emerged withinlobe-finned fishes, socladisticallythey are fish as well. However, traditionally fish (piscesorichthyes) are renderedparaphyleticby excluding the tetrapods, and are therefore not considered a formal taxonomic grouping insystematic biology, unless it is used in thecladisticsense, including tetrapods,[6][7]although usually "vertebrate" is preferred and used for this purpose (fish plus tetrapods) instead. Furthermore,cetaceans, although mammals, have often been considered fish by various cultures and timeperiods. Contents Etymology The word forfishin English and the otherGermanic languages(GermanFisch;Gothicfisks) is inherited fromProto-Germanic, and is related to theLatinpiscisandOld Irishīasc, though the exact root is unknown; some authorities reconstruct anProto-Indo-Europeanroot*peysk-, attested only inItalic,Celtic, andGermanic.[8][9][10][11] The English word once had a much broader usage than its current biological meaning. Names such asstarfish,jellyfish,shellfishandcuttlefishattest to almost any fully aquatic animal (including whales) once beingfish. "Correcting" such names (e.g. tosea star) is an attempt to retroactively apply the current meaning offishto words that were coined when it had a different meaning. Evolution Main article:Evolution of fish Fish, as vertebrata, developed as sister of the tunicata. As the tetrapods emerged deep within the fishes group, as sister of the lungfish, characteristics of fish are typically shared by tetrapods, including having vertebrae and a cranium.  Dunkleosteuswas a gigantic, 10-metre (33ft) longprehistoric fishof class Placodermi.  Lower jaw of the placodermEastmanosteuspustulosus, showing the shearing structures ("teeth") on its oral surface; from theDevonianofWisconsin Early fish from the fossil record are represented by a group of small, jawless, armored fish known asostracoderms. Jawless fish lineages are mostly extinct. An extant clade, thelampreysmay approximate ancient pre-jawed fish. The first jaws are found inPlacodermifossils. They lacked distinct teeth, having instead the oral surfaces of their jaw plates modified to serve the various purposes of teeth. The diversity of jawed vertebrates may indicate the evolutionary advantage of ajawed mouth. It is unclear if the advantage of a hinged jaw is greater biting force, improved respiration, or a combination of factors. Fish may have evolved from a creature similar to a coral-likesea squirt, whose larvae resemble primitive fish in important ways. The first ancestors of fish may havekept the larval form into adulthood(as some sea squirts do today). Phylogeny Fishes are aparaphyleticgroup: that is, anycladecontaining all fish also contains thetetrapods, which are not fish (though they include fish-shaped forms, such asWhales and Dolphinsor theextinctichthyosaurs, which acquired a fish-like body shape due tosecondary aquatic adaptation, seeevolution of cetaceans). The followingcladogramshowsclades- some with, some withoutextantrelatives - that are traditionally considered as "fishes" (cyanline) and the tetrapods (four-limbed vertebrates), which are mostly terrestrial.Extinctgroups are marked with adagger(†). Vertebrata/ Agnatha/  Hyperoartia(lampreys)    Myxini(hagfish)  Cyclostomes   †Euconodonta     †Pteraspidomorphi    †Thelodonti     †Anaspida     †Galeaspida     †Pituriaspida    †Osteostraci  Gnathostomata  "†Placodermi" (armoured fishes,paraphyletic)[13]     "†Acanthodii" ("spiny sharks",paraphyleticorpolyphyletic)[14]   Chondrichthyes  "†Acanthodii" ("spiny sharks",paraphyleticorpolyphyletic)     Holocephali(ratfish)    Euselachii(sharks,rays)   (cartilaginousfishes)Euteleostomi/  "†Acanthodii" ("spiny sharks",paraphyleticorpolyphyletic)    Actinopterygii  Cladistia(bichirs,reedfish)     Chondrostei(sturgeons,paddlefish)    Neopterygii(includesTeleostei, 96% of living fishspecies)   (ray‑finnedfishes)Sarcopterygii  †Onychodontiformes    Actinistia(coelacanths)  Rhipidistia   †Porolepiformes    Dipnoi(lungfishes)   Tetrapodomorpha/   †Rhizodontimorpha     †Tristichopteridae     †Tiktaalik  Tetrapoda  †Ichthyostega    crown-grouptetrapods  four‑limbedvertebrates   (Choanata) (lobe‑finnedfish)  Osteichthyes  (jawedvertebrates)     "Fishes" Craniata Taxonomy  Leedsichthys,of the subclass Actinopterygii, is the largest known fish, with estimates in 2005 putting its maximum size at 16 metres (52ft). Fishes are aparaphyleticgroup and for this reason, groups such as the classPiscesseen in older reference works are no longer used in formal classifications. Traditional classification divides fish into threeextantclasses, and with extinct forms sometimes classified within the tree, sometimes as their own classes:[15][16] ClassAgnatha(jawless fish) SubclassCyclostomata(hagfishandlampreys) SubclassOstracodermi(armoured jawless fish) † ClassChondrichthyes(cartilaginous fish) SubclassElasmobranchii(sharksandrays) SubclassHolocephali(chimaerasand extinct relatives) ClassPlacodermi(armoured fish) † ClassAcanthodii("spiny sharks", sometimes classified under bony fishes)† ClassOsteichthyes(bony fish) SubclassActinopterygii(ray finned fishes) SubclassSarcopterygii(fleshy finned fishes, ancestors of tetrapods) The above scheme is the one most commonly encountered in non-specialist and general works. Many of the above groups are paraphyletic, in that they have given rise to successive groups: Agnathans are ancestral to Chondrichthyes, who again have given rise to Acanthodiians, the ancestors of Osteichthyes. With the arrival ofphylogenetic nomenclature, the fishes has been split up into a more detailed scheme, with the following major groups: Class Myxini (hagfish) ClassPteraspidomorphi† (early jawless fish) ClassThelodonti† ClassAnaspida† ClassPetromyzontida or Hyperoartia Petromyzontidae (lampreys) ClassConodonta(conodonts) † ClassCephalaspidomorphi† (early jawless fish) (unranked)Galeaspida† (unranked)Pituriaspida† (unranked)Osteostraci† InfraphylumGnathostomata(jawed vertebrates) ClassPlacodermi† (armoured fish) ClassChondrichthyes(cartilaginous fish) ClassAcanthodii† (spiny sharks) SuperclassOsteichthyes(bony fish) ClassActinopterygii(ray-finned fish) SubclassChondrostei OrderAcipenseriformes(sturgeonsandpaddlefishes) OrderPolypteriformes(reedfishesandbichirs). SubclassNeopterygii InfraclassHolostei(garsandbowfins) InfraclassTeleostei(many orders of common fish) ClassSarcopterygii(lobe-finned fish) SubclassActinistia(coelacanths) Subclass Dipnoi (lungfish, sister group to thetetrapods) † – indicates extinct taxon Some palaeontologists contend that becauseConodontaarechordates, they are primitive fish. For a fuller treatment of this taxonomy, see thevertebratearticle. The position ofhagfishin the phylum Chordata is not settled. Phylogenetic research in 1998 and 1999 supported the idea that the hagfish and the lampreys form a natural group, theCyclostomata, that is a sister group of the Gnathostomata.[17][18] The various fish groups account for more than half of vertebrate species. As of 2006,[19]there are almost 28,000 knownextantspecies, of which almost 27,000 are bony fish, with 970sharks, rays, and chimerasand about 108 hagfish and lampreys. A third of these species fall within the nine largest families; from largest to smallest, these families areCyprinidae,Gobiidae,Cichlidae,Characidae,Loricariidae,Balitoridae,Serranidae,Labridae, andScorpaenidae. About 64 families aremonotypic, containing only one species. The final total of extant species may grow to exceed 32,500.[20]Each year, newspeciesare discovered andscientifically described. As of 2016,[21]there are over 32,000 documented species of bony fish and over 1,100 species of cartilaginous fish. Species are lost throughextinction(seebiodiversity crisis). Recent examples are theChinese paddlefishor thesmooth handfish. Diversity Main article:Diversity of fish  Agnatha (Pacific hagfish)  Chondrichthyes (Horn shark)  Actinopterygii (Brown trout)  Sarcopterygii (Coelacanth)  A relative of the seahorses, theleafy seadragon's appendages allow it to camouflage (in the form ofcrypsis) with the surroundingseaweed.  The psychedelicmandarin dragonetis one of only two animal species known to have blue colouring because of cellular pigment.[22] The term "fish" most precisely describes any non-tetrapodcraniate(i.e. an animal with a skull and in most cases a backbone) that hasgillsthroughout life and whose limbs, if any, are in the shape of fins.[23]Unlike groupings such as birds ormammals, fish are not a singlecladebut aparaphyleticcollection oftaxa, includinghagfishes,lampreys,sharks and rays,ray-finned fish,coelacanths, andlungfish.[24][25]Indeed, lungfish and coelacanths are closer relatives oftetrapods(such as mammals, birds,amphibians, etc.) than of other fish such as ray-finned fish or sharks, so thelast common ancestorof all fish is also an ancestor to tetrapods. As paraphyletic groups are no longer recognised in modernsystematic biology, the use of the term "fish" as a biological group must be avoided. Many types ofaquatic animalscommonly referred to as "fish" are not fish in the sense given above; examples includeshellfish,cuttlefish,starfish,crayfishandjellyfish. In earlier times, even biologists did not make a distinction– sixteenth century natural historians classified alsoseals, whales,amphibians,crocodiles, evenhippopotamuses, as well as a host of aquatic invertebrates, as fish.[26]However, according to the definition above, all mammals, includingcetaceanslike whales and dolphins, are not fish. In some contexts, especially inaquaculture, the true fish are referred to asfinfish(orfin fish) to distinguish them from these other animals. A typical fish isectothermic, has astreamlinedbody for rapid swimming, extracts oxygen from water using gills or uses an accessory breathing organ to breathe atmospheric oxygen, has two sets of paired fins, usually one or two (rarely three) dorsal fins, an anal fin, and a tail fin, has jaws, has skin that is usually covered withscales, and lays eggs. Each criterion has exceptions.Tuna,swordfish, and some species ofsharksshowsome warm-blooded adaptations– they can heat their bodies significantly above ambient water temperature.[24]Streamlining and swimming performance varies from fish such as tuna,salmon, andjacksthat can cover 10–20 body-lengths per second to species such aseelsandraysthat swim no more than 0.5 body-lengths per second.[27]Many groups of freshwater fish extract oxygen from the air as well as from the water using a variety of different structures.Lungfishhave paired lungs similar to those of tetrapods,gouramishave a structure called thelabyrinth organthat performs a similar function, while many catfish, such asCorydorasextract oxygen via the intestine or stomach.[28]Body shape and the arrangement of the fins is highly variable, covering such seemingly un-fishlike forms asseahorses,pufferfish,anglerfish, andgulpers. Similarly, the surface of the skin may be naked (as inmoray eels), or covered with scales of a variety of different types usually defined asplacoid(typical of sharks and rays),cosmoid(fossil lungfish and coelacanths),ganoid(various fossil fish but also livinggarsandbichirs),cycloid, andctenoid(these last two are found on mostbony fish).[29]There are even fish that live mostly on land or lay their eggs on land near water.[30]Mudskippersfeed and interact with one another on mudflats and go underwater to hide in their burrows.[31]A singleundescribed speciesofPhreatobiushas been called a true "land fish" as this worm-like catfish strictly lives among waterloggedleaf litter.[32][33]Many species live inunderground lakes,underground riversoraquifersand are popularly known ascavefish.[34] Fish range in size from the huge 16-metre (52ft)whale sharkto the tiny 8-millimetre (0.3in)stout infantfish. Fishspeciesdiversity is roughly divided equally between marine (oceanic) andfreshwaterecosystems.Coral reefsin theIndo-Pacificconstitute the center of diversity for marine fishes, whereas continental freshwater fishes are most diverse in largeriver basinsoftropical rainforests, especially theAmazon,Congo, andMekongbasins. More than 5,600 fish species inhabitNeotropicalfreshwaters alone, such thatNeotropical fishesrepresent about 10% of allvertebratespecies on the Earth. Exceptionally rich sites in the Amazon basin, such asCantão State Park, can contain more freshwater fish species than occur in all of Europe.[35] The deepest living fish in the ocean so far found is the Mariana snailfish (Pseudoliparis swirei) which lives at deeps of 8,000 meters (26,200 feet) along the Mariana Trench near Guam.[36] Thediversityof living fish (finfish) is unevenly distributed among the various groups, withteleostsmaking up the bulk of living fishes (96%), and over 50% of allvertebratespecies.[21]The followingcladogram[37]shows theevolutionary relationshipsof all groups of living fishes (with their respective diversity[21]) and the four-limbed vertebrates (tetrapods).  Diversityof various groups of fish (and othervertebrates) through time  Lungfishare the closest living relatives oftetrapods(four-limbed vertebrates).  ThebowfinAmia calvais the sole survivor of thehalecomorphclade. Vertebrates  Jawless fish(118 living species:hagfish,lampreys)  Jawedvertebrates  Cartilaginous fishes(>1,100 living species:sharks,rays,chimaeras)  Bonyfishes Lobe-finfishRhipidistia  Tetrapoda(>30,000 living species:amphibians,mammals,reptiles,birds)    Dipnoi(6 living species:lungfish)     Actinistia(2 living species:coelacanths)   Ray-finfish  Cladistia(14 living species:bichirs,reedfish)  Actinopteri  Chondrostei(27 living species:sturgeons,paddlefish)  Neopterygii Holostei  Ginglymodi(7 living species:gars,alligator gars)    Halecomorphi(1 living species:bowfin)     Teleostei(>32,000 living species)           Anatomy and physiology Further information:Fish anatomyandFish physiology  Organs: 1.Liver, 2.Gas bladder, 3.Roe, 4.Pyloric caeca, 5.Stomach, 6.Intestine Respiration See also:Aquatic respiration Gills  Tunagills inside the head. The fish head is oriented snout-downwards, with the view looking towards the mouth. Most fish exchange gases usinggillson either side of thepharynx. Gills consist of threadlike structures calledfilaments. Each filament contains acapillarynetwork that provides a largesurface areafor exchangingoxygenandcarbon dioxide. Fish exchange gases by pulling oxygen-rich water through their mouths and pumping it over their gills. In some fish, capillary blood flows in the opposite direction to the water, causingcountercurrent exchange. The gills push the oxygen-poor water out through openings in the sides of the pharynx. Some fish, likesharksandlampreys, possess multiple gill openings. However,bony fishhave a single gill opening on each side. This opening is hidden beneath a protective bony cover called anoperculum. Juvenilebichirshave external gills, a very primitive feature that they share with larvalamphibians. Air breathing Fish from multiple groups can live out of the water for extended periods.Amphibious fishsuch as themudskippercan live and move about on land for up to several days,[dubious–discuss]or live in stagnant or otherwise oxygen depleted water. Many such fish can breathe air via a variety of mechanisms. The skin ofanguillid eelsmay absorb oxygen directly. Thebuccal cavityof theelectric eelmay breathe air. Catfish of the familiesLoricariidae,Callichthyidae, andScoloplacidaeabsorb air through their digestive tracts.[38]Lungfish, with the exception of theAustralian lungfish, andbichirshave paired lungs similar to those oftetrapodsand must surface to gulp fresh air through the mouth and pass spent air out through the gills.Garandbowfinhave a vascularized swim bladder that functions in the same way.Loaches,trahiras, and manycatfishbreathe by passing air through the gut. Mudskippers breathe by absorbing oxygen across the skin (similar to frogs). A number of fish have evolved so-called accessory breathing organs that extract oxygen from the air. Labyrinth fish (such asgouramisandbettas) have alabyrinth organabove the gills that performs this function. A few other fish have structures resembling labyrinth organs in form and function, most notablysnakeheads,pikeheads, and theClariidaecatfish family. Breathing air is primarily of use to fish that inhabit shallow, seasonally variable waters where the water's oxygen concentration may seasonally decline. Fish dependent solely on dissolved oxygen, such as perch andcichlids, quickly suffocate, while air-breathers survive for much longer, in some cases in water that is little more than wet mud. At the most extreme, some air-breathing fish are able to survive in damp burrows for weeks without water, entering a state ofaestivation(summertime hibernation) until water returns. Air breathing fish can be divided into obligate air breathers and facultative air breathers. Obligate air breathers, such as theAfrican lungfish,mustbreathe air periodically or they suffocate. Facultative air breathers, such as the catfishHypostomus plecostomus, only breathe air if they need to and will otherwise rely on their gills for oxygen. Most air breathing fish are facultative air breathers that avoid the energetic cost of rising to the surface and the fitness cost of exposure to surface predators.[38] Circulation  Didactic modelof a fish heart Fish have aclosed-loop circulatory system. Theheartpumps the blood in a single loop throughout the body. In most fish, the heart consists of four parts, including two chambers and an entrance and exit.[39]The first part is thesinus venosus, a thin-walled sac that collects blood from the fish'sveinsbefore allowing it to flow to the second part, theatrium, which is a large muscular chamber. The atrium serves as a one-way antechamber, sends blood to the third part,ventricle. The ventricle is another thick-walled, muscular chamber and it pumps the blood, first to the fourth part,bulbus arteriosus, a large tube, and then out of the heart. The bulbus arteriosus connects to theaorta, through which blood flows to the gills for oxygenation. Digestion Jaws allow fish to eat a wide variety of food, including plants and other organisms. Fish ingest food through the mouth and break it down in theesophagus. In the stomach, food is further digested and, in many fish, processed in finger-shaped pouches calledpyloric caeca, which secrete digestiveenzymesand absorb nutrients. Organs such as theliverandpancreasadd enzymes and various chemicals as the food moves through the digestive tract. The intestine completes the process of digestion and nutrient absorption. Excretion As with many aquatic animals, most fish release their nitrogenous wastes asammonia. Some of the wastesdiffusethrough the gills. Blood wastes arefilteredby thekidneys. Saltwater fish tend to lose water because ofosmosis. Their kidneys return water to the body. The reverse happens infreshwater fish: they tend to gain water osmotically. Their kidneys produce dilute urine for excretion. Some fish have specially adapted kidneys that vary in function, allowing them to move from freshwater to saltwater. Scales Main article:Fish scale The scales of fish originate from themesoderm(skin); they may be similar in structure to teeth. Sensory and nervous system  Dorsal view of the brain of therainbow trout Central nervous system Fish typically have quite small brains relative to body size compared with other vertebrates, typically one-fifteenth the brain mass of a similarly sized bird or mammal.[40]However, some fish have relatively large brains, most notablymormyridsandsharks, which have brains about as massive relative to body weight as birds andmarsupials.[41] Fish brains are divided into several regions. At the front are theolfactory lobes, a pair of structures that receive and process signals from thenostrilsvia the twoolfactory nerves.[40]The olfactory lobes are very large in fish that hunt primarily by smell, such as hagfish, sharks, and catfish. Behind the olfactory lobes is the two-lobedtelencephalon, the structural equivalent to thecerebruminhigher vertebrates. In fish the telencephalon is concerned mostly witholfaction.[40]Together these structures form the forebrain. Connecting the forebrain to the midbrain is thediencephalon(in the diagram, this structure is below the optic lobes and consequently not visible). The diencephalon performs functions associated withhormonesandhomeostasis.[40]Thepineal bodylies just above the diencephalon. This structure detects light, maintainscircadianrhythms, and controls color changes.[40] Themidbrain(or mesencephalon) contains the twooptic lobes. These are very large in species that hunt by sight, such asrainbow troutandcichlids.[40] The hindbrain (ormetencephalon) is particularly involved in swimming and balance.[40]The cerebellum is a single-lobed structure that is typically the biggest part of the brain.[40]Hagfish andlampreyshave relatively small cerebellae, while themormyridcerebellum is massive and apparently involved in theirelectrical sense.[40] The brain stem (ormyelencephalon) is the brain's posterior.[40]As well as controlling some muscles and body organs, in bony fish at least, the brain stem governsrespirationandosmoregulation.[40] Sense organs Main article:Sensory systems in fish Most fish possess highly developed sense organs. Nearly all daylight fish have color vision that is at least as good as a human's (seevision in fishes). Many fish also have chemoreceptors that are responsible for extraordinary senses of taste and smell. Although they have ears, many fish may not hear very well. Most fish have sensitive receptors that form thelateral line system, which detects gentle currents and vibrations, and senses the motion of nearby fish and prey.[42]The sense information obtained from the lateral line system can be considered both a sense oftouchandhearing.Blind cave fishnavigate almost entirely through the sensations from their lateral line system.[43]Some fish, such as catfish and sharks, have theampullae of Lorenzini,electroreceptorsthat detect weak electric currents on the order of millivolt.[44]Other fish, like the South American electric fishesGymnotiformes, can produce weak electric currents, which they use in navigation and social communication. Fish orient themselves using landmarks and may use mental maps based on multiple landmarks or symbols. Fish behavior in mazes reveals that they possess spatial memory and visual discrimination.[45] Vision Main article:Vision in fishes Visionis an importantsensory systemfor most species of fish. Fish eyes are similar to those ofterrestrialvertebrateslikebirdsand mammals, but have a moresphericallens. Theirretinasgenerally have bothrodsandcones(forscotopicandphotopic vision), and most species havecolour vision. Some fish can seeultravioletand some can seepolarized light. Amongstjawless fish, thelampreyhas well-developed eyes, while thehagfishhas only primitiveeyespots.[46]Fish vision showsadaptationto their visual environment, for exampledeep sea fisheshave eyes suited to the dark environment. Hearing See also:Hearing in fish Hearingis an important sensory system for most species of fish. Fish sense sound using theirlateral linesand theirears. Cognition Further information:Fish intelligence New research has expanded preconceptions about the cognitive capacities of fish. For example,manta rayshave exhibited behavior linked toself-awarenessinmirror testcases. Placed in front of a mirror, individual rays engaged in contingency testing, that is, repetitive behavior aiming to check whether their reflection's behavior mimics their body movement.[47] Wrasseshave also passed the mirror test in a 2018 scientific study.[48][49] Cases of tool use have also been noticed, notably in theChoerodonfamily, inarcherfishandAtlantic cod.[50] Capacity for pain Further information:Pain in fish Experiments done by William Tavolga provide evidence that fish havepainand fear responses. For instance, in Tavolga's experiments,toadfishgrunted when electrically shocked and over time they came to grunt at the mere sight of an electrode.[51] In 2003, Scottish scientists at theUniversity of Edinburghand the Roslin Institute concluded that rainbow trout exhibit behaviors often associated withpainin other animals.Beevenomandacetic acidinjected into the lips resulted in fish rocking their bodies and rubbing their lips along the sides and floors of their tanks, which the researchers concluded were attempts to relieve pain, similar to what mammals would do.[52][53]Neurons fired in a pattern resembling human neuronal patterns.[53] Professor James D. Rose of theUniversity of Wyomingclaimed the study was flawed since it did not provide proof that fish possess "conscious awareness, particularly a kind of awareness that is meaningfully like ours".[54]Rose argues that since fish brains are so different from human brains, fish are probably not conscious in the manner humans are, so that reactions similar to human reactions to pain instead have other causes. Rose had published a study a year earlier arguing that fish cannot feel pain because their brains lack aneocortex.[55]However, animal behavioristTemple Grandinargues that fish could still have consciousness without a neocortex because "different species can use different brain structures and systems to handle the same functions."[53] Animal welfare advocates raise concerns about the possiblesufferingof fish caused by angling. Some countries, such as Germany, have banned specific types of fishing, and the BritishRSPCAnow formally prosecutes individuals who are cruel to fish.[56] Emotion In 2019, scientists have shown that members of themonogamousspeciesAmatitlania siquiaexhibit pessimistic behavior when they are prevented from being with their partner.[57] Muscular system Main article:Fish locomotion  The anatomy ofLampanyctodes hectoris(1)operculum (gill cover), (2)lateral line, (3)dorsal fin, (4)fat fin, (5)caudal peduncle, (6)caudal fin, (7)anal fin, (8)photophores, (9)pelvic fins (paired), (10)pectoral fins (paired)  Swim bladder of a rudd (Scardinius erythrophthalmus) Most fish move by alternately contracting paired sets of muscles on either side of the backbone. These contractions form S-shaped curves that move down the body. As each curve reaches the back fin, backward force is applied to the water, and in conjunction with the fins, moves the fish forward. The fish's fins function like an airplane's flaps. Fins also increase the tail's surface area, increasing speed. The streamlined body of the fish decreases the amount of friction from the water. Since body tissue is denser than water, fish must compensate for the difference or they will sink. Many bony fish have an internal organ called aswim bladderthat adjusts their buoyancy through manipulation of gases. Endothermy Although most fish are exclusivelyectothermic, there are exceptions. The only known bony fishes (infraclassTeleostei) that exhibitendothermyare in the suborderScombroidei– which includes thebillfishes, tunas, and thebutterfly kingfish, abasalspecies of mackerel[58]– and also theopah. The opah, alampriform, was demonstrated in 2015 to utilize "whole-body endothermy", generating heat with its swimming muscles to warm its body while countercurrent exchange (as in respiration) minimizes heat loss.[59]It is able to actively hunt prey such as squid and swim for long distances due to the ability to warm its entire body, including its heart,[60]which is a trait typically found in only mammals and birds (in the form ofhomeothermy). In the cartilaginous fishes (classChondrichthyes), sharks of the familiesLamnidae(porbeagle, mackerel, salmon, and great white sharks) andAlopiidae(thresher sharks) exhibit endothermy. The degree of endothermy varies from the billfishes, which warm only their eyes and brain, to thebluefin tunaand theporbeagle shark, which maintain body temperatures in excess of 20°C (68°F) above ambient water temperatures.[58] Endothermy, though metabolically costly, is thought to provide advantages such as increased muscle strength, higher rates of centralnervous systemprocessing, and higher rates ofdigestion. Reproductive system Further information:Fish reproductionandSpawn (biology)  Ovary of fish (Corumbatá) Fish reproductive organs includetesticlesandovaries. In most species, gonads are paired organs of similar size, which can be partially or totally fused.[61]There may also be a range of secondary organs that increase reproductive fitness. In terms ofspermatogoniadistribution, the structure ofteleoststestes has two types: in the most common, spermatogonia occur all along theseminiferous tubules, while inatherinomorphfish they are confined to thedistalportion of these structures. Fish can present cystic or semi-cysticspermatogenesisin relation to the release phase of germ cells in cysts to the seminiferous tubuleslumen.[61] Fish ovaries may be of three types: gymnovarian, secondary gymnovarian or cystovarian. In the first type, theoocytesare released directly into thecoelomiccavity and then enter theostium, then through theoviductand are eliminated. Secondary gymnovarian ovaries shedovainto the coelom from which they go directly into the oviduct. In the third type, the oocytes are conveyed to the exterior through the oviduct.[62]Gymnovaries are the primitive condition found inlungfish,sturgeon, andbowfin. Cystovaries characterize most teleosts, where the ovary lumen has continuity with the oviduct.[61]Secondary gymnovaries are found insalmonidsand a few other teleosts. Oogoniadevelopment in teleosts fish varies according to the group, and the determination of oogenesis dynamics allows the understanding of maturation and fertilization processes. Changes in thenucleus, ooplasm, and the surrounding layers characterize the oocyte maturation process.[61] Postovulatoryfolliclesare structures formed after oocyte release; they do not haveendocrinefunction, present a wide irregular lumen, and are rapidly reabsorbed in a process involving theapoptosisof follicular cells. A degenerative process calledfollicular atresiareabsorbs vitellogenic oocytes not spawned. This process can also occur, but less frequently, in oocytes in other development stages.[61] Some fish, like theCalifornia sheephead, arehermaphrodites, having both testes and ovaries either at different phases in their life cycle or, as inhamlets, have them simultaneously. Over 97% of all known fish areoviparous,[63]that is, the eggs develop outside the mother's body. Examples of oviparous fish includesalmon,goldfish,cichlids,tuna, andeels. In the majority of these species, fertilisation takes place outside the mother's body, with the male and female fish shedding theirgametesinto the surrounding water. However, a few oviparous fish practice internal fertilization, with the male using some sort ofintromittent organto deliver sperm into the genital opening of the female, most notably the oviparous sharks, such as thehorn shark, and oviparous rays, such asskates. In these cases, the male is equipped with a pair of modifiedpelvic finsknown asclaspers. Marine fish can produce high numbers of eggs which are often released into the open water column. The eggs have an average diameter of 1 millimetre (0.04in).  Egg oflamprey  Egg ofcatshark(mermaids' purse)  Egg ofbullhead shark  Egg ofchimaera The newly hatched young of oviparous fish are calledlarvae. They are usually poorly formed, carry a largeyolk sac(for nourishment), and are very different in appearance from juvenile and adult specimens. The larval period in oviparous fish is relatively short (usually only several weeks), and larvae rapidly grow and change appearance and structure (a process termedmetamorphosis) to become juveniles. During this transition larvae must switch from their yolk sac to feeding onzooplanktonprey, a process which depends on typically inadequate zooplankton density, starving many larvae. Inovoviviparousfish the eggs develop inside the mother's body after internal fertilization but receive little or no nourishment directly from the mother, depending instead on theyolk. Each embryo develops in its own egg. Familiar examples of ovoviviparous fish includeguppies,angel sharks, andcoelacanths. Some species of fish areviviparous. In such species the mother retains the eggs and nourishes the embryos. Typically, viviparous fish have a structure analogous to theplacentaseen inmammalsconnecting the mother's blood supply with that of the embryo. Examples of viviparous fish include thesurf-perches,splitfins, andlemon shark. Some viviparous fish exhibitoophagy, in which the developing embryos eat other eggs produced by the mother. This has been observed primarily among sharks, such as theshortfin makoandporbeagle, but is known for a few bony fish as well, such as thehalfbeakNomorhamphus ebrardtii.[64]Intrauterine cannibalismis an even more unusual mode of vivipary, in which the largest embryos eat weaker and smaller siblings. This behavior is also most commonly found among sharks, such as thegrey nurse shark, but has also been reported forNomorhamphus ebrardtii.[64] Aquaristscommonly refer to ovoviviparous and viviparous fish aslivebearers. Acoustic communication See also:Acoustic communication in aquatic animals Acoustic communication in fish involves the transmission of acoustic signals from one individual of a species to another. The production of sounds as a means of communication among fish is most often used in the context of feeding, aggression or courtship behaviour.[3]The sounds emitted can vary depending on the species and stimulus involved. Fish can produce either stridulatory sounds by moving components of the skeletal system, or can produce non-stridulatory sounds by manipulating specialized organs such as the swimbladder.[65] Stridulatory  French grunts –Haemulon flavolineatum There are some species of fish that can produce sounds by rubbing or grinding their bones together. These noises produced by bone-on-bone interactions are known as 'stridulatory sounds'.[65] An example of this is seen inHaemulon flavolineatum, a species commonly referred to as the 'French grunt fish', as it produces a grunting noise by grinding its teeth together.[65]This behaviour is most pronounced when theH. flavolineatumis in distress situations.[65]The grunts produced by this species of fishes generate a frequency of approximately 700Hz, and last approximately 47 milliseconds.[65]TheH. flavolineatumdoes not emit sounds with frequencies greater than 1000Hz, and does not detect sounds that have frequencies greater than 1050Hz.[65] In a study conducted by Oliveira et al. (2014), the longsnout seahorse,Hippocampus reidi, was recorded producing two different categories of sounds; 'clicks' and 'growls'. The sounds emitted by theH. reidiare accomplished by rubbing their coronet bone across the grooved section of their neurocranium.[66]'Clicking' sounds were found to be primarily produced during courtship and feeding, and the frequencies of clicks were within the range of 50Hz-800Hz.[67]The frequencies were noted to be on the higher end of the range during spawning periods, when the female and male fishes were less than fifteen centimeters apart.[67]Growl sounds were produced when theH. reidiencountered stressful situations, such as handling by researchers.[67]The 'growl' sounds consist of a series of sound pulses and are emitted simultaneously with body vibrations.[67] Non-stridulatory  Oyster toadfish Some fish species create noise by engaging specialized muscles that contract and cause swimbladder vibrations. Oyster toadfishproduce loud grunting sounds by contracting muscles located along the sides of their swim bladder, known as sonic muscles[68]Female and male toadfishes emit short-duration grunts, often as a fright response.[69]In addition to short-duration grunts, male toadfishes produce "boat whistle calls".[70]These calls are longer in duration, lower in frequency, and are primarily used to attract mates.[70]The sounds emitted by theO. taohave frequency range of 140Hz to 260Hz.[70]The frequencies of the calls depend on the rate at which the sonic muscles contract.[71][68] The red drum,Sciaenops ocellatus, produces drumming sounds by vibrating its swimbladder.[72]Vibrations are caused by the rapid contraction of sonic muscles that surround the dorsal aspect of the swimbladder.[72]These vibrations result in repeated sounds with frequencies that range from 100 to >200Hz.[72]TheS. ocellatuscan produce different calls depending on the stimuli involved.[72]The sounds created in courtship situations are different from those made during distressing events such as predatorial attacks.[72]Unlike the males of theS. ocellatusspecies, the females of this species do not produce sounds and lack sound-producing (sonic) muscles.[72] Diseases Main article:Fish diseases and parasites Like other animals, fish suffer from diseases and parasites. To prevent disease they have a variety of defenses.Non-specificdefenses include the skin and scales, as well as the mucus layer secreted by theepidermisthat traps and inhibits the growth ofmicroorganisms. Ifpathogensbreach these defenses, fish can develop aninflammatory responsethat increases blood flow to the infected region and deliverswhite blood cellsthat attempt to destroy pathogens. Specific defenses respond to particular pathogens recognised by the fish's body, i.e., animmune response.[73]In recent years,vaccineshave become widely used in aquaculture and also with ornamental fish, for examplefurunculosisvaccines in farmedsalmonandkoi herpes virusinkoi.[74][75] Some species usecleaner fishto remove external parasites. The best known of these are thebluestreak cleaner wrassesof the genusLabroidesfound oncoral reefsin theIndianandPacificoceans. These small fish maintain so-called "cleaning stations" where other fish congregate and perform specific movements to attract the attention of the cleaners.[76]Cleaning behaviors have been observed in a number of fish groups, including an interesting case between two cichlids of the same genus,Etroplus maculatus, the cleaner, and the much largerEtroplus suratensis.[77] Immune system Immune organs vary by type of fish.[78]In thejawless fish(lampreys and hagfish), truelymphoidorgans are absent. These fish rely on regions oflymphoid tissuewithin other organs to produce immune cells. For example,erythrocytes,macrophagesandplasma cellsare produced in the anterior kidney (orpronephros) and some areas of the gut (wheregranulocytesmature.) They resemble primitivebone marrowin hagfish.Cartilaginous fish(sharks and rays) have a more advanced immune system. They have three specialized organs that are unique toChondrichthyes; the epigonal organs (lymphoid tissue similar to mammalian bone) that surround the gonads, theLeydig's organwithin the walls of their esophagus, and aspiral valvein their intestine. These organs house typical immune cells (granulocytes, lymphocytes and plasma cells). They also possess an identifiablethymusand a well-developedspleen(their most important immune organ) where variouslymphocytes, plasma cells and macrophages develop and are stored.Chondrosteanfish (sturgeons, paddlefish, and bichirs) possess a major site for the production of granulocytes within a mass that is associated with themeninges(membranes surrounding the central nervous system.) Their heart is frequently covered with tissue that contains lymphocytes,reticular cellsand a small number ofmacrophages. The chondrostean kidney is an importanthemopoieticorgan; where erythrocytes, granulocytes, lymphocytes and macrophages develop. Like chondrostean fish, the major immune tissues of bony fish (orteleostei) include the kidney (especially the anterior kidney), which houses many different immune cells.[79]In addition, teleost fish possess a thymus, spleen and scattered immune areas within mucosal tissues (e.g. in the skin, gills, gut and gonads). Much like the mammalian immune system, teleost erythrocytes, neutrophils and granulocytes are believed to reside in the spleen whereas lymphocytes are the major cell type found in the thymus.[80][81]In 2006, a lymphatic system similar to that in mammals was described in one species of teleost fish, thezebrafish. Although not confirmed as yet, this system presumably will be where naive (unstimulated)T cellsaccumulate while waiting to encounter anantigen.[82] B and T lymphocytes bearingimmunoglobulinsandT cell receptors, respectively, are found in all jawed fishes. Indeed, theadaptive immune systemas a wholeevolvedin an ancestor of all jawed vertebrates.[83] Conservation The 2006IUCNRed Listnames 1,173 fish species that are threatened with extinction.[84]Included are species such asAtlantic cod,[85]Devil's Hole pupfish,[86]coelacanths,[87]andgreat white sharks.[88]Because fish live underwater they are more difficult to study than terrestrial animals and plants, and information about fish populations is often lacking. However, freshwater fish seem particularly threatened because they often live in relatively small water bodies. For example, theDevil's Hole pupfishoccupies only a single 3 by 6 metres (10 by 20ft) pool.[89] Overfishing  Whale sharks, the largest species of fish, are classified asvulnerable. Main article:Overfishing Overfishing is a major threat to edible fish such as cod andtuna.[90][91]Overfishing eventually causespopulation(known asstock) collapse because the survivors cannot produce enough young to replace those removed. Suchcommercial extinctiondoes not mean that the species is extinct, merely that it can no longer sustain a fishery. One well-studied example of fishery collapse is thePacific sardineSadinops sagax caeruluesfishery off the California coast. From a 1937 peak of 790,000 long tons (800,000t) the catch steadily declined to only 24,000 long tons (24,000t) in 1968, after which the fishery was no longer economically viable.[92] The main tension betweenfisheries scienceand thefishing industryis that the two groups have different views on the resiliency of fisheries to intensive fishing. In places such as Scotland, Newfoundland, and Alaska the fishing industry is a major employer, so governments are predisposed to support it.[93][94]On the other hand, scientists and conservationists push for stringent protection, warning that many stocks could be wiped out within fifty years.[95][96] Habitat destruction See also:Environmental impact of fishing A key stress on both freshwater and marine ecosystems is habitat degradation includingwater pollution, the building of dams, removal of water for use by humans, and the introduction ofexoticspecies.[97]An example of a fish that has become endangered because of habitat change is thepallid sturgeon, a North American freshwater fish that lives in rivers damaged by human activity.[98] Exotic species Introduction ofnon-nativespecies has occurred in many habitats. One of the best studied examples is the introduction ofNile perchintoLake Victoriain the 1960s. Nile perch gradually exterminated the lake's 500endemiccichlidspecies. Some of them survive now in captive breeding programmes, but others are probably extinct.[99]Carp,snakeheads,[100]tilapia,European perch,brown trout,rainbow trout, andsea lampreysare other examples of fish that have caused problems by being introduced into alien environments. Importance to humans Economic Main articles:Fishing industry,Aquaculture, andFish farming  These fish-farming ponds were created as acooperativeproject in a rural village. Throughout history, humans have utilizedfish as a food source. Historically and today, most fishproteinhas come by means of catching wild fish. However, aquaculture, or fish farming, which has been practiced since about 3,500 BCE. in China,[101]is becoming increasingly important in many nations. Overall, about one-sixth of the world's protein is estimated to be provided by fish.[102]That proportion is considerably elevated in somedeveloping nationsand regions heavily dependent on the sea. In a similar manner, fish have been tied to trade.  Fish counter display at theOulu Market HallinOulu, Finland. Catching fish for the purpose of food or sport is known asfishing, while the organized effort by humans to catch fish is called afishery. Fisheries are a huge global business and provide income for millions of people.[102]The annual yield from all fisheries worldwide is about 154 million tons,[103]with popular species includingherring,cod,anchovy,tuna,flounder, andsalmon. However, the term fishery is broadly applied, and includes more organisms than just fish, such asmollusksandcrustaceans, which are often called "fish" when used as food. Recreation  ABengalifish vendor Main articles:Fishkeeping,Recreational fishing, andAngling Fishkeeping Fish have been recognized as a source of beauty for almost as long as used for food, appearing incave art, being raised asornamental fishin ponds, and displayed inaquariumsin homes, offices, or public settings. Recreational fishing Recreational fishingis fishing primarily for pleasure or competition; it can be contrasted withcommercial fishing, which is fishing for profit, orartisanal fishing, which is fishing primarily for food. The most common form of recreational fishing is done with arod,reel,line,hooks, and any one of a wide range ofbaits. Recreational fishing is particularly popular in North America and Europe and state, provincial, and federal government agencies actively management target fish species.[104][105]Angling is a method of fishing, specifically the practice of catching fish by means of an "angle" (hook). Anglers must select the right hook,castaccurately, and retrieve at the right speed while considering water and weather conditions, species, fish response, time of the day, and other factors. Culture Main article:Fish in culture  AvatarofVishnuas aMatsya Fish themes have symbolic significance in many religions. In ancientMesopotamia, fish offerings were made to the gods from the very earliest times.[106]Fish were also a major symbol ofEnki, the god of water.[106]Fish frequently appear as filling motifs incylinder sealsfrom theOld Babylonian(c.1830 BC –c.1531 BC) andNeo-Assyrian(911–609 BC) periods.[106]Starting during theKassite Period(c.1600 BC –c.1155 BC) and lasting until the earlyPersian Period(550–30 BC), healers and exorcists dressed in ritual garb resembling the bodies of fish.[106]During theSeleucid Period(312–63 BC), the legendary Babylonianculture heroOannes, described byBerossus, was said to have dressed in the skin of a fish.[106]Fish were sacred to the Syrian goddessAtargatis[107]and, during her festivals, only her priests were permitted to eat them.[107]  Theichthusis a Christian symbol of a fish signifying that the person who uses it is a Christian.[107][108] In theBook of Jonah, a work of Jewish literature probably written in the fourth century BC, the central figure, aprophetnamedJonah, is swallowed by a giant fish after being thrown overboard by the crew of the ship he is travelling on.[109][110][111]The fish later vomits Jonah out on shore after three days.[109][110][111]This book was later included as part of theHebrew Bible, or ChristianOld Testament,[112][113]and a version of the story it contains is summarized inSurah37:139-148 of theQuran.[114]Early Christiansused theichthys, a symbol of a fish, to represent Jesus,[107][108]because the Greek word for fish, ΙΧΘΥΣ Ichthys, could be used as an acronym for "Ίησοῦς Χριστός, Θεοῦ Υἱός, Σωτήρ" (Iesous Christos, Theou Huios, Soter), meaning "Jesus Christ, Son of God, Saviour".[107][108]Thegospelsalso refer to "fishers of men"[115]andfeeding the multitude. In thedhammaofBuddhism, the fish symbolize happiness as they have complete freedom of movement in the water. Often drawn in the form ofcarpwhich are regarded in the Orient as sacred on account of their elegant beauty, size and life-span. Among thedeitiessaid to take the form of a fish areIka-Roaof thePolynesians,Dagonof various ancientSemitic peoples, the shark-gods ofHawaiʻiandMatsyaof the Hindus. TheastrologicalsymbolPiscesis based on a constellation of thesame name, but there is also a second fish constellation in the night sky,Piscis Austrinus.[116] Fish feature prominently in art and literature, in movies such asFinding Nemoand books such asThe Old Man and the Sea. Large fish, particularly sharks, have frequently been the subject ofhorror moviesandthrillers, most notably the novelJaws, which spawned a series of films of thesame namethat in turn inspired similar films or parodies such asShark TaleandSnakehead Terror. Piranhas are shown in a similar light to sharks in films such asPiranha; however, contrary to popular belief, thered-bellied piranhais actually a generally timid scavenger species that is unlikely to harm humans.[117]Legends of half-human, half-fishmermaidshave featured in folklore, including the stories ofHans Christian Andersen. Terminology "Fish" or "fishes" Though often used interchangeably, in biology these words have different meanings.Fishis used as a singular noun, or as a plural to describe multiple individuals from a single species.Fishesis used to describe different species or species groups.[118][119][120]Thus a pond would be said to contain 120 fish if all were from a single species or 120 fishes if these included a mix of several species. The distinction is similar to that between people and peoples. "True fish" or "finfish" In biology, the termfishis most strictly used to describe any animal with abackbone,gillsthroughout life, and limbs (if any) in the shape offins.[23]Many types ofaquatic animalswith common names ending in "fish" are not fish in thissense; examples includeshellfish,cuttlefish,starfish,crayfishandjellyfish. In earlier times, even biologists did not make a distinction– sixteenth century natural historians classified alsoseals, whales,amphibians,crocodiles, evenhippopotamuses, as well as a host of aquatic invertebrates, as fish.[26] In fisheries, the termfishis used as a collective term, and includesmollusks,crustaceansand anyaquatic animalwhich is harvested.[121] The strict biological definition of a fish, above, is sometimes called atrue fish. True fish are also referred to asfinfishorfin fishto distinguish them from other aquatic life harvested in fisheries or aquaculture. "Shoal" or "school" Main article:Shoaling and schooling  Thesegoldband fusiliersareschoolingbecause their swimming is synchronised. An assemblage of fish merely using some localised resource such as food or nesting sites is known simply as anaggregation. When fish come together in an interactive, social grouping, then they may be forming either ashoalor aschooldepending on the degree of organisation. Ashoalis a loosely organised group where each fish swims and forages independently but is attracted to other members of the group and adjusts its behaviour, such as swimming speed, so that it remains close to the other members of the group.Schoolsof fish are much more tightly organised, synchronising their swimming so that all fish move at the same speed and in the same direction. Shoaling and schooling behaviour is believed to provide a variety of advantages.[122] Examples: Cichlids congregating atlekkingsites form anaggregation. Many minnows and characins formshoals. Anchovies, herrings and silversides are classic examples ofschoolingfish. The most common collective nouns for a group of fish in general are school and shoal. Both the words have evolved from the same common Dutch root 'schole' meaning a troop or crowd. While the words "school" and "shoal" have different meanings within biology, the distinctions are often ignored by non-specialists who treat the words assynonyms. Thus speakers ofBritish Englishcommonly use "shoal" to describe any grouping of fish, and speakers ofAmerican Englishcommonly use "school" just as loosely.[123]

Very Angry Lynx. Lynx have a short tail, characteristic tufts of black hair on the tips of their ears, large, padded paws for walking on snow and long whiskers on the face. Under their neck, they have a ruff, which has black bars resembling a bow tie, although this is often not visible. Body colour varies from medium brown to goldish to beige-white, and is occasionally marked with dark brown spots, especially on the limbs. All species of lynx have white fur on their chests, bellies and on the insides of their legs, fur which is an extension of the chest and belly fur. The lynx's colouring, fur length and paw size vary according to the climate in their range. In the Southwestern United States, they are short-haired, dark in colour and their paws are smaller and less padded. As climates get colder and more northerly, lynx have progressively thicker fur, lighter colour, and their paws are larger and more padded to adapt to the snow. Their paws may be larger than a human hand or foot. The smallest species are the bobcat and the Canada lynx, while the largest is the Eurasian lynx, with considerable variations within species.

Deerortrue deerarehoofedruminantmammalsforming thefamilyCervidae. The two main groups of deer are theCervinae, including themuntjac, theelk(wapiti), thered deer, and thefallow deer; and theCapreolinae, including thereindeer(caribou),white-tailed deer, theroe deer, and themoose. Male deer of all species (except thewater deer) as well as female reindeer, grow and shed newantlerseach year. In this they differ from permanentlyhornedantelope, which are part of a different family (Bovidae) within the same order ofeven-toed ungulates(Artiodactyla). Deer[1] Temporal range:Early Oligocene–Recent PreꞒ Ꞓ O S D C P T J K Pg N Images of a few members of the family Cervidae (counterclockwise from top left): theelk(Cervus canadensis),white-tailed deer(Odocoileus virginianus),grey brocket(Mazama gouazoubira),barasingha(Rucervus duvaucelii),pudú(Genus:Pudu),sika deer(Cervus nippon),red deer(Cervus elaphus), andreindeer(Rangifer tarandus)Scientific classificationKingdom:AnimaliaPhylum:ChordataClass:MammaliaOrder:ArtiodactylaInfraorder:PecoraFamily:Cervidae Goldfuss, 1820Type genusCervus Linnaeus, 1758 Subfamilies Capreolinae Cervinae Combined native range of all species of deer. Themusk deer(Moschidae) of Asia andchevrotains(Tragulidae) of tropical African and Asian forests are separate families that are also in the ruminant cladeRuminantia; they are not especially closely related to Cervidae. Deer appear in art fromPaleolithiccave paintingsonwards, and they haveplayed a role in mythology, religion, and literature throughout history, as well as inheraldry, such as red deer that appear in thecoat of arms of Åland.[2]Their economic importance includes the use of their meat asvenison, their skins as soft, strongbuckskin, and their antlers as handles for knives. Deerhuntinghas been a popular activity since the Middle Ages and remains a resource for many families today. Contents Etymology and terminologyEdit  "The Stag Hunt ofFrederick III, Elector of Saxony" byLucas Cranach the Elder, 1529 The worddeerwas originally broad in meaning, becoming more specific with time.Old EnglishdēorandMiddle Englishdermeant a wild animal of any kind. Cognates of Old Englishdēorin other deadGermanic languageshave the general sense ofanimal, such asOld High Germantior,Old Norsedjurordȳr,Gothicdius,Old Saxondier, andOld Frisiandiar.[3]This general sense gave way to the modern English sense by the end of the Middle English period, around 1500. All modern Germanic languages save English and Scots retain the more general sense: for example, GermanTierand Norwegiandyrmeananimal.[4] For many types of deer in modern English usage, the male is abuckand the female adoe, but the terms vary with dialect, and according to the size of the species. The malered deeris astag, while for other large species the male is abull, the female acow, as in cattle. In older usage, the male of any species is ahart, especially if over five years old, and the female is ahind, especially if three or more years old.[5]The young of small species is afawnand of large species acalf; a very small young may be akid. A castrated male is ahavier.[6]A group of any species is aherd. Theadjectiveof relation iscervine; like the family nameCervidae, this is fromLatin:cervus, meaningstagordeer. DistributionEdit  Chitaldeer inNagarahole, India Deer live in a variety ofbiomes, ranging fromtundrato thetropical rainforest. While often associated with forests, many deer areecotonespecies that live in transitional areas between forests and thickets (for cover) and prairie and savanna (open space). The majority of large deer species inhabit temperate mixed deciduous forest, mountain mixed coniferous forest, tropical seasonal/dry forest, and savanna habitats around the world. Clearing open areas within forests to some extent may actually benefit deer populations by exposing theunderstoryand allowing the types of grasses, weeds, and herbs to grow that deer like to eat. Access to adjacent croplands may also benefit deer. Adequate forest or brush cover must still be provided for populations to grow and thrive. Deer are widely distributed, with indigenous representatives in all continents exceptAntarcticaandAustralia, thoughAfricahas only one native deer, theBarbary stag, a subspecies ofred deerthat is confined to theAtlas Mountainsin the northwest of the continent. Another extinct species of deer,Megaceroides algericus,was present inNorth Africauntil 6000 years ago.Fallow deerhave been introduced toSouth Africa. Small species ofbrocket deerandpudúsofCentralandSouth America, andmuntjacsofAsiagenerally occupy dense forests and are less often seen in open spaces, with the possible exception of theIndian muntjac. There are also several species of deer that are highly specialized and live almost exclusively in mountains, grasslands, swamps, and "wet" savannas, orriparian corridorssurrounded bydeserts. Some deer have a circumpolar distribution in bothNorth AmericaandEurasia. Examples include thecaribouthat live in Arctictundraandtaiga(boreal forests) andmoosethat inhabit taiga and adjacent areas. Huemul deer (tarucaandChilean huemul) ofSouth America'sAndesfill the ecological niches of theibexandwild goat, with the fawns behaving more likegoatkids. The highest concentration of large deer species in temperate North America lies in theCanadian Rocky MountainandColumbia Mountainregions between Alberta and British Columbia where all five North American deer species (white-tailed deer,mule deer,caribou,elk, andmoose) can be found. This region has several clusters of national parks includingMount Revelstoke National Park,Glacier National Park (Canada),Yoho National Park, andKootenay National Parkon the British Columbia side, andBanff National Park,Jasper National Park, andGlacier National Park (U.S.)on the Alberta and Montana sides. Mountain slope habitats vary from moist coniferous/mixed forested habitats to dry subalpine/pine forests with alpine meadows higher up. The foothills and river valleys between the mountain ranges provide a mosaic of cropland and deciduous parklands. The rare woodland caribou have the most restricted range living at higher altitudes in the subalpine meadows andalpine tundraareas of some of the mountain ranges. Elk and mule deer both migrate between the alpine meadows and lower coniferous forests and tend to be most common in this region. Elk also inhabit river valley bottomlands, which they share with White-tailed deer. The White-tailed deer have recently expanded their range within the foothills and river valley bottoms of the Canadian Rockies owing to conversion of land to cropland and the clearing of coniferous forests allowing more deciduous vegetation to grow up the mountain slopes. They also live in the aspen parklands north of Calgary and Edmonton, where they share habitat with the moose. The adjacentGreat Plainsgrassland habitats are left to herds of elk,American bison, andpronghorn.  Reindeerherds standing on snow to avoid flies TheEurasianContinent (including the Indian Subcontinent) boasts the most species of deer in the world, with most species being found in Asia. Europe, in comparison, has lower diversity in plant and animal species. Many national parks and protected reserves in Europe have populations of red deer,roe deer, and fallow deer. These species have long been associated with the continent of Europe, but also inhabitAsia Minor, theCaucasus Mountains, and NorthwesternIran. "European" fallow deer historically lived over much of Europe during the Ice Ages, but afterwards became restricted primarily to the Anatolian Peninsula, in present-day Turkey. Present-day fallow deer populations in Europe are a result of historic man-made introductions of this species, first to the Mediterranean regions of Europe, then eventually to the rest of Europe. They were initially park animals that later escaped and reestablished themselves in the wild. Historically, Europe's deer species shared their deciduous forest habitat with other herbivores, such as the extincttarpan(forest horse), extinctaurochs(forest ox), and the endangeredwisent(European bison). Good places to see deer in Europe include theScottish Highlands, theAustrianAlps, thewetlandsbetweenAustria,Hungary, and theCzech Republic, and some National Parks, includingDoñana National ParkinSpain, theVeluwein theNetherlands, theArdennesinBelgium, andBiałowieża National ParkinPoland.Spain,Eastern Europe, and theCaucasus Mountainshave forest areas that are not only home to sizable deer populations but also other animals that were once abundant such as the wisent,Eurasian lynx,Iberian lynx,wolves, andbrown bears.  Somesika deer(Cervus nippon) andJapanese macaques(Macaca fuscata) along a waterside The highest concentration of large deer species in temperate Asia occurs in the mixed deciduous forests, mountain coniferous forests, and taiga bordering North Korea, Manchuria (Northeastern China), and the Ussuri Region (Russia). These are among some of the richest deciduous and coniferous forests in the world where one can findSiberian roe deer,sika deer, elk, and moose. Asian caribou occupy the northern fringes of this region along the Sino-Russian border. Deer such as the sika deer,Thorold's deer,Central Asian red deer, and elk have historically been farmed for their antlers byHan Chinese,Turkic peoples,Tungusic peoples,Mongolians, andKoreans. Like theSami peopleof Finland and Scandinavia, the Tungusic peoples, Mongolians, and Turkic peoples of Southern Siberia, Northern Mongolia, and the Ussuri Region have also taken to raising semi-domesticated herds of Asian caribou. The highest concentration of large deer species in the tropics occurs in Southern Asia in India's Indo-Gangetic Plain Region andNepal's Terai Region. These fertile plains consist of tropical seasonal moist deciduous, dry deciduous forests, and both dry and wet savannas that are home tochital,hog deer,barasingha, Indiansambar, andIndian muntjac. Grazing species such as the endangered barasingha and very common chital are gregarious and live in large herds. Indian sambar can be gregarious but are usually solitary or live in smaller herds. Hog deer are solitary and have lower densities than Indian muntjac. Deer can be seen in several national parks in India, Nepal, and Sri Lanka of whichKanha National Park,Dudhwa National Park, andChitwan National Parkare most famous. Sri Lanka'sWilpattu National ParkandYala National Parkhave large herds of Indian sambar and chital. The Indian sambar are more gregarious in Sri Lanka than other parts of their range and tend to form larger herds than elsewhere.  A coupleSambardoes and aChitalbuck roaming theSigur Plateauin southern India. The Chao Praya River Valley of Thailand was once primarily tropical seasonal moist deciduous forest and wet savanna that hosted populations of hog deer, the now-extinctSchomburgk's deer,Eld's deer, Indian sambar, and Indian muntjac. Both the hog deer and Eld's deer are rare, whereas Indian sambar and Indian muntjac thrive in protected national parks, such asKhao Yai. Many of these South Asian and Southeast Asian deer species also share their habitat with otherherbivores, such asAsian elephants, the various Asian rhinoceros species, various antelope species (such asnilgai,four-horned antelope,blackbuck, andIndian gazellein India), and wild oxen (such aswild Asian water buffalo,gaur,banteng, andkouprey). One way that different herbivores can survive together in a given area is for each species to have different food preferences, although there may be some overlap. As a result ofacclimatisation societyreleases in the 19th century, Australia has sixintroduced speciesof deer that have established sustainable wild populations. They are fallow deer, red deer, sambar, hog deer,rusa, and chital. Red deer were introduced into New Zealand in 1851 from English and Scottish stock. Many have been domesticated indeer farmssince the late 1960s and are common farm animals there now. Seven other species of deer were introduced into New Zealand but none are as widespread as red deer.[7] DescriptionEdit  Deer tails: White-tailed deer Mule deer Black-tailed deer Elk Red deer Deer constitute the second most diverse family of artiodactyla after bovids.[8]Though of a similar build, deer are strongly distinguished fromantelopesby theirantlers, which are temporary and regularly regrown unlike the permanenthornsof bovids.[9]Characteristics typical of deer include long, powerful legs, a diminutive tail and long ears.[10]Deer exhibit a broad variation in physical proportions. Thelargestextant deer is themoose, which is nearly 2.6 metres (8ft 6in) tall and weighs up to 800 kilograms (1,800lb).[11][12]The elk stands 1.4–2 metres (4ft 7in– 6ft 7in) at the shoulder and weighs 240–450 kilograms (530–990lb).[13]The northern pudu is the smallest deer in the world; it reaches merely32–35 centimetres (12+1⁄2–14in) at the shoulder and weighs3.3–6 kilograms (7+1⁄4–13+1⁄4lb). The southern pudu is only slightly taller and heavier.[14]Sexual dimorphismis quite pronounced – in most species males tend to be larger than females,[15]and, except for the reindeer, only males possess antlers.[16] Coat colour generally varies between red and brown,[17]though it can be as dark as chocolate brown in the tufted deer[18]or have a grayish tinge as in elk.[13]Different species of brocket deer vary from gray to reddish brown in coat colour.[19]Several species such as the chital,[20]the fallow deer[21]and the sika deer[22]feature white spots on a brown coat. Coat of reindeer shows notable geographical variation.[23]Deer undergo twomoultsin a year;[17][24]for instance, in red deer the red, thin-haired summer coat is gradually replaced by the dense, greyish brown winter coat in autumn, which in turn gives way to the summer coat in the following spring.[25]Moulting is affected by thephotoperiod.[26] Deer are also excellent jumpers and swimmers. Deer areruminants, or cud-chewers, and have a four-chambered stomach. Some deer, such as those on the island ofRùm,[27]do consume meat when it is available.[28] Nearly all deer have a facial gland in front of each eye. The gland contains a strongly scentedpheromone, used tomarkits home range. Bucks of a wide range of species open these glands wide when angry or excited. All deer have aliverwithout agallbladder. Deer also have atapetum lucidum, which gives them sufficiently goodnight vision. AntlersEdit Main article:Antler  White-tailed deer All male deer possessantlers, with the exception of thewater deer, in which males have long tusk-like canines that reach below the lower jaw.[29]Females generally lack antlers, though female reindeer bear antlers smaller and less branched than those of the males.[30]Occasionally females in other species may develop antlers, especially in telemetacarpal deer such as European roe deer, red deer, white-tailed deer and mule deer and less often in plesiometacarpal deer. A study of antlered female white-tailed deer noted that antlers tend to be small and malformed, and are shed frequently around the time of parturition.[31]  Antler phylogenetics The fallow deer and the various subspecies of the reindeer have the largest as well as the heaviest antlers, both in absolute terms as well as in proportion to body mass (an average of eight grams per kilogram of body mass);[30][32]the tufted deer, on the other hand, has the smallest antlers of all deer, while the pudú has the lightest antlers with respect to body mass (0.6g per kilogram of body mass).[30]The structure of antlers show considerable variation; while fallow deer and elk antlers are palmate (with a broad central portion), white-tailed deer antlers include a series of tines sprouting upward from a forward-curving main beam, and those of the pudú are mere spikes.[14]Antler development begins from the pedicel, a bony structure that appears on the top of the skull by the time the animal is a year old. The pedicel gives rise to a spiky antler the following year, that is replaced by a branched antler in the third year. This process of losing a set of antlers to develop a larger and more branched set continues for the rest of the life.[30]The antlers emerge as soft tissues (known asvelvet antlers) and progressively harden into bony structures (known as hard antlers), followingmineralisationand blockage ofblood vesselsin the tissue, from the tip to the base.[33]  TwoSambar deerfighting,Silvassa, India Antlers might be one of the most exaggerated malesecondary sexual characteristics,[34]and are intended primarily for reproductive success throughsexual selectionand for combat. The tines (forks) on the antlers create grooves that allow another male's antlers to lock into place. This allows the males to wrestle without risking injury to the face.[35]Antlers are correlated to an individual's position in the social hierarchy and its behaviour. For instance, the heavier the antlers, the higher the individual's status in the social hierarchy, and the greater the delay in shedding the antlers;[30]males with larger antlers tend to be more aggressive and dominant over others.[36]Antlers can be anhonest signalof genetic quality; males with larger antlers relative to body size tend to have increased resistance topathogens[37]and higher reproductive capacity.[38] In elk inYellowstone National Park, antlers also provide protection against predation bywolves.[39] Homology of tines, that is, the branching structure of antlers among species, have been discussed before the 1900s.[40][41][42]Recently, a new method to describe the branching structure of antlers and determining homology of tines was developed.[43] TeethEdit  An example of a deer's mandible and teeth Most deer bear 32 teeth; the correspondingdental formulais:0.0.3.33.1.3.3. The elk and the reindeer may be exceptions, as they may retain their upper canines and thus have 34 teeth (dental formula:0.1.3.33.1.3.3).[44]The Chinese water deer, tufted deer, andmuntjachave enlarged uppercanine teethforming sharp tusks, while other species often lack upper canines altogether. The cheek teeth of deer have crescent ridges of enamel, which enable them to grind a wide variety of vegetation.[45]The teeth of deer are adapted to feeding on vegetation, and like other ruminants, they lack upperincisors, instead having a tough pad at the front of their upper jaw. BiologyEdit  ARoe deerbrowsing tree leaves inBrastad, Sweden. DietEdit Deer arebrowsers, and feed primarily on foliage ofgrasses,sedges,forbs,shrubsandtrees, secondarily onlichensin northern latitudes during winter.[46]They have small, unspecialized stomachs byruminantstandards, and high nutrition requirements. Rather than eating and digesting vast quantities of low-grade fibrous food as, for example,sheepandcattledo, deer select easily digestible shoots, young leaves, fresh grasses, soft twigs, fruit,fungi, andlichens. The low-fibered food, after minimal fermentation and shredding, passes rapidly through the alimentary canal. The deer require a large amount of minerals such ascalciumand phosphate in order to support antler growth, and this further necessitates a nutrient-rich diet. There are some reports of deer engaging in carnivorous activity, such as eating deadalewivesalong lakeshores[47]or depredating the nests ofnorthern bobwhites.[48] ReproductionEdit Main article:Rut (mammalian reproduction) §Cervidae  Femaleelknursing young Nearly all cervids are so-calleduniparentalspecies: the fawns are only cared for by the mother, known as a doe. A doe generally has one or two fawns at a time (triplets, while not unknown, are uncommon). Mating season typically begins in later August and lasts until December. Some species mate until early March. Thegestation periodis anywhere up to ten months for the European roe deer. Most fawns are born with their fur covered with white spots, though in many species they lose these spots by the end of their first winter. In the first twenty minutes of a fawn's life, the fawn begins to take its first steps. Its mother licks it clean until it is almost free of scent, sopredatorswill not find it. Its mother leaves often to graze, and the fawn does not like to be left behind. Sometimes its mother must gently push it down with her foot.[49][bettersourceneeded]The fawn stays hidden in the grass for one week until it is strong enough to walk with its mother. The fawn and its mother stay together for about one year. A male usually leaves and never sees his mother again, but females sometimes come back with their own fawns and form small herds. DiseaseEdit In some areas of the UK, deer (especiallyfallow deerdue to theirgregarious behaviour) have been implicated as a possible reservoir for transmission ofbovine tuberculosis,[50][51]a disease which in the UK in 2005 cost £90million in attempts to eradicate.[52]In New Zealand, deer are thought to be important as vectors picking upM. bovisin areas where brushtail possumsTrichosurus vulpeculaare infected, and transferring it to previously uninfected possums when their carcasses are scavenged elsewhere.[53]The white-tailed deerOdocoileus virginianushas been confirmed as the sole maintenance host in the Michigan outbreak of bovine tuberculosis which remains a significant barrier to the US nationwide eradication of the disease in livestock.[54]Moose and deer can carryrabies.[55] Docile moose may suffer frombrain worm, ahelminthwhich drills holes through the brain in its search for a suitable place to lay its eggs. A government biologist states that "They move around looking for the right spot and never really find it." Deer appear to be immune to this parasite; it passes through the digestive system and is excreted in the feces. The parasite is not screened by the moose intestine, and passes into the brain where damage is done that is externally apparent, both in behaviour and in gait.[55] Deer, elk and moose in North America may suffer fromchronic wasting disease, which was identified at aColoradolaboratory in the 1960s and is believed to be a prion disease. Out of an abundance of caution hunters are advised to avoid contact withspecified risk material(SRM) such as the brain, spinal column or lymph nodes. Deboning the meat when butchering and sanitizing the knives and other tools used to butcher are amongst other government recommendations.[56] EvolutionEdit Deer are believed to have evolved from antlerless,tuskedancestors that resembled modernduikersand diminutive deer in the earlyEocene, and gradually developed into the first antlered cervoids (thesuperfamilyof cervids and related extinct families) in theMiocene. Eventually, with the development of antlers, the tusks as well as the upperincisorsdisappeared. Thus, evolution of deer took nearly 30 million years. BiologistValerius Geistsuggests evolution to have occurred in stages. There are not many prominent fossils to trace this evolution, but only fragments of skeletons and antlers that might be easily confused with false antlers of non-cervid species.[14][57] EoceneEdit Theruminants, ancestors of the Cervidae, are believed to have evolved fromDiacodexis, the earliest known artiodactyl (even-toed ungulate), 50–55 Mya in the Eocene.[58]Diacodexis, nearly the size of arabbit, featured thetalus bonecharacteristic of all moderneven-toed ungulates. This ancestor and its relatives occurred throughout North America and Eurasia, but were on the decline by at least 46 Mya.[58][59]Analysis of a nearly complete skeleton ofDiacodexisdiscovered in 1982 gave rise to speculation that this ancestor could be closer to the non-ruminants than the ruminants.[60]Andromeryxis another prominent prehistoric ruminant, but appears to be closer to thetragulids.[61] OligoceneEdit  Leptomeryx The formation of theHimalayasand theAlpsbrought about significant geographic changes. This was the chief reason behind the extensive diversification of deer-like forms and the emergence of cervids from theOligoceneto the earlyPliocene.[62]The latter half of the Oligocene (28–34 Mya) saw the appearance of the EuropeanEumeryxand the North AmericanLeptomeryx. The latter resembled modern-day bovids and cervids in dental morphology (for instance, it hadbrachyodontmolars), while the former was moreadvanced.[63]Other deer-like forms included the North AmericanBlastomeryxand the EuropeanDremotherium; these sabre-toothed animals are believed to have been the direct ancestors of all modern antlered deer, though they themselves lacked antlers.[64]Another contemporaneous form was the four-hornedprotoceratidProtoceras, that was replaced bySyndyocerasin the Miocene; these animals were unique in having a horn on the nose.[57]Late Eocene fossils dated approximately 35 million years ago, which were found in North America, show thatSyndyocerashad bony skull outgrowths that resembled non-deciduous antlers.[65] MioceneEdit Fossil evidence suggests that the earliest members of the superfamily Cervoidea appeared in Eurasia in the Miocene.Dicrocerus,EuproxandHeteroproxwere probably the first antlered cervids.[66]Dicrocerusfeatured single-forked antlers that were shed regularly.[67]Stephanocemashad more developed and diffuse ("crowned") antlers.[68]Procervulus(Palaeomerycidae) also possessed antlers that were not shed.[69]Contemporary forms such as themerycodontineseventually gave rise to the modern pronghorn.[70] The Cervinae emerged as the first group of extant cervids around 7–9 Mya, during the late Miocene in central Asia. The tribe Muntiacini made its appearance as†Muntiacus leilaoensisaround 7–8 Mya;[71]The early muntjacs varied in size–as small as hares or as large as fallow deer. They had tusks for fighting and antlers for defence.[14]Capreolinae followed soon after; Alceini appeared 6.4–8.4 Mya.[72]Around this period, theTethys Oceandisappeared to give way to vast stretches of grassland; these provided the deer with abundant protein-rich vegetation that led to the development of ornamental antlers and allowed populations to flourish and colonise areas.[14][62]As antlers had become pronounced, the canines were either lost or became poorly represented (as in elk), probably because diet was no longerbrowse-dominated and antlers were better display organs. In muntjac and tufted deer, the antlers as well as the canines are small. The tragulids possess long canines to this day.[59] PlioceneEdit  Cervocerus novorossiae With the onset of thePliocene, the global climate became cooler. A fall in the sea-level led to massive glaciation; consequently, grasslands abounded in nutritious forage. Thus a new spurt in deer populations ensued.[14][62]The oldest member of Cervini,†Cervocerus novorossiae, appeared around the transition from Miocene to Pliocene (4.2–6 Mya) in Eurasia;[73]cervine fossils from early Pliocene to as late as thePleistocenehave been excavated in China[74]and the Himalayas.[75]WhileCervusandDamaappeared nearly 3 Mya,Axisemerged during the late Pliocene–Pleistocene. The tribes Capreolini and Rangiferini appeared around 4–7 Mya.[72] Around 5 Mya, the rangiferina†Bretziaand†Eocoileuswere the first cervids to reach North America.[72]This implies the Bering Strait could be crossed during the late Miocene–Pliocene; this appears highly probable as thecamelidsmigrated into Asia from North America around the same time.[76]Deer invaded South America in the late Pliocene (2.5–3 Mya) as part of theGreat American Interchange, thanks to the recently formedIsthmus of Panama, and emerged successful due to the small number of competing ruminants in the continent.[77] PleistoceneEdit Large deer with impressive antlers evolved during the early Pleistocene, probably as a result of abundant resources to drive evolution.[14]The early Pleistocene cervid†Eucladoceroswas comparable in size to the modern elk.[78]†Megaloceros(Pliocene–Pleistocene) featured theIrish elk(M. giganteus), one of thelargest known cervids. The Irish elk reached2 metres (6+1⁄2ft) at the shoulder and had heavy antlers that spanned 3.6 metres (11ft 10in) from tip to tip.[79]These large animals are thought to have faced extinction due to conflict betweensexual selectionfor large antlers and body andnatural selectionfor a smaller form.[80]Meanwhile, the moose and reindeer radiated into North America from Siberia.[81] Taxonomy and classificationEdit  Cervid skull Further information:List of cervids Deer constitute theartiodactylfamilyCervidae. This family was firstdescribedby German zoologistGeorg August GoldfussinHandbuch der Zoologie(1820). Threesubfamiliesare recognised: Capreolinae (first described by the English zoologistJoshua Brookesin 1828), Cervinae (described by Goldfuss) and Hydropotinae (first described by French zoologistÉdouard Louis Trouessartin 1898).[8][82] Other attempts at the classification of deer have been based on morphological andgeneticdifferences.[57]The Anglo-Irish naturalistVictor Brookesuggested in 1878 that deer could be bifurcated into two classes on the according to the features of the second and fifthmetacarpal bonesof their forelimbs: Plesiometacarpalia (most Old World deer) and Telemetacarpalia (most New World deer). He treated themusk deeras a cervid, placing it under Telemetacarpalia. While the telemetacarpal deer showed only those elements located far from the joint, the plesiometacarpal deer retained the elements closer to the joint as well.[83]Differentiation on the basis ofdiploidnumber ofchromosomesin the late 20th century has been flawed by several inconsistencies.[57] In 1987, the zoologistsColin GrovesandPeter Grubbidentified three subfamilies: Cervinae, Hydropotinae and Odocoileinae; they noted that the hydropotines lack antlers, and the other two subfamilies differ in their skeletal morphology.[84]They reverted from this classification in 2000.[85] Molecular phylogenetic analyses since the latter half of the 2000s all show thathydropotesis a sister taxon ofCapreolus, and “Hydropotinae” became outdated subfamily.[86][87][88][89][90] External relationshipsEdit Until 2003, it was understood that the familyMoschidae(musk deer) wassisterto Cervidae. Then aphylogeneticstudy by Alexandre Hassanin (ofNational Museum of Natural History, France) and colleagues, based onmitochondrialandnuclearanalyses, revealed that Moschidae andBovidaeform acladesister to Cervidae. According to the study, Cervidaedivergedfrom the Bovidae-Moschidae clade 27 to 28 million years ago.[91]The followingcladogramis based on the 2003 study.[91] RuminantiaTragulina Tragulidae  Pecora  Antilocapridae    Giraffidae     Cervidae     Bovidae    Moschidae       Internal relationshipsEdit A 2006phylogeneticstudy of the internal relationships in Cervidae by Clément Gilbert and colleagues divided the family into two major clades: Capreolinae (telemetacarpal or New World deer) and Cervinae (plesiometacarpal or Old World deer). Studies in the late 20th century suggested a similar bifurcation in the family. This as well as previous studies supportmonophylyin Cervinae, while Capreolinae appearsparaphyletic. The 2006 study identified two lineages in Cervinae, Cervini (comprising the generaAxis,Cervus,DamaandRucervus) and Muntiacini (MuntiacusandElaphodus). Capreolinae featured three lineages, Alceini (Alcesspecies), Capreolini (Capreolusand the subfamily Hydropotinae) and Rangiferini (Blastocerus,Hippocamelus,Mazama,Odocoileus,PuduandRangiferspecies). The following cladogram is based on the 2006 study.[72] CervidaeCervinae(OldWorlddeer)Muntiacini  Reeves's muntjac    Tufted deer   Cervini    Common fallow deer    Persian fallow deer        Rusa    Sambar      Red deer    Thorold's deer    Sika deer    Elk(Wapiti)       Eld's deer    Père David's deer        Barasingha     Indian hog deer    Chital      Capreolinae(NewWorlddeer)Rangiferini  Reindeer(Caribou)      American red brocket     White-tailed deer    Mule deer       Marsh deer    Gray brocket    Southern pudu    Taruca     Capreolini  Roe deer    Water deer   Alceini MooseorEurasian elk     Human interactionEdit  Upper Palaeolithiccave paintingof aMegalocerosgiant deer atLascaux, 17,300 years old Further information:Deer in mythology PrehistoricEdit Deer were an important source of food for early hominids. In China,Homo erectusfed upon thesika deer, while the red deer was hunted in Germany. In theUpper Palaeolithic, the reindeer was the staple food forCro-Magnonpeople,[92]while thecave paintingsatLascauxin southwestern France include some 90 images of stags.[93]InChina, deer continued to be a main source of food for millennia even after people began farming, and it is possible that sika and other deer benefited from the frequently abandoned field sites.[94] HistoricEdit  Ancient Greekgilt-silverrhyton, 4th century BC Deer had a central role in the ancient art, culture and mythology of theHittites, theancient Egyptians, theCelts, theancient Greeks, the Asians and several others. For instance, theStag Hunt Mosaicof ancientPella, under theKingdom of Macedonia(4th century BC), possibly depictsAlexander the Greathunting a deer withHephaestion.[95]In JapaneseShintoism, the sika deer is believed to be a messenger to the gods.In China, deer are associated with great medicinal significance;deer penisis thought by some in China to haveaphrodisiacproperties.[96]Spotted deer are believed in China to accompany the god of longevity. Deer was the principal sacrificial animal for the Huichal Indians of Mexico. In medieval Europe, deer appeared in hunting scenes and coats-of-arms. Deer are depicted in many materials by various pre-Hispanic civilizations in the Andes.[92][97] The common male first nameOscaris taken from theIrish Language, where it is derived from two elements: the first,os, means "deer"; the second element,cara, means "friend". The name is borne by a famous hero ofIrish mythology—Oscar, grandson ofFionn Mac Cumhail. The name was popularised in the 18th century byJames Macpherson, creator of 'Ossianic poetry'. LiteraryEdit  In the Indian epicRamayana,Ramakills the illusionalgolden deer. Deer have been an integral part of fables and other literary works since the inception of writing. Stags were used as symbols in the latter Sumerian writings. For instance, the boat of Sumerian god Enki is named theStag of Azbu. There are several mentions of the animal in theRigvedaas well as theBible. In the Indian epicRamayana,Sitais lured by a golden deer whichRamatries to catch. In the absence of both Rama andLakshman,Ravanakidnaps Sita. Many of the allegoricalAesop's fables, such as "The Stag at the Pool", "The One-Eyed Doe" and "The Stag and a Lion", personify deer to give moral lessons. For instance, "The Sick Stag" gives the message that uncaring friends can do more harm than good.[92]TheYaquideer song accompanies the deer dance which is performed by a pascola [from the Spanish 'pascua', Easter] dancer (also known as a deer dancer). Pascolas would perform at religious and social functions many times of the year, especially during Lent and Easter.[92][98] In one ofRudolf Erich Raspe's 1785 stories ofBaron Munchausen's Narrative of his Marvellous Travels and Campaigns in Russia, the baron encounters a stag while eating cherries and, without ammunition, fires the cherry-pits at the stag with his musket, but it escapes. The next year, the baron encounters a stag with acherry treegrowing from its head; presumably this is the animal he had shot at the previous year. InChristmaslore (such as in the narrative poem "A Visit from St. Nicholas"),reindeerare often depicted pulling thesleighofSanta Claus.[99]Marjorie Kinnan Rawlings'sPulitzer Prize-winning 1938 novelThe Yearlingwas about a boy's relationship with a baby deer. The fiction bookFire Bringeris about a young fawn who goes on a quest to save the Herla, the deer kind.[100]In the 1942Walt Disney Picturesfilm,Bambiis awhite-tailed deer, while inFelix Salten's original 1923 bookBambi, a Life in the Woods, he is aroe deer. InC. S. Lewis's 1950 fantasy novelThe Lion, the Witch and the Wardrobethe adult Pevensies, now kings and queens ofNarnia, chase the White Stag on a hunt, as the Stag is said to grant its captor a wish. The hunt is key in returning the Pevensies to their home in England. In the 1979 bookThe Animals of Farthing Wood, The Great White Stag is the leader of all the animals. HeraldicEdit  Arms ofRaon-aux-Bois, France  Arms ofÅland Deer of various types appear frequently in Europeanheraldry. In the British armory, the term "stag" is typically used to refer to antlered male red deer, while "buck" indicates an antlered male fallow deer. Stags and bucks appear in a number ofattitudes, referred to as "lodged" when the deer is lying down, "trippant" when it has one leg raised, "courant" when it is running, "springing" when in the act of leaping, "statant" when it is standing with all hooves on the ground and looking ahead, and "at gaze" when otherwise statant but looking at the viewer. Stags' heads are also frequently used; these are typically portrayed without an attached neck and as facing the viewer, in which case they are termed "caboshed".[101] Examples of deer incoats of armscan be found in the arms ofHertfordshire, England, and its county town ofHertford; both are examples ofcanting arms. A deer appears on the arms of theIsraeli Postal Authority. Coats of arms featuring deer include those ofDotternhausen,Thierachern,Friolzheim,Bauen,Albstadt, andDasselin Germany; of theEarls Bathurstin England;[102]ofBalakhna, Russia; ofÅland, Finland; ofGjemnes,Hitra,Hjartdal,RendalenandVossin Norway; ofJelenia Góra, Poland; ofUmeå, Sweden; ofQueensland, Australia; ofCervera, Catalonia; of Northern Ireland; and of Chile.[citation needed] Other types of deer used in heraldry include the hind, portrayed much like the stag or buck but without antlers, as well as the reindeer and winged stags. Winged stags are used assupportersin the arms of thede Carteret family. The sea-stag, possessing the antlers, head, forelegs and upper body of a stag and the tail of amermaid, is often found in German heraldry.[101] EconomicEdit  Bronze deer,Warring States period Deer have long had economic significance to humans. Deer meat, known asvenison, is highly nutritious.[103][104]Due to the inherently wild nature and diet of deer, venison is most often obtained through deer hunting. In the United States, it is produced in small amounts compared tobeef, but still represents a significant trade. Deer hunting is a popular activity in the U.S. that can provide the hunter's family with high quality meat and generates revenue for states and the federal government from the sales of licenses, permits and tags. The 2006 survey by theU.S. Fish and Wildlife Serviceestimates that license sales generate approximately $700 million annually. This revenue generally goes to support conservation efforts in the states where the licenses are purchased. Overall, the U.S. Fish and Wildlife Service estimates that big game hunting for deer and elk generates approximately $11.8 billion annually in hunting-related travel, equipment and related expenditures.[105]Conservation laws prevent the sale of unlicensed wild game meat, although it may be donated.  Nicholas Mavrogenes,PhanariotePrinceofWallachia, riding throughBucharestin a stag−drawn carriage. Late 1780s Deer have often been bred in captivity as ornaments for parks, but only in the case of reindeer has thorough domestication succeeded.[106]By 2012, some 25,000 tons of red deer were raised on farms in North America. TheSamiof Scandinavia and theKola Peninsulaof Russia and other nomadic peoples of northern Asia use reindeer for food, clothing, and transport. Others are bred for hunting are selected based on the size of the antlers.[107]The major deer-producing countries are New Zealand, the market leader, with Ireland, Great Britain and Germany. The trade earns over $100 million annually for these countries.[108] Automobile collisions with deer can impose a significant cost on the economy. In the U.S., about 1.5million deer-vehicle collisions occur each year, according to theNational Highway Traffic Safety Administration. Those accidents cause about 150 human deaths and $1.1billion in property damage annually.[109]In Scotland, several roads including theA82, theA87and theA835have had significant enough problems withdeer vehicle collisions(DVCs) that sets of vehicle activated automatic warning signs have been installed along these roads.[110]  Leather side of aRoe deerhide The skins make a peculiarly strong, soft leather, known asbuckskin. There is nothing special about skins with the fur still on since the hair is brittle and soon falls off. The hoofs and horns are used for ornamental purposes, especially the antlers of theroe deer, which are utilized for making umbrella handles, and for similar purposes; elk horn is often employed in making knife handles. Among theInuit, the traditionaluluwomen's knife was made with an antler, horn, or ivory handle.[111]In China, a medicine is made from stag horn, and the antlers of certain species are eaten when "in the velvet".[106]Velvet antlers in medicine have been shown to have health benefits including an enhanced immune system and athletic performance, as well as being effective treatment for arthritis. Antlers can also be boiled down to release the protein gelatin, which is used as a topical treatment for skin irritation and is also used in cooking.[112] Since the early 20th century, deer have become commonly thought of as pests in New Zealand due to a lack of predators on the island causing population numbers to increase and begin encroaching on more populated areas. They compete with livestock for resources, as well as cause excess erosion and wreak havoc on wild plant species and agriculture alike. They can also have an effect on the conservation efforts of other plant and animal species, as they can critically offset the balance within an environment by drastically depleting diversity within forests.[113]

Thegoatordomestic goat(Capra hircus) is adomesticatedspecies ofgoat-antelopetypically kept aslivestock. It wasdomesticatedfrom thewild goat(C. aegagrus) ofSouthwest AsiaandEastern Europe. The goat is a member of the animal familyBovidaeand the tribeCaprini, meaning it is closely related to thesheep. There are over 300 distinctbreedsof goat.[1]It is one of the oldest domesticated species of animal, according to archaeological evidence that its earliest domestication occurred in Iran at 10,000 calibrated calendar years ago. Domestic goat Temporal range:0.01–0Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓ Neolithic–Recent Apygmy goaton atree stump Conservation status Domesticated Scientific classificationKingdom:AnimaliaPhylum:ChordataClass:MammaliaOrder:ArtiodactylaFamily:BovidaeSubfamily:CaprinaeTribe:CapriniGenus:CapraSpecies: C.hircus Binomial nameCapra hircus Linnaeus,1758 Synonyms Capra aegagrus hircusLinnaeus,1758 Capra depressaLinnaeus,1758 Capra mambricaLinnaeus,1758 Capra reversaLinnaeus,1758 Goat-herding is an ancient tradition that is still important in places such as Egypt. Goats have been used formilk,meat,fur, andskinsacross much of the world.[3]Milk from goats is often turned intogoat cheese. Female goats are referred to asdoesornannies,intactmales are calledbucksorbillies, and juvenile goats of both sexes are calledkids.Castratedmales are calledwethers. While the wordshircineandcaprineboth refer to anything having a goat-like quality,hircineis used most often to emphasize the distinct smell of domestic goats. In 2011, there were more than 924 million goats living in the world, according to theUNFood and Agriculture Organization.

Deerortrue deerarehoofedruminantmammalsforming thefamilyCervidae. The two main groups of deer are theCervinae, including themuntjac, theelk(wapiti), thered deer, and thefallow deer; and theCapreolinae, including thereindeer(caribou),white-tailed deer, theroe deer, and themoose. Male deer of all species (except thewater deer) as well as female reindeer, grow and shed newantlerseach year. In this they differ from permanentlyhornedantelope, which are part of a different family (Bovidae) within the same order ofeven-toed ungulates(Artiodactyla). Deer[1] Temporal range:Early Oligocene–Recent PreꞒ Ꞓ O S D C P T J K Pg N Images of a few members of the family Cervidae (counterclockwise from top left): theelk(Cervus canadensis),white-tailed deer(Odocoileus virginianus),grey brocket(Mazama gouazoubira),barasingha(Rucervus duvaucelii),pudú(Genus:Pudu),sika deer(Cervus nippon),red deer(Cervus elaphus), andreindeer(Rangifer tarandus)Scientific classificationKingdom:AnimaliaPhylum:ChordataClass:MammaliaOrder:ArtiodactylaInfraorder:PecoraFamily:Cervidae Goldfuss, 1820Type genusCervus Linnaeus, 1758 Subfamilies Capreolinae Cervinae Combined native range of all species of deer. Themusk deer(Moschidae) of Asia andchevrotains(Tragulidae) of tropical African and Asian forests are separate families that are also in the ruminant cladeRuminantia; they are not especially closely related to Cervidae. Deer appear in art fromPaleolithiccave paintingsonwards, and they haveplayed a role in mythology, religion, and literature throughout history, as well as inheraldry, such as red deer that appear in thecoat of arms of Åland.[2]Their economic importance includes the use of their meat asvenison, their skins as soft, strongbuckskin, and their antlers as handles for knives. Deerhuntinghas been a popular activity since the Middle Ages and remains a resource for many families today. Contents Etymology and terminologyEdit  "The Stag Hunt ofFrederick III, Elector of Saxony" byLucas Cranach the Elder, 1529 The worddeerwas originally broad in meaning, becoming more specific with time.Old EnglishdēorandMiddle Englishdermeant a wild animal of any kind. Cognates of Old Englishdēorin other deadGermanic languageshave the general sense ofanimal, such asOld High Germantior,Old Norsedjurordȳr,Gothicdius,Old Saxondier, andOld Frisiandiar.[3]This general sense gave way to the modern English sense by the end of the Middle English period, around 1500. All modern Germanic languages save English and Scots retain the more general sense: for example, GermanTierand Norwegiandyrmeananimal.[4] For many types of deer in modern English usage, the male is abuckand the female adoe, but the terms vary with dialect, and according to the size of the species. The malered deeris astag, while for other large species the male is abull, the female acow, as in cattle. In older usage, the male of any species is ahart, especially if over five years old, and the female is ahind, especially if three or more years old.[5]The young of small species is afawnand of large species acalf; a very small young may be akid. A castrated male is ahavier.[6]A group of any species is aherd. Theadjectiveof relation iscervine; like the family nameCervidae, this is fromLatin:cervus, meaningstagordeer. DistributionEdit  Chitaldeer inNagarahole, India Deer live in a variety ofbiomes, ranging fromtundrato thetropical rainforest. While often associated with forests, many deer areecotonespecies that live in transitional areas between forests and thickets (for cover) and prairie and savanna (open space). The majority of large deer species inhabit temperate mixed deciduous forest, mountain mixed coniferous forest, tropical seasonal/dry forest, and savanna habitats around the world. Clearing open areas within forests to some extent may actually benefit deer populations by exposing theunderstoryand allowing the types of grasses, weeds, and herbs to grow that deer like to eat. Access to adjacent croplands may also benefit deer. Adequate forest or brush cover must still be provided for populations to grow and thrive. Deer are widely distributed, with indigenous representatives in all continents exceptAntarcticaandAustralia, thoughAfricahas only one native deer, theBarbary stag, a subspecies ofred deerthat is confined to theAtlas Mountainsin the northwest of the continent. Another extinct species of deer,Megaceroides algericus,was present inNorth Africauntil 6000 years ago.Fallow deerhave been introduced toSouth Africa. Small species ofbrocket deerandpudúsofCentralandSouth America, andmuntjacsofAsiagenerally occupy dense forests and are less often seen in open spaces, with the possible exception of theIndian muntjac. There are also several species of deer that are highly specialized and live almost exclusively in mountains, grasslands, swamps, and "wet" savannas, orriparian corridorssurrounded bydeserts. Some deer have a circumpolar distribution in bothNorth AmericaandEurasia. Examples include thecaribouthat live in Arctictundraandtaiga(boreal forests) andmoosethat inhabit taiga and adjacent areas. Huemul deer (tarucaandChilean huemul) ofSouth America'sAndesfill the ecological niches of theibexandwild goat, with the fawns behaving more likegoatkids. The highest concentration of large deer species in temperate North America lies in theCanadian Rocky MountainandColumbia Mountainregions between Alberta and British Columbia where all five North American deer species (white-tailed deer,mule deer,caribou,elk, andmoose) can be found. This region has several clusters of national parks includingMount Revelstoke National Park,Glacier National Park (Canada),Yoho National Park, andKootenay National Parkon the British Columbia side, andBanff National Park,Jasper National Park, andGlacier National Park (U.S.)on the Alberta and Montana sides. Mountain slope habitats vary from moist coniferous/mixed forested habitats to dry subalpine/pine forests with alpine meadows higher up. The foothills and river valleys between the mountain ranges provide a mosaic of cropland and deciduous parklands. The rare woodland caribou have the most restricted range living at higher altitudes in the subalpine meadows andalpine tundraareas of some of the mountain ranges. Elk and mule deer both migrate between the alpine meadows and lower coniferous forests and tend to be most common in this region. Elk also inhabit river valley bottomlands, which they share with White-tailed deer. The White-tailed deer have recently expanded their range within the foothills and river valley bottoms of the Canadian Rockies owing to conversion of land to cropland and the clearing of coniferous forests allowing more deciduous vegetation to grow up the mountain slopes. They also live in the aspen parklands north of Calgary and Edmonton, where they share habitat with the moose. The adjacentGreat Plainsgrassland habitats are left to herds of elk,American bison, andpronghorn.  Reindeerherds standing on snow to avoid flies TheEurasianContinent (including the Indian Subcontinent) boasts the most species of deer in the world, with most species being found in Asia. Europe, in comparison, has lower diversity in plant and animal species. Many national parks and protected reserves in Europe have populations of red deer,roe deer, and fallow deer. These species have long been associated with the continent of Europe, but also inhabitAsia Minor, theCaucasus Mountains, and NorthwesternIran. "European" fallow deer historically lived over much of Europe during the Ice Ages, but afterwards became restricted primarily to the Anatolian Peninsula, in present-day Turkey. Present-day fallow deer populations in Europe are a result of historic man-made introductions of this species, first to the Mediterranean regions of Europe, then eventually to the rest of Europe. They were initially park animals that later escaped and reestablished themselves in the wild. Historically, Europe's deer species shared their deciduous forest habitat with other herbivores, such as the extincttarpan(forest horse), extinctaurochs(forest ox), and the endangeredwisent(European bison). Good places to see deer in Europe include theScottish Highlands, theAustrianAlps, thewetlandsbetweenAustria,Hungary, and theCzech Republic, and some National Parks, includingDoñana National ParkinSpain, theVeluwein theNetherlands, theArdennesinBelgium, andBiałowieża National ParkinPoland.Spain,Eastern Europe, and theCaucasus Mountainshave forest areas that are not only home to sizable deer populations but also other animals that were once abundant such as the wisent,Eurasian lynx,Iberian lynx,wolves, andbrown bears.  Somesika deer(Cervus nippon) andJapanese macaques(Macaca fuscata) along a waterside The highest concentration of large deer species in temperate Asia occurs in the mixed deciduous forests, mountain coniferous forests, and taiga bordering North Korea, Manchuria (Northeastern China), and the Ussuri Region (Russia). These are among some of the richest deciduous and coniferous forests in the world where one can findSiberian roe deer,sika deer, elk, and moose. Asian caribou occupy the northern fringes of this region along the Sino-Russian border. Deer such as the sika deer,Thorold's deer,Central Asian red deer, and elk have historically been farmed for their antlers byHan Chinese,Turkic peoples,Tungusic peoples,Mongolians, andKoreans. Like theSami peopleof Finland and Scandinavia, the Tungusic peoples, Mongolians, and Turkic peoples of Southern Siberia, Northern Mongolia, and the Ussuri Region have also taken to raising semi-domesticated herds of Asian caribou. The highest concentration of large deer species in the tropics occurs in Southern Asia in India's Indo-Gangetic Plain Region andNepal's Terai Region. These fertile plains consist of tropical seasonal moist deciduous, dry deciduous forests, and both dry and wet savannas that are home tochital,hog deer,barasingha, Indiansambar, andIndian muntjac. Grazing species such as the endangered barasingha and very common chital are gregarious and live in large herds. Indian sambar can be gregarious but are usually solitary or live in smaller herds. Hog deer are solitary and have lower densities than Indian muntjac. Deer can be seen in several national parks in India, Nepal, and Sri Lanka of whichKanha National Park,Dudhwa National Park, andChitwan National Parkare most famous. Sri Lanka'sWilpattu National ParkandYala National Parkhave large herds of Indian sambar and chital. The Indian sambar are more gregarious in Sri Lanka than other parts of their range and tend to form larger herds than elsewhere.  A coupleSambardoes and aChitalbuck roaming theSigur Plateauin southern India. The Chao Praya River Valley of Thailand was once primarily tropical seasonal moist deciduous forest and wet savanna that hosted populations of hog deer, the now-extinctSchomburgk's deer,Eld's deer, Indian sambar, and Indian muntjac. Both the hog deer and Eld's deer are rare, whereas Indian sambar and Indian muntjac thrive in protected national parks, such asKhao Yai. Many of these South Asian and Southeast Asian deer species also share their habitat with otherherbivores, such asAsian elephants, the various Asian rhinoceros species, various antelope species (such asnilgai,four-horned antelope,blackbuck, andIndian gazellein India), and wild oxen (such aswild Asian water buffalo,gaur,banteng, andkouprey). One way that different herbivores can survive together in a given area is for each species to have different food preferences, although there may be some overlap. As a result ofacclimatisation societyreleases in the 19th century, Australia has sixintroduced speciesof deer that have established sustainable wild populations. They are fallow deer, red deer, sambar, hog deer,rusa, and chital. Red deer were introduced into New Zealand in 1851 from English and Scottish stock. Many have been domesticated indeer farmssince the late 1960s and are common farm animals there now. Seven other species of deer were introduced into New Zealand but none are as widespread as red deer.[7] DescriptionEdit  Deer tails: White-tailed deer Mule deer Black-tailed deer Elk Red deer Deer constitute the second most diverse family of artiodactyla after bovids.[8]Though of a similar build, deer are strongly distinguished fromantelopesby theirantlers, which are temporary and regularly regrown unlike the permanenthornsof bovids.[9]Characteristics typical of deer include long, powerful legs, a diminutive tail and long ears.[10]Deer exhibit a broad variation in physical proportions. Thelargestextant deer is themoose, which is nearly 2.6 metres (8ft 6in) tall and weighs up to 800 kilograms (1,800lb).[11][12]The elk stands 1.4–2 metres (4ft 7in– 6ft 7in) at the shoulder and weighs 240–450 kilograms (530–990lb).[13]The northern pudu is the smallest deer in the world; it reaches merely32–35 centimetres (12+1⁄2–14in) at the shoulder and weighs3.3–6 kilograms (7+1⁄4–13+1⁄4lb). The southern pudu is only slightly taller and heavier.[14]Sexual dimorphismis quite pronounced – in most species males tend to be larger than females,[15]and, except for the reindeer, only males possess antlers.[16] Coat colour generally varies between red and brown,[17]though it can be as dark as chocolate brown in the tufted deer[18]or have a grayish tinge as in elk.[13]Different species of brocket deer vary from gray to reddish brown in coat colour.[19]Several species such as the chital,[20]the fallow deer[21]and the sika deer[22]feature white spots on a brown coat. Coat of reindeer shows notable geographical variation.[23]Deer undergo twomoultsin a year;[17][24]for instance, in red deer the red, thin-haired summer coat is gradually replaced by the dense, greyish brown winter coat in autumn, which in turn gives way to the summer coat in the following spring.[25]Moulting is affected by thephotoperiod.[26] Deer are also excellent jumpers and swimmers. Deer areruminants, or cud-chewers, and have a four-chambered stomach. Some deer, such as those on the island ofRùm,[27]do consume meat when it is available.[28] Nearly all deer have a facial gland in front of each eye. The gland contains a strongly scentedpheromone, used tomarkits home range. Bucks of a wide range of species open these glands wide when angry or excited. All deer have aliverwithout agallbladder. Deer also have atapetum lucidum, which gives them sufficiently goodnight vision. AntlersEdit Main article:Antler  White-tailed deer All male deer possessantlers, with the exception of thewater deer, in which males have long tusk-like canines that reach below the lower jaw.[29]Females generally lack antlers, though female reindeer bear antlers smaller and less branched than those of the males.[30]Occasionally females in other species may develop antlers, especially in telemetacarpal deer such as European roe deer, red deer, white-tailed deer and mule deer and less often in plesiometacarpal deer. A study of antlered female white-tailed deer noted that antlers tend to be small and malformed, and are shed frequently around the time of parturition.[31]  Antler phylogenetics The fallow deer and the various subspecies of the reindeer have the largest as well as the heaviest antlers, both in absolute terms as well as in proportion to body mass (an average of eight grams per kilogram of body mass);[30][32]the tufted deer, on the other hand, has the smallest antlers of all deer, while the pudú has the lightest antlers with respect to body mass (0.6g per kilogram of body mass).[30]The structure of antlers show considerable variation; while fallow deer and elk antlers are palmate (with a broad central portion), white-tailed deer antlers include a series of tines sprouting upward from a forward-curving main beam, and those of the pudú are mere spikes.[14]Antler development begins from the pedicel, a bony structure that appears on the top of the skull by the time the animal is a year old. The pedicel gives rise to a spiky antler the following year, that is replaced by a branched antler in the third year. This process of losing a set of antlers to develop a larger and more branched set continues for the rest of the life.[30]The antlers emerge as soft tissues (known asvelvet antlers) and progressively harden into bony structures (known as hard antlers), followingmineralisationand blockage ofblood vesselsin the tissue, from the tip to the base.[33]  TwoSambar deerfighting,Silvassa, India Antlers might be one of the most exaggerated malesecondary sexual characteristics,[34]and are intended primarily for reproductive success throughsexual selectionand for combat. The tines (forks) on the antlers create grooves that allow another male's antlers to lock into place. This allows the males to wrestle without risking injury to the face.[35]Antlers are correlated to an individual's position in the social hierarchy and its behaviour. For instance, the heavier the antlers, the higher the individual's status in the social hierarchy, and the greater the delay in shedding the antlers;[30]males with larger antlers tend to be more aggressive and dominant over others.[36]Antlers can be anhonest signalof genetic quality; males with larger antlers relative to body size tend to have increased resistance topathogens[37]and higher reproductive capacity.[38] In elk inYellowstone National Park, antlers also provide protection against predation bywolves.[39] Homology of tines, that is, the branching structure of antlers among species, have been discussed before the 1900s.[40][41][42]Recently, a new method to describe the branching structure of antlers and determining homology of tines was developed.[43] TeethEdit  An example of a deer's mandible and teeth Most deer bear 32 teeth; the correspondingdental formulais:0.0.3.33.1.3.3. The elk and the reindeer may be exceptions, as they may retain their upper canines and thus have 34 teeth (dental formula:0.1.3.33.1.3.3).[44]The Chinese water deer, tufted deer, andmuntjachave enlarged uppercanine teethforming sharp tusks, while other species often lack upper canines altogether. The cheek teeth of deer have crescent ridges of enamel, which enable them to grind a wide variety of vegetation.[45]The teeth of deer are adapted to feeding on vegetation, and like other ruminants, they lack upperincisors, instead having a tough pad at the front of their upper jaw. BiologyEdit  ARoe deerbrowsing tree leaves inBrastad, Sweden. DietEdit Deer arebrowsers, and feed primarily on foliage ofgrasses,sedges,forbs,shrubsandtrees, secondarily onlichensin northern latitudes during winter.[46]They have small, unspecialized stomachs byruminantstandards, and high nutrition requirements. Rather than eating and digesting vast quantities of low-grade fibrous food as, for example,sheepandcattledo, deer select easily digestible shoots, young leaves, fresh grasses, soft twigs, fruit,fungi, andlichens. The low-fibered food, after minimal fermentation and shredding, passes rapidly through the alimentary canal. The deer require a large amount of minerals such ascalciumand phosphate in order to support antler growth, and this further necessitates a nutrient-rich diet. There are some reports of deer engaging in carnivorous activity, such as eating deadalewivesalong lakeshores[47]or depredating the nests ofnorthern bobwhites.[48] ReproductionEdit Main article:Rut (mammalian reproduction) §Cervidae  Femaleelknursing young Nearly all cervids are so-calleduniparentalspecies: the fawns are only cared for by the mother, known as a doe. A doe generally has one or two fawns at a time (triplets, while not unknown, are uncommon). Mating season typically begins in later August and lasts until December. Some species mate until early March. Thegestation periodis anywhere up to ten months for the European roe deer. Most fawns are born with their fur covered with white spots, though in many species they lose these spots by the end of their first winter. In the first twenty minutes of a fawn's life, the fawn begins to take its first steps. Its mother licks it clean until it is almost free of scent, sopredatorswill not find it. Its mother leaves often to graze, and the fawn does not like to be left behind. Sometimes its mother must gently push it down with her foot.[49][bettersourceneeded]The fawn stays hidden in the grass for one week until it is strong enough to walk with its mother. The fawn and its mother stay together for about one year. A male usually leaves and never sees his mother again, but females sometimes come back with their own fawns and form small herds. DiseaseEdit In some areas of the UK, deer (especiallyfallow deerdue to theirgregarious behaviour) have been implicated as a possible reservoir for transmission ofbovine tuberculosis,[50][51]a disease which in the UK in 2005 cost £90million in attempts to eradicate.[52]In New Zealand, deer are thought to be important as vectors picking upM. bovisin areas where brushtail possumsTrichosurus vulpeculaare infected, and transferring it to previously uninfected possums when their carcasses are scavenged elsewhere.[53]The white-tailed deerOdocoileus virginianushas been confirmed as the sole maintenance host in the Michigan outbreak of bovine tuberculosis which remains a significant barrier to the US nationwide eradication of the disease in livestock.[54]Moose and deer can carryrabies.[55] Docile moose may suffer frombrain worm, ahelminthwhich drills holes through the brain in its search for a suitable place to lay its eggs. A government biologist states that "They move around looking for the right spot and never really find it." Deer appear to be immune to this parasite; it passes through the digestive system and is excreted in the feces. The parasite is not screened by the moose intestine, and passes into the brain where damage is done that is externally apparent, both in behaviour and in gait.[55] Deer, elk and moose in North America may suffer fromchronic wasting disease, which was identified at aColoradolaboratory in the 1960s and is believed to be a prion disease. Out of an abundance of caution hunters are advised to avoid contact withspecified risk material(SRM) such as the brain, spinal column or lymph nodes. Deboning the meat when butchering and sanitizing the knives and other tools used to butcher are amongst other government recommendations.[56] EvolutionEdit Deer are believed to have evolved from antlerless,tuskedancestors that resembled modernduikersand diminutive deer in the earlyEocene, and gradually developed into the first antlered cervoids (thesuperfamilyof cervids and related extinct families) in theMiocene. Eventually, with the development of antlers, the tusks as well as the upperincisorsdisappeared. Thus, evolution of deer took nearly 30 million years. BiologistValerius Geistsuggests evolution to have occurred in stages. There are not many prominent fossils to trace this evolution, but only fragments of skeletons and antlers that might be easily confused with false antlers of non-cervid species.[14][57] EoceneEdit Theruminants, ancestors of the Cervidae, are believed to have evolved fromDiacodexis, the earliest known artiodactyl (even-toed ungulate), 50–55 Mya in the Eocene.[58]Diacodexis, nearly the size of arabbit, featured thetalus bonecharacteristic of all moderneven-toed ungulates. This ancestor and its relatives occurred throughout North America and Eurasia, but were on the decline by at least 46 Mya.[58][59]Analysis of a nearly complete skeleton ofDiacodexisdiscovered in 1982 gave rise to speculation that this ancestor could be closer to the non-ruminants than the ruminants.[60]Andromeryxis another prominent prehistoric ruminant, but appears to be closer to thetragulids.[61] OligoceneEdit  Leptomeryx The formation of theHimalayasand theAlpsbrought about significant geographic changes. This was the chief reason behind the extensive diversification of deer-like forms and the emergence of cervids from theOligoceneto the earlyPliocene.[62]The latter half of the Oligocene (28–34 Mya) saw the appearance of the EuropeanEumeryxand the North AmericanLeptomeryx. The latter resembled modern-day bovids and cervids in dental morphology (for instance, it hadbrachyodontmolars), while the former was moreadvanced.[63]Other deer-like forms included the North AmericanBlastomeryxand the EuropeanDremotherium; these sabre-toothed animals are believed to have been the direct ancestors of all modern antlered deer, though they themselves lacked antlers.[64]Another contemporaneous form was the four-hornedprotoceratidProtoceras, that was replaced bySyndyocerasin the Miocene; these animals were unique in having a horn on the nose.[57]Late Eocene fossils dated approximately 35 million years ago, which were found in North America, show thatSyndyocerashad bony skull outgrowths that resembled non-deciduous antlers.[65] MioceneEdit Fossil evidence suggests that the earliest members of the superfamily Cervoidea appeared in Eurasia in the Miocene.Dicrocerus,EuproxandHeteroproxwere probably the first antlered cervids.[66]Dicrocerusfeatured single-forked antlers that were shed regularly.[67]Stephanocemashad more developed and diffuse ("crowned") antlers.[68]Procervulus(Palaeomerycidae) also possessed antlers that were not shed.[69]Contemporary forms such as themerycodontineseventually gave rise to the modern pronghorn.[70] The Cervinae emerged as the first group of extant cervids around 7–9 Mya, during the late Miocene in central Asia. The tribe Muntiacini made its appearance as†Muntiacus leilaoensisaround 7–8 Mya;[71]The early muntjacs varied in size–as small as hares or as large as fallow deer. They had tusks for fighting and antlers for defence.[14]Capreolinae followed soon after; Alceini appeared 6.4–8.4 Mya.[72]Around this period, theTethys Oceandisappeared to give way to vast stretches of grassland; these provided the deer with abundant protein-rich vegetation that led to the development of ornamental antlers and allowed populations to flourish and colonise areas.[14][62]As antlers had become pronounced, the canines were either lost or became poorly represented (as in elk), probably because diet was no longerbrowse-dominated and antlers were better display organs. In muntjac and tufted deer, the antlers as well as the canines are small. The tragulids possess long canines to this day.[59] PlioceneEdit  Cervocerus novorossiae With the onset of thePliocene, the global climate became cooler. A fall in the sea-level led to massive glaciation; consequently, grasslands abounded in nutritious forage. Thus a new spurt in deer populations ensued.[14][62]The oldest member of Cervini,†Cervocerus novorossiae, appeared around the transition from Miocene to Pliocene (4.2–6 Mya) in Eurasia;[73]cervine fossils from early Pliocene to as late as thePleistocenehave been excavated in China[74]and the Himalayas.[75]WhileCervusandDamaappeared nearly 3 Mya,Axisemerged during the late Pliocene–Pleistocene. The tribes Capreolini and Rangiferini appeared around 4–7 Mya.[72] Around 5 Mya, the rangiferina†Bretziaand†Eocoileuswere the first cervids to reach North America.[72]This implies the Bering Strait could be crossed during the late Miocene–Pliocene; this appears highly probable as thecamelidsmigrated into Asia from North America around the same time.[76]Deer invaded South America in the late Pliocene (2.5–3 Mya) as part of theGreat American Interchange, thanks to the recently formedIsthmus of Panama, and emerged successful due to the small number of competing ruminants in the continent.[77] PleistoceneEdit Large deer with impressive antlers evolved during the early Pleistocene, probably as a result of abundant resources to drive evolution.[14]The early Pleistocene cervid†Eucladoceroswas comparable in size to the modern elk.[78]†Megaloceros(Pliocene–Pleistocene) featured theIrish elk(M. giganteus), one of thelargest known cervids. The Irish elk reached2 metres (6+1⁄2ft) at the shoulder and had heavy antlers that spanned 3.6 metres (11ft 10in) from tip to tip.[79]These large animals are thought to have faced extinction due to conflict betweensexual selectionfor large antlers and body andnatural selectionfor a smaller form.[80]Meanwhile, the moose and reindeer radiated into North America from Siberia.[81] Taxonomy and classificationEdit  Cervid skull Further information:List of cervids Deer constitute theartiodactylfamilyCervidae. This family was firstdescribedby German zoologistGeorg August GoldfussinHandbuch der Zoologie(1820). Threesubfamiliesare recognised: Capreolinae (first described by the English zoologistJoshua Brookesin 1828), Cervinae (described by Goldfuss) and Hydropotinae (first described by French zoologistÉdouard Louis Trouessartin 1898).[8][82] Other attempts at the classification of deer have been based on morphological andgeneticdifferences.[57]The Anglo-Irish naturalistVictor Brookesuggested in 1878 that deer could be bifurcated into two classes on the according to the features of the second and fifthmetacarpal bonesof their forelimbs: Plesiometacarpalia (most Old World deer) and Telemetacarpalia (most New World deer). He treated themusk deeras a cervid, placing it under Telemetacarpalia. While the telemetacarpal deer showed only those elements located far from the joint, the plesiometacarpal deer retained the elements closer to the joint as well.[83]Differentiation on the basis ofdiploidnumber ofchromosomesin the late 20th century has been flawed by several inconsistencies.[57] In 1987, the zoologistsColin GrovesandPeter Grubbidentified three subfamilies: Cervinae, Hydropotinae and Odocoileinae; they noted that the hydropotines lack antlers, and the other two subfamilies differ in their skeletal morphology.[84]They reverted from this classification in 2000.[85] Molecular phylogenetic analyses since the latter half of the 2000s all show thathydropotesis a sister taxon ofCapreolus, and “Hydropotinae” became outdated subfamily.[86][87][88][89][90] External relationshipsEdit Until 2003, it was understood that the familyMoschidae(musk deer) wassisterto Cervidae. Then aphylogeneticstudy by Alexandre Hassanin (ofNational Museum of Natural History, France) and colleagues, based onmitochondrialandnuclearanalyses, revealed that Moschidae andBovidaeform acladesister to Cervidae. According to the study, Cervidaedivergedfrom the Bovidae-Moschidae clade 27 to 28 million years ago.[91]The followingcladogramis based on the 2003 study.[91] RuminantiaTragulina Tragulidae  Pecora  Antilocapridae    Giraffidae     Cervidae     Bovidae    Moschidae       Internal relationshipsEdit A 2006phylogeneticstudy of the internal relationships in Cervidae by Clément Gilbert and colleagues divided the family into two major clades: Capreolinae (telemetacarpal or New World deer) and Cervinae (plesiometacarpal or Old World deer). Studies in the late 20th century suggested a similar bifurcation in the family. This as well as previous studies supportmonophylyin Cervinae, while Capreolinae appearsparaphyletic. The 2006 study identified two lineages in Cervinae, Cervini (comprising the generaAxis,Cervus,DamaandRucervus) and Muntiacini (MuntiacusandElaphodus). Capreolinae featured three lineages, Alceini (Alcesspecies), Capreolini (Capreolusand the subfamily Hydropotinae) and Rangiferini (Blastocerus,Hippocamelus,Mazama,Odocoileus,PuduandRangiferspecies). The following cladogram is based on the 2006 study.[72] CervidaeCervinae(OldWorlddeer)Muntiacini  Reeves's muntjac    Tufted deer   Cervini    Common fallow deer    Persian fallow deer        Rusa    Sambar      Red deer    Thorold's deer    Sika deer    Elk(Wapiti)       Eld's deer    Père David's deer        Barasingha     Indian hog deer    Chital      Capreolinae(NewWorlddeer)Rangiferini  Reindeer(Caribou)      American red brocket     White-tailed deer    Mule deer       Marsh deer    Gray brocket    Southern pudu    Taruca     Capreolini  Roe deer    Water deer   Alceini MooseorEurasian elk     Human interactionEdit  Upper Palaeolithiccave paintingof aMegalocerosgiant deer atLascaux, 17,300 years old Further information:Deer in mythology PrehistoricEdit Deer were an important source of food for early hominids. In China,Homo erectusfed upon thesika deer, while the red deer was hunted in Germany. In theUpper Palaeolithic, the reindeer was the staple food forCro-Magnonpeople,[92]while thecave paintingsatLascauxin southwestern France include some 90 images of stags.[93]InChina, deer continued to be a main source of food for millennia even after people began farming, and it is possible that sika and other deer benefited from the frequently abandoned field sites.[94] HistoricEdit  Ancient Greekgilt-silverrhyton, 4th century BC Deer had a central role in the ancient art, culture and mythology of theHittites, theancient Egyptians, theCelts, theancient Greeks, the Asians and several others. For instance, theStag Hunt Mosaicof ancientPella, under theKingdom of Macedonia(4th century BC), possibly depictsAlexander the Greathunting a deer withHephaestion.[95]In JapaneseShintoism, the sika deer is believed to be a messenger to the gods.In China, deer are associated with great medicinal significance;deer penisis thought by some in China to haveaphrodisiacproperties.[96]Spotted deer are believed in China to accompany the god of longevity. Deer was the principal sacrificial animal for the Huichal Indians of Mexico. In medieval Europe, deer appeared in hunting scenes and coats-of-arms. Deer are depicted in many materials by various pre-Hispanic civilizations in the Andes.[92][97] The common male first nameOscaris taken from theIrish Language, where it is derived from two elements: the first,os, means "deer"; the second element,cara, means "friend". The name is borne by a famous hero ofIrish mythology—Oscar, grandson ofFionn Mac Cumhail. The name was popularised in the 18th century byJames Macpherson, creator of 'Ossianic poetry'. LiteraryEdit  In the Indian epicRamayana,Ramakills the illusionalgolden deer. Deer have been an integral part of fables and other literary works since the inception of writing. Stags were used as symbols in the latter Sumerian writings. For instance, the boat of Sumerian god Enki is named theStag of Azbu. There are several mentions of the animal in theRigvedaas well as theBible. In the Indian epicRamayana,Sitais lured by a golden deer whichRamatries to catch. In the absence of both Rama andLakshman,Ravanakidnaps Sita. Many of the allegoricalAesop's fables, such as "The Stag at the Pool", "The One-Eyed Doe" and "The Stag and a Lion", personify deer to give moral lessons. For instance, "The Sick Stag" gives the message that uncaring friends can do more harm than good.[92]TheYaquideer song accompanies the deer dance which is performed by a pascola [from the Spanish 'pascua', Easter] dancer (also known as a deer dancer). Pascolas would perform at religious and social functions many times of the year, especially during Lent and Easter.[92][98] In one ofRudolf Erich Raspe's 1785 stories ofBaron Munchausen's Narrative of his Marvellous Travels and Campaigns in Russia, the baron encounters a stag while eating cherries and, without ammunition, fires the cherry-pits at the stag with his musket, but it escapes. The next year, the baron encounters a stag with acherry treegrowing from its head; presumably this is the animal he had shot at the previous year. InChristmaslore (such as in the narrative poem "A Visit from St. Nicholas"),reindeerare often depicted pulling thesleighofSanta Claus.[99]Marjorie Kinnan Rawlings'sPulitzer Prize-winning 1938 novelThe Yearlingwas about a boy's relationship with a baby deer. The fiction bookFire Bringeris about a young fawn who goes on a quest to save the Herla, the deer kind.[100]In the 1942Walt Disney Picturesfilm,Bambiis awhite-tailed deer, while inFelix Salten's original 1923 bookBambi, a Life in the Woods, he is aroe deer. InC. S. Lewis's 1950 fantasy novelThe Lion, the Witch and the Wardrobethe adult Pevensies, now kings and queens ofNarnia, chase the White Stag on a hunt, as the Stag is said to grant its captor a wish. The hunt is key in returning the Pevensies to their home in England. In the 1979 bookThe Animals of Farthing Wood, The Great White Stag is the leader of all the animals. HeraldicEdit  Arms ofRaon-aux-Bois, France  Arms ofÅland Deer of various types appear frequently in Europeanheraldry. In the British armory, the term "stag" is typically used to refer to antlered male red deer, while "buck" indicates an antlered male fallow deer. Stags and bucks appear in a number ofattitudes, referred to as "lodged" when the deer is lying down, "trippant" when it has one leg raised, "courant" when it is running, "springing" when in the act of leaping, "statant" when it is standing with all hooves on the ground and looking ahead, and "at gaze" when otherwise statant but looking at the viewer. Stags' heads are also frequently used; these are typically portrayed without an attached neck and as facing the viewer, in which case they are termed "caboshed".[101] Examples of deer incoats of armscan be found in the arms ofHertfordshire, England, and its county town ofHertford; both are examples ofcanting arms. A deer appears on the arms of theIsraeli Postal Authority. Coats of arms featuring deer include those ofDotternhausen,Thierachern,Friolzheim,Bauen,Albstadt, andDasselin Germany; of theEarls Bathurstin England;[102]ofBalakhna, Russia; ofÅland, Finland; ofGjemnes,Hitra,Hjartdal,RendalenandVossin Norway; ofJelenia Góra, Poland; ofUmeå, Sweden; ofQueensland, Australia; ofCervera, Catalonia; of Northern Ireland; and of Chile.[citation needed] Other types of deer used in heraldry include the hind, portrayed much like the stag or buck but without antlers, as well as the reindeer and winged stags. Winged stags are used assupportersin the arms of thede Carteret family. The sea-stag, possessing the antlers, head, forelegs and upper body of a stag and the tail of amermaid, is often found in German heraldry.[101] EconomicEdit  Bronze deer,Warring States period Deer have long had economic significance to humans. Deer meat, known asvenison, is highly nutritious.[103][104]Due to the inherently wild nature and diet of deer, venison is most often obtained through deer hunting. In the United States, it is produced in small amounts compared tobeef, but still represents a significant trade. Deer hunting is a popular activity in the U.S. that can provide the hunter's family with high quality meat and generates revenue for states and the federal government from the sales of licenses, permits and tags. The 2006 survey by theU.S. Fish and Wildlife Serviceestimates that license sales generate approximately $700 million annually. This revenue generally goes to support conservation efforts in the states where the licenses are purchased. Overall, the U.S. Fish and Wildlife Service estimates that big game hunting for deer and elk generates approximately $11.8 billion annually in hunting-related travel, equipment and related expenditures.[105]Conservation laws prevent the sale of unlicensed wild game meat, although it may be donated.  Nicholas Mavrogenes,PhanariotePrinceofWallachia, riding throughBucharestin a stag−drawn carriage. Late 1780s Deer have often been bred in captivity as ornaments for parks, but only in the case of reindeer has thorough domestication succeeded.[106]By 2012, some 25,000 tons of red deer were raised on farms in North America. TheSamiof Scandinavia and theKola Peninsulaof Russia and other nomadic peoples of northern Asia use reindeer for food, clothing, and transport. Others are bred for hunting are selected based on the size of the antlers.[107]The major deer-producing countries are New Zealand, the market leader, with Ireland, Great Britain and Germany. The trade earns over $100 million annually for these countries.[108] Automobile collisions with deer can impose a significant cost on the economy. In the U.S., about 1.5million deer-vehicle collisions occur each year, according to theNational Highway Traffic Safety Administration. Those accidents cause about 150 human deaths and $1.1billion in property damage annually.[109]In Scotland, several roads including theA82, theA87and theA835have had significant enough problems withdeer vehicle collisions(DVCs) that sets of vehicle activated automatic warning signs have been installed along these roads.[110]  Leather side of aRoe deerhide The skins make a peculiarly strong, soft leather, known asbuckskin. There is nothing special about skins with the fur still on since the hair is brittle and soon falls off. The hoofs and horns are used for ornamental purposes, especially the antlers of theroe deer, which are utilized for making umbrella handles, and for similar purposes; elk horn is often employed in making knife handles. Among theInuit, the traditionaluluwomen's knife was made with an antler, horn, or ivory handle.[111]In China, a medicine is made from stag horn, and the antlers of certain species are eaten when "in the velvet".[106]Velvet antlers in medicine have been shown to have health benefits including an enhanced immune system and athletic performance, as well as being effective treatment for arthritis. Antlers can also be boiled down to release the protein gelatin, which is used as a topical treatment for skin irritation and is also used in cooking.[112] Since the early 20th century, deer have become commonly thought of as pests in New Zealand due to a lack of predators on the island causing population numbers to increase and begin encroaching on more populated areas. They compete with livestock for resources, as well as cause excess erosion and wreak havoc on wild plant species and agriculture alike. They can also have an effect on the conservation efforts of other plant and animal species, as they can critically offset the balance within an environment by drastically depleting diversity within forests.[113] Coyote males average 8 to 20kg (18 to 44lb) in weight, while females average 7 to 18kg (15 to 40lb), though size varies geographically. Northern subspecies, which average 18kg (40lb), tend to grow larger than the southern subspecies of Mexico, which average 11.5kg (25lb). Total length ranges on average from 1.0 to 1.35m (3ft 3in to 4ft 5in); comprising a tail length of 40cm (16in), with females being shorter in both body length and height.The largest coyote on record was a male killed nearAfton, Wyoming, on November19, 1937, which measured 1.5m (4ft 11in) from nose to tail, and weighed 34kg (75lb).Scent glands are located at the upper side of the base of the tail and are a bluish-black color. The color and texture of the coyote's fur vary somewhat geographically.The hair's predominant color is light gray and red orfulvous, interspersed around the body with black and white. Coyotes living at high elevations tend to have more black and gray shades than theirdesert-dwelling counterparts, which are more fulvous or whitish-gray.The coyote's fur consists of short, soft underfur and long, coarse guard hairs. The fur of northern subspecies is longer and denser than in southern forms, with the fur of some Mexican and Central American forms being almost hispid (bristly).Generally, adult coyotes (including coywolf hybrids) have a sable coat color, dark neonatal coat color, bushy tail with an activesupracaudal gland, and a white facial mask.Albinismis extremely rare in coyotes; out of a total of 750,000 coyotes killed by federal and cooperative hunters between March22, 1938, and June30, 1945, only two were albinos. The coyote is typically smaller than the gray wolf, but has longer ears and a relatively largerbraincase,as well as a thinner frame, face, and muzzle. The scent glands are smaller than the gray wolf's, but are the same color.Its fur color variation is much less varied than that of a wolf.The coyote also carries its tail downwards when running or walking, rather than horizontally as the wolf does. Coyote tracks can be distinguished from those of dogs by their more elongated, less rounded shape.Unlike dogs, the upper canines of coyotes extend past themental foramina.

In 1758, the Swedish botanist and zoologistCarl Linnaeuspublished in hisSystema Naturae, the two-word naming of species (binomial nomenclature).Canisis theLatinword meaning "dog",[15]and under thisgenus, he listed the domestic dog, thewolf, and thegolden jackal. He classified the domestic dog asCanis familiarisand, on the next page, classified the grey wolf asCanis lupus.[2]Linnaeus considered the dog to be a separate species from the wolf because of its upturning tail (cauda recurvata), which is not found in any othercanid.[16] In 1999, a study ofmitochondrial DNA(mtDNA) indicated that the domestic dog may have originated from the grey wolf, with thedingoandNew Guinea singing dogbreeds having developed at a time when human communities were more isolated from each other.[17]In the third edition ofMammal Species of the Worldpublished in 2005, themammalogistW. Christopher Wozencraftlisted under the wolfCanis lupusits wild subspecies and proposed two additional subspecies, which formed the domestic dog clade:familiaris, as named by Linnaeus in 1758 and,dingonamed by Meyer in 1793. Wozencraft includedhallstromi(the New Guinea singing dog) as another name (junior synonym) for the dingo. Wozencraft referred to the mtDNA study as one of the guides informing his decision.[3]Mammalogists have noted the inclusion offamiliarisanddingotogether under the "domestic dog" clade[18]with some debating it.[19] In 2019, a workshop hosted by theIUCN/Species Survival Commission's Canid Specialist Group considered the dingo and the New Guinea singing dog to beferalCanis familiarisand therefore did not assess them for theIUCN Red List of Threatened Species.[4] Evolution Main article:Evolution of the wolf  Location of a dog'scarnassials; the inside of the 4th upperpremolaraligns with the outside of the 1st lowermolar, working like scissor blades TheCretaceous–Paleogene extinction eventoccurred 65 million years ago and brought an end to the dinosaurs and the appearance of the first carnivorans.[20]The namecarnivoranis given to a member of the orderCarnivora. Carnivorans possess a common arrangement of teeth calledcarnassials, in which the first lowermolarand the last upperpremolarpossess blade-like enamelcrownsthat act similar to a pair of shears for cutting meat. This dental arrangement has been modified by adaptation over the past 60 million years for diets composed of meat, for crushing vegetation, or for the loss of the carnassial function altogether as in seals, sea lions, and walruses. Today, not all carnivorans arecarnivores, such as the insect-eatingAardwolf.[5] The carnivoran ancestors of the dog-likecaniformsand the cat-likefeliformsbegan their separate evolutionary paths just after the end of the dinosaurs. The first members of the dog familyCanidaeappeared 40 million years ago,[21]of which only its subfamily theCaninaesurvives today in the form of the wolf-like and fox-like canines. Within the Caninae, the first members of genusCanisappeared six million years ago,[15]the ancestors of modern domestic dogs, wolves,coyotes, and golden jackals. Domestication Main article:Domestication of the dog The earliest remains generally accepted to be those of a domesticated dog were discovered inBonn-Oberkassel, Germany. Contextual, isotopic, genetic, and morphological evidence shows that this dog was not a local wolf.[22]The dog was dated to 14,223 years ago and was found buried along with a man and a woman, all three having been sprayed with redhematitepowder and buried under large, thick basalt blocks. The dog had died ofcanine distemper.[23]Earlier remains dating back to 30,000 years ago have been described asPaleolithic dogs, but their status as dogs or wolves remains debated[24]because considerablemorphologicaldiversity existed among wolves during theLate Pleistocene.[1] This timing indicates that the dog was the first species to be domesticated[9][8]in the time ofhunter–gatherers,[7]which predates agriculture.[1]DNA sequencesshow that all ancient and modern dogs share a common ancestry and descended from an ancient, extinct wolf population which was distinct from themodern wolflineage.[6][7]Most dogs form a sister group to the remains of a LatePleistocene wolffound in theKessleroch cavenearThayngenin the canton ofSchaffhausen,Switzerland, which dates to 14,500 years ago. Themost recent common ancestorof both is estimated to be from 32,100 years ago.[25]This indicates that an extinct Late Pleistocene wolf may have been the ancestor of the dog,[8][1][26]with the modern wolf being the dog's nearest living relative.[8] The dog is a classic example of a domestic animal that likely travelled acommensalpathway into domestication.[24][27]The questions of when and where dogs were first domesticated have taxed geneticists and archaeologists for decades.[9]Genetic studies suggest a domestication process commencing over 25,000 years ago, in one or several wolf populations in either Europe, the high Arctic, or eastern Asia.[10]In 2021, aliterature reviewof the current evidenceinfersthat the dog was domesticated inSiberia23,000 years ago byancient North Siberians, then later dispersed eastward into the Americas and westward across Eurasia.[22] Breeds Main article:Dog breed Further information:Dog type  Dog breeds show a range ofphenotypic variation Dogs are the most variable mammal on earth with around 450 globally recognizeddog breeds.[10]In theVictorian era, directed humanselectiondeveloped the moderndog breeds, which resulted in a vast range of phenotypes.[8]Most breeds were derived from small numbers of founders within the last 200 years,[8][10]and since then dogs have undergone rapidphenotypicchange and were formed into today's modern breeds due toartificial selectionimposed by humans. The skull, body, and limb proportions vary significantly between breeds, with dogs displaying more phenotypic diversity than can be found within the entire order of carnivores. These breeds possess distinct traits related to morphology, which include body size, skull shape, tail phenotype, fur type and colour.[8]Their behavioural traits include guarding, herding, and hunting,[8]retrieving, and scent detection. Their personality traits include hypersocial behavior, boldness, and aggression,[10]which demonstrates the functional and behavioral diversity of dogs.[8]As a result, present day dogs are the most abundant carnivore species and are dispersed around the world.[10]The most striking example of this dispersal is that of the numerous modern breeds of European lineage during theVictorian era.[7] Biology Anatomy Main article:Dog anatomy Skeleton  A lateral view of a dog skeleton All healthy dogs, regardless of their size and type, have an identicalskeletalstructure with the exception of the number of bones in the tail, although there is significant skeletal variation between dogs of different types.[28][29]The dog's skeleton is well adapted for running; thevertebraeon the neck and back have extensions for powerful back muscles to connect to, the long ribs provide plenty of room for the heart and lungs, and the shoulders are unattached to the skeleton allowing great flexibility.[28][29] Compared to the dog's wolf-like ancestors, selective breeding since domestication has seen the dog's skeleton greatly enhanced in size for larger types asmastiffsand miniaturised for smaller types such asterriers;dwarfismhas been selectively utilised for some types where short legs are advantageous such asdachshundsandcorgis.[29]Most dogs naturally have 26 vertebrae in their tails, but some withnaturally short tailshave as few as three.[28] The dog's skull has identical components regardless of breed type, but there is significant divergence in terms of skull shape between types.[29][30]The three basic skull shapes are the elongated dolichocephalic type as seen insighthounds, the intermediate mesocephalic or mesaticephalic type, and the very short and broad brachycephalic type exemplified by mastiff type skulls.[29][30] Senses Further information:Dog anatomy §Senses A dog's senses include vision, hearing, smell, taste, touch, and sensitivity to Earth's magnetic field. Another study has suggested that dogs can see Earth's magnetic field.[31] Coat Main article:Dog coat  Dogs display wide variation in coat type, density, length, color, and composition Thecoatsof domestic dogs are of two varieties: "double" being familiar with dogs (as well as wolves) originating from colder climates, made up of a coarseguard hairand a softdown hair, or "single", with the topcoat only. Breeds may have an occasional "blaze", stripe, or "star" of white fur on their chest or underside.[32]Premature graying can occur in dogs from as early as one year of age; this is associated withimpulsive behaviors,anxiety behaviors, fear of noise, and fear of unfamiliar people or animals.[33] Tail There are many different shapes fordog tails: straight, straight up, sickle, curled, or corkscrew. As with many canids, one of the primary functions of a dog's tail is to communicate their emotional state, which can be crucial in getting along with others. In some hunting dogs the tail is traditionallydockedto avoid injuries. Health Main article:Dog health Some breeds of dogs are prone to specific genetic ailments such aselbowandhip dysplasia,blindness,deafness,pulmonic stenosis,cleft palate, andtrick knees. Two severe medical conditions significantly affecting dogs arepyometra, affectingunspayedfemales of all breeds and ages, andGastric dilatation volvulus(bloat), which affects larger breeds or deep-chested dogs. Both of these are acute conditions and can kill rapidly. Dogs are also susceptible to parasites such asfleas,ticks,mites,hookworms,tapeworms,roundworms, andheartworms, which is aroundwormspecies that lives in the hearts of dogs. Several human foods and household ingestibles are toxic to dogs, includingchocolate solids, causingtheobromine poisoning,onionsandgarlic, causingthiosulphate,sulfoxideordisulfidepoisoning,grapesandraisins,macadamia nuts, andxylitol.[34]The nicotine in tobacco can also be dangerous to dogs. Signs of ingestion can include copious vomiting (e.g., from eating cigar butts) ordiarrhea. Some other symptoms are abdominal pain, loss of coordination, collapse, or death.[35][pageneeded] Dogs are also vulnerable to some of the same health conditions as humans, includingdiabetes,dentalandheart disease,epilepsy,cancer,hypothyroidism, andarthritis. Lifespan Further information:Aging in dogs The typical lifespan of dogs varies widely among breeds, but for most, the median longevity (the age at which half the dogs in a population have died and half are still alive) ranges from 10 to 13 years.[36][37]The median longevity ofmixed-breed dogs, taken as an average of all sizes, is one or more years longer than that of purebred dogs when all breeds are averaged.[36][37][38]For dogs in England, increased body weight has been found to be negatively correlated with longevity (i.e., the heavier the dog, the shorter its lifespan), andmixed-breed dogslive on average 1.2 years longer thanpurebred dogs.[39] Reproduction Main article:Canine reproduction  A female dog nursing newborn puppies. In domestic dogs,sexual maturityhappens around six months to one year for both males and females, although this can be delayed until up to two years of age for some large breeds, and is the time at which female dogs will have their firstestrous cycle. They will experience subsequent estrous cycles semiannually, during which the body prepares forpregnancy. At the peak of the cycle, females will become estrous, mentally and physically receptive tocopulation. Because theovasurvive and can be fertilized for a week after ovulation, more than one male can sire the same litter.[12] Fertilization typically occurs two to five days after ovulation; 14–16 days after ovulation, the embryo attaches to the uterus and after seven to eight more days, a heartbeat is detectable.[40][41] Dogs bear their litters roughly 58 to 68 days afterfertilization,[12][42]with an average of 63 days, although the length of gestation can vary. An average litter consists of about sixpuppies.[43] Neutering Neuteringrefers to the sterilization of animals, usually byremoving the male's testiclesor the female'sovariesanduterus, to eliminate the ability to procreate and reducesex drive. Because ofdogs' overpopulationin some countries, many animal control agencies, such as theAmerican Society for the Prevention of Cruelty to Animals(ASPCA), advise that dogs not intended for further breeding should be neutered, so that they do not have undesired puppies that may later be euthanized.[44] According to theHumane Society of the United States, three to four million dogs and cats areeuthanizedeach year.[45]Many more are confined to cages in shelters because there are many more animals than there are homes. Spaying or castrating dogs helps keep overpopulation down.[46] Neutering reduces problems caused byhypersexuality, especially in male dogs.[47]Spayed female dogs are less likely to develop cancers affecting the mammary glands, ovaries, and other reproductive organs.[48][pageneeded]However, neutering increases the risk ofurinary incontinencein female dogs[49]andprostate cancerin males[50]andosteosarcoma,hemangiosarcoma,cruciate ligamentrupture, obesity, anddiabetes mellitusin either sex.[51] Inbreeding depression A common breeding practice for pet dogs is mating between close relatives (e.g., between half and full siblings).[52]Inbreeding depressionis considered to be due mainly to the expression of homozygous deleterious recessive mutations.[53]Outcrossing between unrelated individuals, including dogs of different breeds, results in the beneficial masking of deleterious recessive mutations in progeny.[54] In a study of seven dog breeds (theBernese Mountain Dog,Basset Hound,Cairn Terrier,Brittany,German Shepherd Dog,Leonberger, andWest Highland White Terrier), it was found that inbreeding decreases litter size and survival.[55]Another analysis of data on 42,855Dachshundlitters found that as theinbreeding coefficientincreased, litter size decreased and the percentage of stillborn puppies increased, thus indicating inbreeding depression.[56]In a study ofBoxerlitters, 22% of puppies died before reaching 7 weeks of age. Stillbirth was the most frequent cause of death, followed by infection. Mortality due to infection increased significantly with increases in inbreeding.[57] Behavior Main article:Dog behavior See also:Dog behavior §Behavior compared with other canids Dog behavior is the internally coordinated responses (actions or inactions) of the domestic dog (individuals or groups) to internal and external stimuli.[58]As the oldest domesticated species, dogs' minds inevitably have been shaped by millennia of contact with humans. As a result of this physical and social evolution, dogs have acquired the ability to understand and communicate with humans more than any other species and they are uniquely attuned to human behaviors.[13]Behavioral scientists have uncovered a surprising set of social-cognitive abilities in domestic dogs. These abilities are not possessed by the dog's closest canine relatives or other highly intelligent mammals, such asgreat apes, but rather parallel to children's social-cognitive skills.[59] Unlike other domestic species selected for production-related traits, dogs were initially selected for their behaviors.[60][61]In 2016, a study found that only 11 fixed genes showed variation between wolves and dogs. These gene variations were unlikely to have been the result of natural evolution and indicate selection on both morphology and behavior during dog domestication. These genes have been shown to affect thecatecholamine synthesispathway, with the majority of the genes affecting the fight-or-flight response[61][62](i.e., selection for tameness) and emotional processing.[61]Dogs generally show reduced fear and aggression compared with wolves.[61][63]Some of these genes have been associated with aggression in some dog breeds, indicating their importance in both the initial domestication and later in breed formation.[61]Traits of high sociability and lack of fear in dogs may include genetic modifications related toWilliams-Beuren syndromein humans, which causehypersociabilityat the expense of problem-solving ability.[64] Intelligence Main article:Dog intelligence Dog intelligence is the dog's ability to perceive information and retain it as knowledge for applying to solve problems. Studies of two dogs suggest that dogs can learn by inference and have advanced memory skills. A study withRico, aBorder Collie, showed that he knew the labels of over 200 different items. He inferred the names of novel things by exclusion learning and correctly retrieved those new items immediately and four weeks after the initial exposure. A study of another Border Collie, Chaser, documented his learning and memory capabilities. He had learned the names and could associate by verbal command over 1,000 words.[65]Dogs can read and react appropriately to human body language such as gesturing and pointing and human voice commands. One study of canine cognitive abilities found that dogs' capabilities are no more exceptional than those of other animals, such ashorses,chimpanzees, orcats.[66]One limited study of 18 household dogs found that they lacked spatial memory, and were more focussed on the "what" of a task rather than the "where".[67] Dogs demonstrate atheory of mindby engaging in deception.[68]An experimental study showed compelling evidence that Australiandingoscan outperform domestic dogs in non-social problem-solving, indicating that domestic dogs may have lost much of their original problem-solving abilities once they joined humans.[69]Another study revealed that after undergoing training to solve a simple manipulation task, dogs faced with an unsolvable version of the same problem look at the human, while socialized wolves do not.[70] Communication Main article:Dog communication  Dog sounds 0:15 A dog making noises and barking Problems playing this file? Seemedia help. Dog communication is how dogs convey information to other dogs, understand messages from humans and translate the information that dogs are transmitting.[71]: xii Communication behaviors of dogs include eye gaze, facial expression, vocalization, body posture (including movements of bodies and limbs), and gustatory communication (scents, pheromones, and taste). Humans communicate to dogs by using vocalization, hand signals, and body posture. Ecology Population The dog is probably the most widely abundant largecarnivoranliving in the human environment.[72][73]In 2013, the estimated global dog population was between 700 million[74]and 987 million.[75]About 20% of dogs live as pets in developed countries.[76]In the developing world, dogs are more commonly feral or communally owned, with pet dogs uncommon. Most of these dogs live their lives as scavengers and have never been owned by humans, with one study showing their most common response when approached by strangers is to run away (52%) or respond aggressively (11%).[77]Little is known about these dogs, or the dogs in developed countries that are feral, strays, or are in shelters because the great majority of modern research on dog cognition has focused on pet dogs living in human homes.[78] Competitors and predators Although dogs are the most abundant and widely distributed terrestrial carnivores, feral andfree-ranging dogs' potentialto compete with other large carnivores is limited by their strong association with humans.[72]For example, a review of the studies in dogs' competitive effects onsympatriccarnivores did not mention any research on competition between dogs and wolves.[79][80]Although wolves are known to kill dogs, they tend to live in pairs or in small packs in areas where they are highly persecuted, giving them a disadvantage facing large dog groups.[79][81] Wolves kill dogs wherever they are found together.[82]In some instances, wolves have displayed an uncharacteristic fearlessness of humans and buildings when attacking dogs to the extent that they have to be beaten off or killed.[83]Although the numbers of dogs killed each year are relatively low, it induces a fear of wolves entering villages and farmyards to take dogs and losses of dogs to wolves have led to demands for more liberal wolf hunting regulations.[79] Coyotesandbig catshave also been known to attack dogs. In particular,leopardsare known to have a preference for dogs and have been recorded to kill and consume them, no matter what their size.[84]Siberian tigersin theAmur Riverregion have killed dogs in the middle of villages. This indicates that the dogs were targeted. Amur tigers will not tolerate wolves as competitors within their territories, and the tigers could be considering dogs in the same way.[85]Striped hyenasare known to kill dogs in their range.[86] Diet See also:Dog food  AGolden Retrievergnawing on a pig's foot Dogs have been described asomnivores.[12][87][88]Compared to wolves, dogs from agricultural societies haveextra copies of amylaseand other genes involved in starch digestion that contribute to an increased ability to thrive on a starch-rich diet.[11]Similar to humans, some dog breeds produce amylase in theirsalivaand are classified as having a high starch diet.[89]However, more like cats and less like other omnivores, dogs can only producebile acidwithtaurineand they cannot producevitamin D, which they obtain from animal flesh. Also more like cats, dogs requirearginineto maintain its nitrogen balance. These nutritional requirements place dogs halfway between carnivores and omnivores.[90] Range As a domesticated or semi-domesticated animal, the dog is nearly universal among human societies. Notable exceptions once included: TheAboriginal Tasmanians, who were separated from Australia before the arrival ofdingoson that continent TheAndamanese peoples, who were isolated whenrising sea levelscovered the land bridge to Myanmar TheFuegians, who instead domesticated theFuegian dog, a different canid species Individual Pacific islands whose maritime settlers did not bring dogs, or where dogs died out after original settlement, notably theMariana Islands,[91]Palau[92]and most of theCaroline Islandswith exceptions such asFais IslandandNukuoro,[93]theMarshall Islands,[94]theGilbert Islands,[94]New Caledonia,[95]Vanuatu,[95][96]Tonga,[96]Marquesas,[96]Mangaiain theCook Islands,Rapa ItiinFrench Polynesia,Easter Island,[96]theChatham Islands[97]andPitcairn Island(settled by theBountymutineers, who killed off their dogs to escape discovery by passing ships).[98] Dogs were introduced toAntarcticaassled dogs, but were later outlawed by international agreement due to the possible risk of spreading infections.[99] Roles with humans Domestic dogs inherited complex behaviors, such asbite inhibition, from their wolf ancestors, which would have beenpack hunterswith a complex body language. These sophisticated forms of social cognition and communication may account for their trainability, playfulness and ability to fit into human households and social situations. These attributes have given dogs a relationship with humans that has enabled them to become one of the most successful animals today.[100] The dogs' value to early human hunter-gatherers led to them quickly becoming ubiquitous across world cultures. Dogs perform many roles for people, such ashunting,herding,pulling loads,protection,assisting policeand themilitary,companionshipandaiding disabled individuals. This influence on human society has given them the nickname "man's best friend" in the Western world. In some cultures, however, dogsare also a source of meat.[101][102] Pets  Siberian Huskiesarepack animalsthat still enjoy some human companionship It is estimated that three-quarters of the world's dog population lives in the developing world as feral, village, or community dogs, with pet dogs uncommon.[103][pageneeded] "The most widespread form of interspecies bonding occurs between humans and dogs"[104]and the keeping of dogs as companions, particularly by elites, has a long history.[14]Pet dog populations grew significantly afterWorld War IIas suburbanization increased.[14]In the 1950s and 1960s, dogs were kept outside more often than they tend to be today[105](the expression "in the doghouse" - recorded since 1932[106]- to describe exclusion from the group implies a distance between thedoghouseand the home) and were still primarily functional, acting as a guard, children's playmate, or walking companion. From the 1980s, there have been changes in the pet dog's role, such as the increased role of dogs in the emotional support of their human guardians.[107][pageneeded]People and their dogs have become increasingly integrated and implicated in each other's lives[108][pageneeded]to the point where pet dogs actively shape how a family and home are experienced.[109] There have been two significant trends occurring within the second half of the 20th century in pet dogs' changing status. The first has been"commodification", shaping it to conform to social expectations of personality and behavior.[109]The second has been the broadening of the family's concept and the home to include dogs-as-dogs within everyday routines and practices.[109] A vast range of commodity forms aims to transform a pet dog into an ideal companion.[110]The list of goods, services, and places available is enormous: from dog perfumes, couture, furniture and housing to dog groomers, therapists, trainers and caretakers, dog cafes, spas, parks and beaches and dog hotels, airlines and cemeteries.[110]Dog training books, classes, and television programs proliferated as the process of commodifying the pet dog continued.[111] The majority of contemporary dog owners describe their pet as part of the family, although some ambivalence about the relationship is evident in the popular reconceptualization of the dog-human family as a pack.[109]Some dog trainers, such as on the television programDog Whisperer, have promoted adominance modelof dog-human relationships. However, it has been disputed that "trying to achieve status" is characteristic of dog-human interactions.[112]The idea of the "alpha dog" trying to be dominant is based on a disproved theory about wolf packs.[113][114]Pet dogs play an active role in family life; for example, a study of conversations in dog-human families showed how family members use the dog as a resource, talking to the dog, or talking through the dog; to mediate their interactions with each other.[115] Increasingly, human family-members engage in activities centered on the dog's perceived needs and interests, or in which the dog is an integral partner, such asdog dancinganddog yoga.[110] According to statistics published by theAmerican Pet Products Manufacturers Associationin the National Pet Owner Survey in 2009–2010, an estimated 77.5million people in the United States have pet dogs.[116]The same source shows that nearly 40% of American households own at least one dog, of which 67% own just one dog, 25% two dogs and nearly 9% more than two dogs. There does not seem to be anygender preferenceamong dogs as pets, as the statistical data reveal an equal number of male and female pet dogs. Although several programs promotepet adoption, less than one-fifth of the owned dogs come fromshelters.[116] A study usingmagnetic resonance imaging(MRI) to compare humans and dogs showed that dogs have the same response to voices and use the same parts of the brain as humans do. This gives dogs the ability to recognize human emotional sounds, making them friendly social pets to humans.[117] Workers Dogs have lived and worked with humans in many roles. In addition to dogs' role as companion animals, dogs have been bred for herding livestock (collies,sheepdogs),[118][pageneeded][12]hunting (hounds, pointers)[119][pageneeded]and rodent control (terriers).[12]Other types ofworking dogsincludesearch and rescue dogs,[120]detection dogstrained to detectillicit drugs[121]orchemical weapons;[122]guard dogs; dogs who assist fishermen with the use of nets; and dogs that pull loads.[12]In 1957, the dogLaikabecame the first animal to be launched intoEarth orbit, aboard theSoviets'Sputnik 2; she died during the flight.[123][124] Various kinds ofservice dogsandassistance dogs, includingguide dogs,hearing dogs,mobility assistance dogsandpsychiatric service dogs, assist individuals with disabilities.[125][126]Some dogs owned by people with epilepsy have been shown to alert their handler when the handler shows signs of an impending seizure, sometimes well in advance of onset, allowing the guardian to seek safety, medication, or medical care.[127] Athletes and models See also:Conformation show People often enter their dogs in competitions, such as breed-conformation shows orsports, including racing, sledding and agility competitions. In conformation shows, also referred to as breed shows, a judge familiar with the specific dog breed evaluates individual purebred dogs for conformity with their established breed type as described in the breed standard. As the breed standard only deals with the dog's externally observable qualities (such as appearance, movement and temperament), separately tested qualities (such as ability or health) are not part of the judging in conformation shows. Food Main article:Dog meat Dog meat is consumed in someEast Asiancountries, includingKorea,[128][pageneeded]China,[101]Vietnam[102]and thePhilippines,[129]which dates back to antiquity.[130]Based on limited data, it is estimated that 13–16million dogs are killed and consumed in Asia every year.[131]In China, debates have ensued over banning the consumption of dog meat.[132]Following the Sui and Tang dynasties of the first millennium, however, people living on northern China's plains began to eschew eating dogs, which is likely due to Buddhism and Islam's spread, two religions that forbade the consumption of certain animals, including the dog. As members of the upper classes shunned dog meat, it gradually became a social taboo to eat it, even though the general population continued to consume it for centuries afterward.[133]Dog meat is also consumed in some parts of Switzerland.[134]Other cultures, such asPolynesiaandpre-Columbian Mexico, also consumed dog meat in their history. Dog fat is also reportedly believed to be beneficial for the lungs in some parts of Poland[135][136]and Central Asia.[137][138]Proponents of eating dog meat have argued that placing a distinction between livestock and dogs is Western hypocrisy and that there is no difference in eating different animals' meat.[139][140][141][142] In Korea, the primary dog breed raised for meat, theNureongi, differs from those breeds raised for pets that Koreans may keep in their homes.[143] The most popular Korean dog dish is calledbosintang, a spicy stew meant to balance the body's heat during the summer months. Followers of the custom claim this is done to ensure good health by balancing one'sgi, or the body's vital energy. A 19th-century version of bosintang explains that the dish is prepared by boiling dog meat withscallionsand chili powder. Variations of the dish contain chicken and bamboo shoots. While the dishes are still prevalent in Korea with a segment of the population, dog is not as widely consumed as beef, pork and chicken.[143] Health risks Further information:Dog bite,Canine vector-borne disease, andDog bite prevention In 2018, theWHOreported that 59,000 people died globally fromrabies, with 59.6% in Asia and 36.4% in Africa. Rabies is a disease for which dogs are the most important vector.[144]Significant dog bites affect tens of millions of people globally each year. Children in mid-to-late childhood are the largest percentage bitten by dogs, with a greater risk of injury to the head and neck. They are more likely to need medical treatment and have the highest death rate.[145]Sharp claws with powerful muscles behind them can lacerate flesh in a scratch that can lead to serious infections.[146] In theU.S.,catsand dogs are a factor in more than 86,000 falls each year.[147]It has been estimated that around 2% of dog-related injuries treated in U.K. hospitals are domestic accidents. The same study found that while dog involvement in road traffic accidents was difficult to quantify, dog-associated road accidents involving injury more commonly involved two-wheeled vehicles.[148] Toxocara canis(dogroundworm) eggs in dog feces can causetoxocariasis. In the United States, about 10,000 cases ofToxocarainfection are reported in humans each year, and almost 14% of the U.S. population is infected.[149]Untreated toxocariasis can cause retinal damage and decreased vision.[150]Dog feces can also containhookwormsthat causecutaneous larva migransin humans.[151][152] Health benefits  Walking a dog Dogs suffer from the same common disorders as humans; these include cancer, diabetes, heart disease and neurologic disorders. Their pathology is similar to humans, as is their response to treatment and their outcomes. Researchers are identifying the genes associated with dog diseases similar to human disorders, but lack mouse models to find cures for both dogs and humans. The genes involved in canine obsessive-compulsive disorders led to the detection of four genes in humans' related pathways.[10] The scientific evidence is mixed as to whether a dog's companionship can enhance human physical health and psychological well-being.[153]Studies suggesting that there are benefits to physical health and psychological well-being[154]have been criticized for being poorly controlled.[155]It found that "the health of elderly people is related to their health habits and social supports but not to their ownership of, or attachment to, a companion animal." Earlier studies have shown that people who keep pet dogs or cats exhibit better mental and physical health than those who do not, making fewer visits to the doctor and being less likely to be on medication than non-guardians.[156] A 2005 paper states "recent research has failed to support earlier findings that pet ownership is associated with a reduced risk of cardiovascular disease, a reduced use of general practitioner services, or any psychological or physical benefits on health for community dwelling older people. Research has, however, pointed to significantly less absenteeism from school through sickness among children who live with pets."[153]In one study, new guardians reported a highly significant reduction in minor health problems during the first month following pet acquisition. This effect was sustained in those with dogs through to the end of the study.[157] People with pet dogs took considerably more physical exercise than those with cats and those without pets. The results provide evidence that keeping pets may have positive effects on human health and behavior and that for guardians of dogs, these effects are relatively long-term.[157]Pet guardianship has also been associated with increased coronary artery disease survival. Human guardians are significantly less likely to die within one year of an acute myocardial infarction than those who did not own dogs.[158]The association between dog ownership and adult physical activity levels has been reviewed by several authors.[159][160] The health benefits of dogs can result from contact with dogs in general, not solely from having dogs as pets. For example, when in a pet dog's presence, people show reductions in cardiovascular, behavioral and psychological indicators of anxiety.[161]Other health benefits are gained from exposure to immune-stimulating microorganisms, which can protect against allergies and autoimmune diseases according to thehygiene hypothesis. The benefits of contact with a dog also include social support, as dogs cannot only provide companionship and social support themselves but also act as facilitators of social interactions between humans.[162]One study indicated that wheelchair users experience more positive social interactions with strangers when accompanied by a dog than when they are not.[163]In 2015, a study found that pet owners were significantly more likely to get to know people in their neighborhood than non-pet owners.[164] Using dogs and other animals as a part of therapy dates back to the late 18th century, when animals were introduced into mental institutions to help socialize patients with mental disorders.[165]Animal-assisted intervention research has shown that animal-assisted therapy with a dog can increase social behaviors, such as smiling and laughing, among people with Alzheimer's disease.[166]One study demonstrated that children with ADHD and conduct disorders who participated in an education program with dogs and other animals showed increased attendance, increased knowledge and skill objectives and decreased antisocial and violent behavior compared with those not in an animal-assisted program.[167] Cultural importance Main articles:Cultural depictions of dogsandDogs in religion Further information:List of fictional dogs  Cerberus, with the gluttons inDante'sThird Circle of Hell.William Blake. Dogs were depicted to symbolizeguidance,protection,loyalty,fidelity,faithfulness,alertness, andlove.[168]In ancientMesopotamia, from theOld Babylonian perioduntil theNeo-Babylonian, dogs were the symbol ofNinisina, the goddess of healing and medicine,[169]and her worshippers frequently dedicated small models of seated dogs to her.[169]In theNeo-Assyrianand Neo-Babylonian periods, dogs were used as emblems of magical protection.[169]InChina,KoreaandJapan, dogs are viewed as kind protectors.[170] In mythology, dogs often serve as pets or as watchdogs.[170]Stories of dogs guarding the gates of the underworld recur throughout Indo-European mythologies[171][172]and may originate fromProto-Indo-European religion.[171][172]InGreek mythology,Cerberusis a three-headed,dragon-tailed watchdog who guards the gates ofHades.[170]Dogs are also associated with the Greek goddessHecate.[173]InNorse mythology, a bloody, four-eyed dog calledGarmrguardsHelheim.[170]InPersian mythology, two four-eyed dogs guard theChinvat Bridge.[170]InWelsh mythology,Annwnis guarded byCŵn Annwn.[170]InHindu mythology,Yama, the god of death, owns two watchdogs who have four eyes. They are said to watch over the gates ofNaraka.[174]A black dog is also considered to be thevahana(vehicle) ofBhairava(an incarnation of Shiva).[175] InChristianity, dogs represent faithfulness.[170]Within theRoman Catholicdenomination specifically, the iconography ofSaint Dominicincludes a dog, after the hallow's mother dreamt of a dog springing from her womb and becoming pregnant shortly after that.[176]As such, theDominican Order(Ecclesiastical Latin:Domini canis) means "dog of the Lord" or "hound of the Lord" (Ecclesiastical Latin:Domini canis).[176]In Christian folklore, achurch grimoften takes the form of a black dog to guard Christian churches and theirchurchyardsfromsacrilege.[177]Jewish lawdoes not prohibit keeping dogs and other pets.[178]Jewish law requires Jews to feed dogs (and other animals that they own) before themselves and make arrangements for feeding them before obtaining them.[178]The view on dogs inIslamis mixed, with some schools of thought viewing it as unclean,[170]althoughKhaled Abou El Fadlstates that this view is based on "pre-Islamic Arab mythology" and "a tradition to be falsely attributed to the Prophet."[179]Therefore, Sunni Malaki and Hanafi jurists permit the trade of and keeping of dogs as pets.[180]

Alligators sound very high.

Otters vs monitor.

Roasters need a mate.

Deer stuck with net.

Mom caracal grooming her cubs.

Liking cat.

Curious street dogs puppy.

Backyard deer and fawn.

Street dog puppies playing.

Injured the street dog.

Feeding the fawn in forest.

In 1758, the Swedish botanist and zoologistCarl Linnaeuspublished in hisSystema Naturae, the two-word naming of species (binomial nomenclature).Canisis theLatinword meaning "dog",[15]and under thisgenus, he listed the domestic dog, thewolf, and thegolden jackal. He classified the domestic dog asCanis familiarisand, on the next page, classified the grey wolf asCanis lupus.[2]Linnaeus considered the dog to be a separate species from the wolf because of its upturning tail (cauda recurvata), which is not found in any othercanid.[16] In 1999, a study ofmitochondrial DNA(mtDNA) indicated that the domestic dog may have originated from the grey wolf, with thedingoandNew Guinea singing dogbreeds having developed at a time when human communities were more isolated from each other.[17]In the third edition ofMammal Species of the Worldpublished in 2005, themammalogistW. Christopher Wozencraftlisted under the wolfCanis lupusits wild subspecies and proposed two additional subspecies, which formed the domestic dog clade:familiaris, as named by Linnaeus in 1758 and,dingonamed by Meyer in 1793. Wozencraft includedhallstromi(the New Guinea singing dog) as another name (junior synonym) for the dingo. Wozencraft referred to the mtDNA study as one of the guides informing his decision.[3]Mammalogists have noted the inclusion offamiliarisanddingotogether under the "domestic dog" clade[18]with some debating it.[19] In 2019, a workshop hosted by theIUCN/Species Survival Commission's Canid Specialist Group considered the dingo and the New Guinea singing dog to beferalCanis familiarisand therefore did not assess them for theIUCN Red List of Threatened Species.[4] Evolution Main article:Evolution of the wolf  Location of a dog'scarnassials; the inside of the 4th upperpremolaraligns with the outside of the 1st lowermolar, working like scissor blades TheCretaceous–Paleogene extinction eventoccurred 65 million years ago and brought an end to the dinosaurs and the appearance of the first carnivorans.[20]The namecarnivoranis given to a member of the orderCarnivora. Carnivorans possess a common arrangement of teeth calledcarnassials, in which the first lowermolarand the last upperpremolarpossess blade-like enamelcrownsthat act similar to a pair of shears for cutting meat. This dental arrangement has been modified by adaptation over the past 60 million years for diets composed of meat, for crushing vegetation, or for the loss of the carnassial function altogether as in seals, sea lions, and walruses. Today, not all carnivorans arecarnivores, such as the insect-eatingAardwolf.[5] The carnivoran ancestors of the dog-likecaniformsand the cat-likefeliformsbegan their separate evolutionary paths just after the end of the dinosaurs. The first members of the dog familyCanidaeappeared 40 million years ago,[21]of which only its subfamily theCaninaesurvives today in the form of the wolf-like and fox-like canines. Within the Caninae, the first members of genusCanisappeared six million years ago,[15]the ancestors of modern domestic dogs, wolves,coyotes, and golden jackals. Domestication Main article:Domestication of the dog The earliest remains generally accepted to be those of a domesticated dog were discovered inBonn-Oberkassel, Germany. Contextual, isotopic, genetic, and morphological evidence shows that this dog was not a local wolf.[22]The dog was dated to 14,223 years ago and was found buried along with a man and a woman, all three having been sprayed with redhematitepowder and buried under large, thick basalt blocks. The dog had died ofcanine distemper.[23]Earlier remains dating back to 30,000 years ago have been described asPaleolithic dogs, but their status as dogs or wolves remains debated[24]because considerablemorphologicaldiversity existed among wolves during theLate Pleistocene.[1] This timing indicates that the dog was the first species to be domesticated[9][8]in the time ofhunter–gatherers,[7]which predates agriculture.[1]DNA sequencesshow that all ancient and modern dogs share a common ancestry and descended from an ancient, extinct wolf population which was distinct from themodern wolflineage.[6][7]Most dogs form a sister group to the remains of a LatePleistocene wolffound in theKessleroch cavenearThayngenin the canton ofSchaffhausen,Switzerland, which dates to 14,500 years ago. Themost recent common ancestorof both is estimated to be from 32,100 years ago.[25]This indicates that an extinct Late Pleistocene wolf may have been the ancestor of the dog,[8][1][26]with the modern wolf being the dog's nearest living relative.[8] The dog is a classic example of a domestic animal that likely travelled acommensalpathway into domestication.[24][27]The questions of when and where dogs were first domesticated have taxed geneticists and archaeologists for decades.[9]Genetic studies suggest a domestication process commencing over 25,000 years ago, in one or several wolf populations in either Europe, the high Arctic, or eastern Asia.[10]In 2021, aliterature reviewof the current evidenceinfersthat the dog was domesticated inSiberia23,000 years ago byancient North Siberians, then later dispersed eastward into the Americas and westward across Eurasia.[22] Breeds Main article:Dog breed Further information:Dog type  Dog breeds show a range ofphenotypic variation Dogs are the most variable mammal on earth with around 450 globally recognizeddog breeds.[10]In theVictorian era, directed humanselectiondeveloped the moderndog breeds, which resulted in a vast range of phenotypes.[8]Most breeds were derived from small numbers of founders within the last 200 years,[8][10]and since then dogs have undergone rapidphenotypicchange and were formed into today's modern breeds due toartificial selectionimposed by humans. The skull, body, and limb proportions vary significantly between breeds, with dogs displaying more phenotypic diversity than can be found within the entire order of carnivores. These breeds possess distinct traits related to morphology, which include body size, skull shape, tail phenotype, fur type and colour.[8]Their behavioural traits include guarding, herding, and hunting,[8]retrieving, and scent detection. Their personality traits include hypersocial behavior, boldness, and aggression,[10]which demonstrates the functional and behavioral diversity of dogs.[8]As a result, present day dogs are the most abundant carnivore species and are dispersed around the world.[10]The most striking example of this dispersal is that of the numerous modern breeds of European lineage during theVictorian era.[7] Biology Anatomy Main article:Dog anatomy Skeleton  A lateral view of a dog skeleton All healthy dogs, regardless of their size and type, have an identicalskeletalstructure with the exception of the number of bones in the tail, although there is significant skeletal variation between dogs of different types.[28][29]The dog's skeleton is well adapted for running; thevertebraeon the neck and back have extensions for powerful back muscles to connect to, the long ribs provide plenty of room for the heart and lungs, and the shoulders are unattached to the skeleton allowing great flexibility.[28][29] Compared to the dog's wolf-like ancestors, selective breeding since domestication has seen the dog's skeleton greatly enhanced in size for larger types asmastiffsand miniaturised for smaller types such asterriers;dwarfismhas been selectively utilised for some types where short legs are advantageous such asdachshundsandcorgis.[29]Most dogs naturally have 26 vertebrae in their tails, but some withnaturally short tailshave as few as three.[28] The dog's skull has identical components regardless of breed type, but there is significant divergence in terms of skull shape between types.[29][30]The three basic skull shapes are the elongated dolichocephalic type as seen insighthounds, the intermediate mesocephalic or mesaticephalic type, and the very short and broad brachycephalic type exemplified by mastiff type skulls.[29][30] Senses Further information:Dog anatomy §Senses A dog's senses include vision, hearing, smell, taste, touch, and sensitivity to Earth's magnetic field. Another study has suggested that dogs can see Earth's magnetic field.[31] Coat Main article:Dog coat  Dogs display wide variation in coat type, density, length, color, and composition Thecoatsof domestic dogs are of two varieties: "double" being familiar with dogs (as well as wolves) originating from colder climates, made up of a coarseguard hairand a softdown hair, or "single", with the topcoat only. Breeds may have an occasional "blaze", stripe, or "star" of white fur on their chest or underside.[32]Premature graying can occur in dogs from as early as one year of age; this is associated withimpulsive behaviors,anxiety behaviors, fear of noise, and fear of unfamiliar people or animals.[33] Tail There are many different shapes fordog tails: straight, straight up, sickle, curled, or corkscrew. As with many canids, one of the primary functions of a dog's tail is to communicate their emotional state, which can be crucial in getting along with others. In some hunting dogs the tail is traditionallydockedto avoid injuries. Health Main article:Dog health Some breeds of dogs are prone to specific genetic ailments such aselbowandhip dysplasia,blindness,deafness,pulmonic stenosis,cleft palate, andtrick knees. Two severe medical conditions significantly affecting dogs arepyometra, affectingunspayedfemales of all breeds and ages, andGastric dilatation volvulus(bloat), which affects larger breeds or deep-chested dogs. Both of these are acute conditions and can kill rapidly. Dogs are also susceptible to parasites such asfleas,ticks,mites,hookworms,tapeworms,roundworms, andheartworms, which is aroundwormspecies that lives in the hearts of dogs. Several human foods and household ingestibles are toxic to dogs, includingchocolate solids, causingtheobromine poisoning,onionsandgarlic, causingthiosulphate,sulfoxideordisulfidepoisoning,grapesandraisins,macadamia nuts, andxylitol.[34]The nicotine in tobacco can also be dangerous to dogs. Signs of ingestion can include copious vomiting (e.g., from eating cigar butts) ordiarrhea. Some other symptoms are abdominal pain, loss of coordination, collapse, or death.[35][pageneeded] Dogs are also vulnerable to some of the same health conditions as humans, includingdiabetes,dentalandheart disease,epilepsy,cancer,hypothyroidism, andarthritis. Lifespan Further information:Aging in dogs The typical lifespan of dogs varies widely among breeds, but for most, the median longevity (the age at which half the dogs in a population have died and half are still alive) ranges from 10 to 13 years.[36][37]The median longevity ofmixed-breed dogs, taken as an average of all sizes, is one or more years longer than that of purebred dogs when all breeds are averaged.[36][37][38]For dogs in England, increased body weight has been found to be negatively correlated with longevity (i.e., the heavier the dog, the shorter its lifespan), andmixed-breed dogslive on average 1.2 years longer thanpurebred dogs.[39] Reproduction Main article:Canine reproduction  A female dog nursing newborn puppies. In domestic dogs,sexual maturityhappens around six months to one year for both males and females, although this can be delayed until up to two years of age for some large breeds, and is the time at which female dogs will have their firstestrous cycle. They will experience subsequent estrous cycles semiannually, during which the body prepares forpregnancy. At the peak of the cycle, females will become estrous, mentally and physically receptive tocopulation. Because theovasurvive and can be fertilized for a week after ovulation, more than one male can sire the same litter.[12] Fertilization typically occurs two to five days after ovulation; 14–16 days after ovulation, the embryo attaches to the uterus and after seven to eight more days, a heartbeat is detectable.[40][41] Dogs bear their litters roughly 58 to 68 days afterfertilization,[12][42]with an average of 63 days, although the length of gestation can vary. An average litter consists of about sixpuppies.[43] Neutering Neuteringrefers to the sterilization of animals, usually byremoving the male's testiclesor the female'sovariesanduterus, to eliminate the ability to procreate and reducesex drive. Because ofdogs' overpopulationin some countries, many animal control agencies, such as theAmerican Society for the Prevention of Cruelty to Animals(ASPCA), advise that dogs not intended for further breeding should be neutered, so that they do not have undesired puppies that may later be euthanized.[44] According to theHumane Society of the United States, three to four million dogs and cats areeuthanizedeach year.[45]Many more are confined to cages in shelters because there are many more animals than there are homes. Spaying or castrating dogs helps keep overpopulation down.[46] Neutering reduces problems caused byhypersexuality, especially in male dogs.[47]Spayed female dogs are less likely to develop cancers affecting the mammary glands, ovaries, and other reproductive organs.[48][pageneeded]However, neutering increases the risk ofurinary incontinencein female dogs[49]andprostate cancerin males[50]andosteosarcoma,hemangiosarcoma,cruciate ligamentrupture, obesity, anddiabetes mellitusin either sex.[51] Inbreeding depression A common breeding practice for pet dogs is mating between close relatives (e.g., between half and full siblings).[52]Inbreeding depressionis considered to be due mainly to the expression of homozygous deleterious recessive mutations.[53]Outcrossing between unrelated individuals, including dogs of different breeds, results in the beneficial masking of deleterious recessive mutations in progeny.[54] In a study of seven dog breeds (theBernese Mountain Dog,Basset Hound,Cairn Terrier,Brittany,German Shepherd Dog,Leonberger, andWest Highland White Terrier), it was found that inbreeding decreases litter size and survival.[55]Another analysis of data on 42,855Dachshundlitters found that as theinbreeding coefficientincreased, litter size decreased and the percentage of stillborn puppies increased, thus indicating inbreeding depression.[56]In a study ofBoxerlitters, 22% of puppies died before reaching 7 weeks of age. Stillbirth was the most frequent cause of death, followed by infection. Mortality due to infection increased significantly with increases in inbreeding.[57] Behavior Main article:Dog behavior See also:Dog behavior §Behavior compared with other canids Dog behavior is the internally coordinated responses (actions or inactions) of the domestic dog (individuals or groups) to internal and external stimuli.[58]As the oldest domesticated species, dogs' minds inevitably have been shaped by millennia of contact with humans. As a result of this physical and social evolution, dogs have acquired the ability to understand and communicate with humans more than any other species and they are uniquely attuned to human behaviors.[13]Behavioral scientists have uncovered a surprising set of social-cognitive abilities in domestic dogs. These abilities are not possessed by the dog's closest canine relatives or other highly intelligent mammals, such asgreat apes, but rather parallel to children's social-cognitive skills.[59] Unlike other domestic species selected for production-related traits, dogs were initially selected for their behaviors.[60][61]In 2016, a study found that only 11 fixed genes showed variation between wolves and dogs. These gene variations were unlikely to have been the result of natural evolution and indicate selection on both morphology and behavior during dog domestication. These genes have been shown to affect thecatecholamine synthesispathway, with the majority of the genes affecting the fight-or-flight response[61][62](i.e., selection for tameness) and emotional processing.[61]Dogs generally show reduced fear and aggression compared with wolves.[61][63]Some of these genes have been associated with aggression in some dog breeds, indicating their importance in both the initial domestication and later in breed formation.[61]Traits of high sociability and lack of fear in dogs may include genetic modifications related toWilliams-Beuren syndromein humans, which causehypersociabilityat the expense of problem-solving ability.[64] Intelligence Main article:Dog intelligence Dog intelligence is the dog's ability to perceive information and retain it as knowledge for applying to solve problems. Studies of two dogs suggest that dogs can learn by inference and have advanced memory skills. A study withRico, aBorder Collie, showed that he knew the labels of over 200 different items. He inferred the names of novel things by exclusion learning and correctly retrieved those new items immediately and four weeks after the initial exposure. A study of another Border Collie, Chaser, documented his learning and memory capabilities. He had learned the names and could associate by verbal command over 1,000 words.[65]Dogs can read and react appropriately to human body language such as gesturing and pointing and human voice commands. One study of canine cognitive abilities found that dogs' capabilities are no more exceptional than those of other animals, such ashorses,chimpanzees, orcats.[66]One limited study of 18 household dogs found that they lacked spatial memory, and were more focussed on the "what" of a task rather than the "where".[67] Dogs demonstrate atheory of mindby engaging in deception.[68]An experimental study showed compelling evidence that Australiandingoscan outperform domestic dogs in non-social problem-solving, indicating that domestic dogs may have lost much of their original problem-solving abilities once they joined humans.[69]Another study revealed that after undergoing training to solve a simple manipulation task, dogs faced with an unsolvable version of the same problem look at the human, while socialized wolves do not.[70] Communication Main article:Dog communication  Dog sounds 0:15 A dog making noises and barking Problems playing this file? Seemedia help. Dog communication is how dogs convey information to other dogs, understand messages from humans and translate the information that dogs are transmitting.[71]: xii Communication behaviors of dogs include eye gaze, facial expression, vocalization, body posture (including movements of bodies and limbs), and gustatory communication (scents, pheromones, and taste). Humans communicate to dogs by using vocalization, hand signals, and body posture. Ecology Population The dog is probably the most widely abundant largecarnivoranliving in the human environment.[72][73]In 2013, the estimated global dog population was between 700 million[74]and 987 million.[75]About 20% of dogs live as pets in developed countries.[76]In the developing world, dogs are more commonly feral or communally owned, with pet dogs uncommon. Most of these dogs live their lives as scavengers and have never been owned by humans, with one study showing their most common response when approached by strangers is to run away (52%) or respond aggressively (11%).[77]Little is known about these dogs, or the dogs in developed countries that are feral, strays, or are in shelters because the great majority of modern research on dog cognition has focused on pet dogs living in human homes.[78] Competitors and predators Although dogs are the most abundant and widely distributed terrestrial carnivores, feral andfree-ranging dogs' potentialto compete with other large carnivores is limited by their strong association with humans.[72]For example, a review of the studies in dogs' competitive effects onsympatriccarnivores did not mention any research on competition between dogs and wolves.[79][80]Although wolves are known to kill dogs, they tend to live in pairs or in small packs in areas where they are highly persecuted, giving them a disadvantage facing large dog groups.[79][81] Wolves kill dogs wherever they are found together.[82]In some instances, wolves have displayed an uncharacteristic fearlessness of humans and buildings when attacking dogs to the extent that they have to be beaten off or killed.[83]Although the numbers of dogs killed each year are relatively low, it induces a fear of wolves entering villages and farmyards to take dogs and losses of dogs to wolves have led to demands for more liberal wolf hunting regulations.[79] Coyotesandbig catshave also been known to attack dogs. In particular,leopardsare known to have a preference for dogs and have been recorded to kill and consume them, no matter what their size.[84]Siberian tigersin theAmur Riverregion have killed dogs in the middle of villages. This indicates that the dogs were targeted. Amur tigers will not tolerate wolves as competitors within their territories, and the tigers could be considering dogs in the same way.[85]Striped hyenasare known to kill dogs in their range.[86] Diet See also:Dog food  AGolden Retrievergnawing on a pig's foot Dogs have been described asomnivores.[12][87][88]Compared to wolves, dogs from agricultural societies haveextra copies of amylaseand other genes involved in starch digestion that contribute to an increased ability to thrive on a starch-rich diet.[11]Similar to humans, some dog breeds produce amylase in theirsalivaand are classified as having a high starch diet.[89]However, more like cats and less like other omnivores, dogs can only producebile acidwithtaurineand they cannot producevitamin D, which they obtain from animal flesh. Also more like cats, dogs requirearginineto maintain its nitrogen balance. These nutritional requirements place dogs halfway between carnivores and omnivores.[90] Range As a domesticated or semi-domesticated animal, the dog is nearly universal among human societies. Notable exceptions once included: TheAboriginal Tasmanians, who were separated from Australia before the arrival ofdingoson that continent TheAndamanese peoples, who were isolated whenrising sea levelscovered the land bridge to Myanmar TheFuegians, who instead domesticated theFuegian dog, a different canid species Individual Pacific islands whose maritime settlers did not bring dogs, or where dogs died out after original settlement, notably theMariana Islands,[91]Palau[92]and most of theCaroline Islandswith exceptions such asFais IslandandNukuoro,[93]theMarshall Islands,[94]theGilbert Islands,[94]New Caledonia,[95]Vanuatu,[95][96]Tonga,[96]Marquesas,[96]Mangaiain theCook Islands,Rapa ItiinFrench Polynesia,Easter Island,[96]theChatham Islands[97]andPitcairn Island(settled by theBountymutineers, who killed off their dogs to escape discovery by passing ships).[98] Dogs were introduced toAntarcticaassled dogs, but were later outlawed by international agreement due to the possible risk of spreading infections.[99] Roles with humans Domestic dogs inherited complex behaviors, such asbite inhibition, from their wolf ancestors, which would have beenpack hunterswith a complex body language. These sophisticated forms of social cognition and communication may account for their trainability, playfulness and ability to fit into human households and social situations. These attributes have given dogs a relationship with humans that has enabled them to become one of the most successful animals today.[100] The dogs' value to early human hunter-gatherers led to them quickly becoming ubiquitous across world cultures. Dogs perform many roles for people, such ashunting,herding,pulling loads,protection,assisting policeand themilitary,companionshipandaiding disabled individuals. This influence on human society has given them the nickname "man's best friend" in the Western world. In some cultures, however, dogsare also a source of meat.[101][102] Pets  Siberian Huskiesarepack animalsthat still enjoy some human companionship It is estimated that three-quarters of the world's dog population lives in the developing world as feral, village, or community dogs, with pet dogs uncommon.[103][pageneeded] "The most widespread form of interspecies bonding occurs between humans and dogs"[104]and the keeping of dogs as companions, particularly by elites, has a long history.[14]Pet dog populations grew significantly afterWorld War IIas suburbanization increased.[14]In the 1950s and 1960s, dogs were kept outside more often than they tend to be today[105](the expression "in the doghouse" - recorded since 1932[106]- to describe exclusion from the group implies a distance between thedoghouseand the home) and were still primarily functional, acting as a guard, children's playmate, or walking companion. From the 1980s, there have been changes in the pet dog's role, such as the increased role of dogs in the emotional support of their human guardians.[107][pageneeded]People and their dogs have become increasingly integrated and implicated in each other's lives[108][pageneeded]to the point where pet dogs actively shape how a family and home are experienced.[109] There have been two significant trends occurring within the second half of the 20th century in pet dogs' changing status. The first has been"commodification", shaping it to conform to social expectations of personality and behavior.[109]The second has been the broadening of the family's concept and the home to include dogs-as-dogs within everyday routines and practices.[109] A vast range of commodity forms aims to transform a pet dog into an ideal companion.[110]The list of goods, services, and places available is enormous: from dog perfumes, couture, furniture and housing to dog groomers, therapists, trainers and caretakers, dog cafes, spas, parks and beaches and dog hotels, airlines and cemeteries.[110]Dog training books, classes, and television programs proliferated as the process of commodifying the pet dog continued.[111] The majority of contemporary dog owners describe their pet as part of the family, although some ambivalence about the relationship is evident in the popular reconceptualization of the dog-human family as a pack.[109]Some dog trainers, such as on the television programDog Whisperer, have promoted adominance modelof dog-human relationships. However, it has been disputed that "trying to achieve status" is characteristic of dog-human interactions.[112]The idea of the "alpha dog" trying to be dominant is based on a disproved theory about wolf packs.[113][114]Pet dogs play an active role in family life; for example, a study of conversations in dog-human families showed how family members use the dog as a resource, talking to the dog, or talking through the dog; to mediate their interactions with each other.[115] Increasingly, human family-members engage in activities centered on the dog's perceived needs and interests, or in which the dog is an integral partner, such asdog dancinganddog yoga.[110] According to statistics published by theAmerican Pet Products Manufacturers Associationin the National Pet Owner Survey in 2009–2010, an estimated 77.5million people in the United States have pet dogs.[116]The same source shows that nearly 40% of American households own at least one dog, of which 67% own just one dog, 25% two dogs and nearly 9% more than two dogs. There does not seem to be anygender preferenceamong dogs as pets, as the statistical data reveal an equal number of male and female pet dogs. Although several programs promotepet adoption, less than one-fifth of the owned dogs come fromshelters.[116] A study usingmagnetic resonance imaging(MRI) to compare humans and dogs showed that dogs have the same response to voices and use the same parts of the brain as humans do. This gives dogs the ability to recognize human emotional sounds, making them friendly social pets to humans.[117] Workers Dogs have lived and worked with humans in many roles. In addition to dogs' role as companion animals, dogs have been bred for herding livestock (collies,sheepdogs),[118][pageneeded][12]hunting (hounds, pointers)[119][pageneeded]and rodent control (terriers).[12]Other types ofworking dogsincludesearch and rescue dogs,[120]detection dogstrained to detectillicit drugs[121]orchemical weapons;[122]guard dogs; dogs who assist fishermen with the use of nets; and dogs that pull loads.[12]In 1957, the dogLaikabecame the first animal to be launched intoEarth orbit, aboard theSoviets'Sputnik 2; she died during the flight.[123][124] Various kinds ofservice dogsandassistance dogs, includingguide dogs,hearing dogs,mobility assistance dogsandpsychiatric service dogs, assist individuals with disabilities.[125][126]Some dogs owned by people with epilepsy have been shown to alert their handler when the handler shows signs of an impending seizure, sometimes well in advance of onset, allowing the guardian to seek safety, medication, or medical care.[127] Athletes and models See also:Conformation show People often enter their dogs in competitions, such as breed-conformation shows orsports, including racing, sledding and agility competitions. In conformation shows, also referred to as breed shows, a judge familiar with the specific dog breed evaluates individual purebred dogs for conformity with their established breed type as described in the breed standard. As the breed standard only deals with the dog's externally observable qualities (such as appearance, movement and temperament), separately tested qualities (such as ability or health) are not part of the judging in conformation shows. Food Main article:Dog meat Dog meat is consumed in someEast Asiancountries, includingKorea,[128][pageneeded]China,[101]Vietnam[102]and thePhilippines,[129]which dates back to antiquity.[130]Based on limited data, it is estimated that 13–16million dogs are killed and consumed in Asia every year.[131]In China, debates have ensued over banning the consumption of dog meat.[132]Following the Sui and Tang dynasties of the first millennium, however, people living on northern China's plains began to eschew eating dogs, which is likely due to Buddhism and Islam's spread, two religions that forbade the consumption of certain animals, including the dog. As members of the upper classes shunned dog meat, it gradually became a social taboo to eat it, even though the general population continued to consume it for centuries afterward.[133]Dog meat is also consumed in some parts of Switzerland.[134]Other cultures, such asPolynesiaandpre-Columbian Mexico, also consumed dog meat in their history. Dog fat is also reportedly believed to be beneficial for the lungs in some parts of Poland[135][136]and Central Asia.[137][138]Proponents of eating dog meat have argued that placing a distinction between livestock and dogs is Western hypocrisy and that there is no difference in eating different animals' meat.[139][140][141][142] In Korea, the primary dog breed raised for meat, theNureongi, differs from those breeds raised for pets that Koreans may keep in their homes.[143] The most popular Korean dog dish is calledbosintang, a spicy stew meant to balance the body's heat during the summer months. Followers of the custom claim this is done to ensure good health by balancing one'sgi, or the body's vital energy. A 19th-century version of bosintang explains that the dish is prepared by boiling dog meat withscallionsand chili powder. Variations of the dish contain chicken and bamboo shoots. While the dishes are still prevalent in Korea with a segment of the population, dog is not as widely consumed as beef, pork and chicken.[143] Health risks Further information:Dog bite,Canine vector-borne disease, andDog bite prevention In 2018, theWHOreported that 59,000 people died globally fromrabies, with 59.6% in Asia and 36.4% in Africa. Rabies is a disease for which dogs are the most important vector.[144]Significant dog bites affect tens of millions of people globally each year. Children in mid-to-late childhood are the largest percentage bitten by dogs, with a greater risk of injury to the head and neck. They are more likely to need medical treatment and have the highest death rate.[145]Sharp claws with powerful muscles behind them can lacerate flesh in a scratch that can lead to serious infections.[146] In theU.S.,catsand dogs are a factor in more than 86,000 falls each year.[147]It has been estimated that around 2% of dog-related injuries treated in U.K. hospitals are domestic accidents. The same study found that while dog involvement in road traffic accidents was difficult to quantify, dog-associated road accidents involving injury more commonly involved two-wheeled vehicles.[148] Toxocara canis(dogroundworm) eggs in dog feces can causetoxocariasis. In the United States, about 10,000 cases ofToxocarainfection are reported in humans each year, and almost 14% of the U.S. population is infected.[149]Untreated toxocariasis can cause retinal damage and decreased vision.[150]Dog feces can also containhookwormsthat causecutaneous larva migransin humans.[151][152] Health benefits  Walking a dog Dogs suffer from the same common disorders as humans; these include cancer, diabetes, heart disease and neurologic disorders. Their pathology is similar to humans, as is their response to treatment and their outcomes. Researchers are identifying the genes associated with dog diseases similar to human disorders, but lack mouse models to find cures for both dogs and humans. The genes involved in canine obsessive-compulsive disorders led to the detection of four genes in humans' related pathways.[10] The scientific evidence is mixed as to whether a dog's companionship can enhance human physical health and psychological well-being.[153]Studies suggesting that there are benefits to physical health and psychological well-being[154]have been criticized for being poorly controlled.[155]It found that "the health of elderly people is related to their health habits and social supports but not to their ownership of, or attachment to, a companion animal." Earlier studies have shown that people who keep pet dogs or cats exhibit better mental and physical health than those who do not, making fewer visits to the doctor and being less likely to be on medication than non-guardians.[156] A 2005 paper states "recent research has failed to support earlier findings that pet ownership is associated with a reduced risk of cardiovascular disease, a reduced use of general practitioner services, or any psychological or physical benefits on health for community dwelling older people. Research has, however, pointed to significantly less absenteeism from school through sickness among children who live with pets."[153]In one study, new guardians reported a highly significant reduction in minor health problems during the first month following pet acquisition. This effect was sustained in those with dogs through to the end of the study.[157] People with pet dogs took considerably more physical exercise than those with cats and those without pets. The results provide evidence that keeping pets may have positive effects on human health and behavior and that for guardians of dogs, these effects are relatively long-term.[157]Pet guardianship has also been associated with increased coronary artery disease survival. Human guardians are significantly less likely to die within one year of an acute myocardial infarction than those who did not own dogs.[158]The association between dog ownership and adult physical activity levels has been reviewed by several authors.[159][160] The health benefits of dogs can result from contact with dogs in general, not solely from having dogs as pets. For example, when in a pet dog's presence, people show reductions in cardiovascular, behavioral and psychological indicators of anxiety.[161]Other health benefits are gained from exposure to immune-stimulating microorganisms, which can protect against allergies and autoimmune diseases according to thehygiene hypothesis. The benefits of contact with a dog also include social support, as dogs cannot only provide companionship and social support themselves but also act as facilitators of social interactions between humans.[162]One study indicated that wheelchair users experience more positive social interactions with strangers when accompanied by a dog than when they are not.[163]In 2015, a study found that pet owners were significantly more likely to get to know people in their neighborhood than non-pet owners.[164] Using dogs and other animals as a part of therapy dates back to the late 18th century, when animals were introduced into mental institutions to help socialize patients with mental disorders.[165]Animal-assisted intervention research has shown that animal-assisted therapy with a dog can increase social behaviors, such as smiling and laughing, among people with Alzheimer's disease.[166]One study demonstrated that children with ADHD and conduct disorders who participated in an education program with dogs and other animals showed increased attendance, increased knowledge and skill objectives and decreased antisocial and violent behavior compared with those not in an animal-assisted program.[167] Cultural importance Main articles:Cultural depictions of dogsandDogs in religion Further information:List of fictional dogs  Cerberus, with the gluttons inDante'sThird Circle of Hell.William Blake. Dogs were depicted to symbolizeguidance,protection,loyalty,fidelity,faithfulness,alertness, andlove.[168]In ancientMesopotamia, from theOld Babylonian perioduntil theNeo-Babylonian, dogs were the symbol ofNinisina, the goddess of healing and medicine,[169]and her worshippers frequently dedicated small models of seated dogs to her.[169]In theNeo-Assyrianand Neo-Babylonian periods, dogs were used as emblems of magical protection.[169]InChina,KoreaandJapan, dogs are viewed as kind protectors.[170] In mythology, dogs often serve as pets or as watchdogs.[170]Stories of dogs guarding the gates of the underworld recur throughout Indo-European mythologies[171][172]and may originate fromProto-Indo-European religion.[171][172]InGreek mythology,Cerberusis a three-headed,dragon-tailed watchdog who guards the gates ofHades.[170]Dogs are also associated with the Greek goddessHecate.[173]InNorse mythology, a bloody, four-eyed dog calledGarmrguardsHelheim.[170]InPersian mythology, two four-eyed dogs guard theChinvat Bridge.[170]InWelsh mythology,Annwnis guarded byCŵn Annwn.[170]InHindu mythology,Yama, the god of death, owns two watchdogs who have four eyes. They are said to watch over the gates ofNaraka.[174]A black dog is also considered to be thevahana(vehicle) ofBhairava(an incarnation of Shiva).[175] InChristianity, dogs represent faithfulness.[170]Within theRoman Catholicdenomination specifically, the iconography ofSaint Dominicincludes a dog, after the hallow's mother dreamt of a dog springing from her womb and becoming pregnant shortly after that.[176]As such, theDominican Order(Ecclesiastical Latin:Domini canis) means "dog of the Lord" or "hound of the Lord" (Ecclesiastical Latin:Domini canis).[176]In Christian folklore, achurch grimoften takes the form of a black dog to guard Christian churches and theirchurchyardsfromsacrilege.[177]Jewish lawdoes not prohibit keeping dogs and other pets.[178]Jewish law requires Jews to feed dogs (and other animals that they own) before themselves and make arrangements for feeding them before obtaining them.[178]The view on dogs inIslamis mixed, with some schools of thought viewing it as unclean,[170]althoughKhaled Abou El Fadlstates that this view is based on "pre-Islamic Arab mythology" and "a tradition to be falsely attributed to the Prophet."[179]Therefore, Sunni Malaki and Hanafi jurists permit the trade of and keeping of dogs as pets.[180]

Thegoatordomestic goat(Capra hircus) is adomesticatedspecies ofgoat-antelopetypically kept aslivestock. It wasdomesticatedfrom thewild goat(C. aegagrus) ofSouthwest AsiaandEastern Europe. The goat is a member of the animal familyBovidaeand the tribeCaprini, meaning it is closely related to thesheep. There are over 300 distinctbreedsof goat.[1]It is one of the oldest domesticated species of animal, according to archaeological evidence that its earliest domestication occurred in Iran at 10,000 calibrated calendar years ago. Domestic goat Temporal range:0.01–0Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓ Neolithic–Recent Apygmy goaton atree stump Conservation status Domesticated Scientific classificationKingdom:AnimaliaPhylum:ChordataClass:MammaliaOrder:ArtiodactylaFamily:BovidaeSubfamily:CaprinaeTribe:CapriniGenus:CapraSpecies: C.hircus Binomial nameCapra hircus Linnaeus,1758 Synonyms Capra aegagrus hircusLinnaeus,1758 Capra depressaLinnaeus,1758 Capra mambricaLinnaeus,1758 Capra reversaLinnaeus,1758 Goat-herding is an ancient tradition that is still important in places such as Egypt. Goats have been used formilk,meat,fur, andskinsacross much of the world.[3]Milk from goats is often turned intogoat cheese. Female goats are referred to asdoesornannies,intactmales are calledbucksorbillies, and juvenile goats of both sexes are calledkids.Castratedmales are calledwethers. While the wordshircineandcaprineboth refer to anything having a goat-like quality,hircineis used most often to emphasize the distinct smell of domestic goats. In 2011, there were more than 924 million goats living in the world, according to theUNFood and Agriculture Organization.

Thegoatordomestic goat(Capra hircus) is adomesticatedspecies ofgoat-antelopetypically kept aslivestock. It wasdomesticatedfrom thewild goat(C. aegagrus) ofSouthwest AsiaandEastern Europe. The goat is a member of the animal familyBovidaeand the tribeCaprini, meaning it is closely related to thesheep. There are over 300 distinctbreedsof goat.[1]It is one of the oldest domesticated species of animal, according to archaeological evidence that its earliest domestication occurred in Iran at 10,000 calibrated calendar years ago. Domestic goat Temporal range:0.01–0Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓ Neolithic–Recent Apygmy goaton atree stump Conservation status Domesticated Scientific classificationKingdom:AnimaliaPhylum:ChordataClass:MammaliaOrder:ArtiodactylaFamily:BovidaeSubfamily:CaprinaeTribe:CapriniGenus:CapraSpecies: C.hircus Binomial nameCapra hircus Linnaeus,1758 Synonyms Capra aegagrus hircusLinnaeus,1758 Capra depressaLinnaeus,1758 Capra mambricaLinnaeus,1758 Capra reversaLinnaeus,1758 Goat-herding is an ancient tradition that is still important in places such as Egypt. Goats have been used formilk,meat,fur, andskinsacross much of the world.[3]Milk from goats is often turned intogoat cheese. Female goats are referred to asdoesornannies,intactmales are calledbucksorbillies, and juvenile goats of both sexes are calledkids.Castratedmales are calledwethers. While the wordshircineandcaprineboth refer to anything having a goat-like quality,hircineis used most often to emphasize the distinct smell of domestic goats. In 2011, there were more than 924 million goats living in the world, according to theUNFood and Agriculture Organization.

This article is about the species that is commonly kept as a pet. For the cat family, seeFelidae. For other uses, seeCat (disambiguation). "Cats" redirects here. For other uses, seeCats (disambiguation). Thecat(Felis catus) is adomesticspeciesof smallcarnivorousmammal.[1][2]It is the only domesticated species in the familyFelidaeand is often referred to as thedomestic catto distinguish it from the wild members of the family.[4]A cat can either be ahouse cat, afarm cator aferal cat; the latter ranges freely and avoids human contact.[5]Domestic cats are valued by humans for companionship and their ability to killrodents. About 60cat breedsare recognized by variouscat registries.[6] Cat Temporal range: 9,500 years ago – present Various types of cat Conservation status Domesticated Scientific classificationKingdom:AnimaliaPhylum:ChordataClass:MammaliaOrder:CarnivoraSuborder:FeliformiaFamily:FelidaeSubfamily:FelinaeGenus:FelisSpecies: F.catus[1] Binomial nameFelis catus[1] Linnaeus,1758[2] Synonyms Catus domesticusErxleben, 1777[3] F. angorensisGmelin, 1788 F. vulgarisFischer, 1829 The cat is similar inanatomyto the other felid species: it has a strong flexible body, quickreflexes, sharp teeth andretractable clawsadapted to killing small prey. Itsnight visionand sense of smell are well developed.Cat communicationincludesvocalizationslikemeowing,purring, trilling, hissing,growlingand grunting as well ascat-specific body language. Apredatorthat is most active at dawn and dusk (crepuscular), the cat is a solitary hunter but asocial species. It can hear sounds too faint or too high infrequencyfor human ears, such as those made bymiceand other small mammals.[7]Cats also secrete and perceivepheromones.[8] Female domestic cats can have kittens from spring to late autumn, with litter sizes often ranging from two to five kittens.[9]Domestic cats are bred and shown at events as registeredpedigreed cats, a hobby known ascat fancy.Population controlof cats may be effected byspayingandneutering, but their proliferation and the abandonment of pets has resulted in large numbers of feral cats worldwide, contributing to the extinction of entire bird, mammal, and reptile species.[10] It was long thought that cat domestication began inancient Egypt, wherecats were veneratedfrom around 3100 BC,[11][12]but recent advances in archaeology and genetics have shown that their domestication occurred inWestern Asiaaround 7500 BC.[13] As of 2021,there were an estimated 220 million owned and 480 million stray cats in the world.[14][15]As of 2017,the domestic cat was the second most popular pet in the United States, with 95.6 million cats owned[16][17][18]and around 42 million households own at least one cat.[19]In the United Kingdom, 26% of adults have a cat with an estimated population of 10.9 million pet cats as of 2020.[20] Contents Etymology and naming The origin of the English wordcat,Old Englishcatt, is thought to be theLate Latinwordcattus, which was first used at the beginning of the 6th century.[21]It was suggested that the word 'cattus' is derived from anEgyptianprecursor ofCopticϣⲁⲩšau, "tomcat", or its feminine form suffixed with-t.[22]The Late Latin word may be derived from anotherAfro-Asiatic[23]orNilo-Saharanlanguage. TheNubianwordkaddîska"wildcat" andNobiinkadīsare possible sources or cognates.[24]The Nubian word may be a loan fromArabicقَطّ‎qaṭṭ~قِطّqiṭṭ. It is "equally likely that the forms might derive from an ancient Germanic word, imported into Latin and thence to Greek and to Syriac and Arabic".[25]The word may be derived from Germanic and Northern European languages, and ultimately be borrowed fromUralic, cf.Northern Samigáđfi, "femalestoat", andHungarianhölgy, "lady, female stoat"; fromProto-Uralic*käďwä, "female (of a furred animal)".[26] The Englishpuss, extended aspussyandpussycat, is attested from the 16th century and may have been introduced fromDutchpoesor fromLow Germanpuuskatte, related toSwedishkattepus, orNorwegianpus,pusekatt. Similar forms exist in LithuanianpuižėandIrishpuisínorpuiscín. The etymology of this word is unknown, but it may have simplyarisen from a soundused to attract a cat.[27][28] A male cat is called atomortomcat[29](or agib,[30]if neutered). Anunspayedfemale is called aqueen,[31](or amolly,[32]if spayed), especially in a cat-breeding context. A juvenile cat is referred to as akitten. InEarly Modern English, the wordkittenwas interchangeable with the now-obsolete wordcatling.[33]A group of cats can be referred to as aclowderor aglaring.[34] Taxonomy Thescientific nameFelis catuswas proposed byCarl Linnaeusin 1758 for a domestic cat.[1][2]Felis catus domesticuswas proposed byJohann Christian Polycarp Erxlebenin 1777.[3]Felis daemonproposed byKonstantin Alekseevich Satuninin 1904 was a black cat from theTranscaucasus, later identified as a domestic cat.[35][36] In 2003, theInternational Commission on Zoological Nomenclatureruled that the domestic cat is a distinct species, namelyFelis catus.[37][38]In 2007, it was considered asubspecies,F. silvestris catus, of theEuropean wildcat(F. silvestris) following results ofphylogeneticresearch.[39][40]In 2017, the IUCN Cat Classification Taskforce followed the recommendation of the ICZN in regarding the domestic cat as a distinct species,Felis catus.[41] Evolution Main article:Cat evolution  Skulls of a wildcat (top left), a housecat (top right), and a hybrid between the two. (bottom center) The domestic cat is a member of the Felidae, afamilythat had acommon ancestorabout 10–15 million years ago.[42]ThegenusFelisdivergedfrom other Felidae around 6–7 million years ago.[43]Results ofphylogeneticresearch confirm that the wildFelisspecies evolved throughsympatricorparapatric speciation, whereas the domestic cat evolved throughartificial selection.[44]The domesticated cat and its closest wild ancestor arediploidand both possess 38chromosomes[45]and roughly 20,000 genes.[46]Theleopard cat(Prionailurus bengalensis) wastamedindependently in China around 5500 BC. This line of partially domesticated cats leaves no trace in the domestic cat populations of today.[47] Domestication See also:Evolution of the domesticated cat  A cat eating a fish under a chair, amuralin an Egyptian tomb dating to the 15th century BC The earliest known indication for thetamingof anAfrican wildcat(F. lybica) wasexcavatedclose by a humanNeolithicgrave inShillourokambos, southernCyprus, dating to about 7500–7200 BC. Since there is no evidence of native mammalianfaunaon Cyprus, the inhabitants of this Neolithic village most likely brought the cat and other wild mammals to the island from theMiddle Easternmainland.[48]Scientists therefore assume that African wildcats were attracted to early human settlements in theFertile Crescentby rodents, in particular thehouse mouse(Mus musculus), and were tamed by Neolithic farmers. Thismutualrelationship between early farmers and tamed cats lasted thousands of years. Asagricultural practicesspread, so did tame and domesticated cats.[13][6]Wildcats of Egypt contributed to the maternalgene poolof the domestic cat at a later time.[49] The earliest known evidence for the occurrence of the domestic cat inGreecedates to around 1200 BC. Greek,Phoenician,CarthaginianandEtruscantraders introduced domestic cats to southern Europe.[50]During theRoman Empirethey were introduced toCorsicaandSardiniabefore the beginning of the 1st millennium.[51]By the 5th century BC, they were familiar animals around settlements inMagna GraeciaandEtruria.[52]By the end of the Roman Empire in the 5th century, the Egyptian domestic cat lineage had arrived in aBaltic Seaport in northernGermany.[49] During domestication, cats have undergone only minor changes in anatomy and behavior, and they are still capable of surviving in the wild. Several natural behaviors and characteristics of wildcats may havepre-adaptedthem for domestication as pets. These traits include their small size, social nature, obvious body language, love of play and relatively high intelligence. CaptiveLeoparduscats may also display affectionate behavior toward humans but were not domesticated.[53]House cats often mate with feral cats,[54]producing hybrids such as theKellas catinScotland.[55]Hybridisation between domestic and other Felinae speciesis also possible.[56] Development ofcat breedsstarted in the mid 19th century.[57]An analysis of the domestic catgenomerevealed that the ancestral wildcat genome was significantly altered in the process of domestication, as specificmutationswere selected to develop cat breeds.[58]Most breeds are founded on random-bred domestic cats.Genetic diversityof these breeds varies between regions, and is lowest in purebred populations, which show more than 20 deleteriousgenetic disorders.[59] Characteristics Main article:Cat anatomy Size  Diagram of the generalanatomyof a male domestic cat The domestic cat has a smallerskulland shorter bones than theEuropean wildcat.[60]It averages about 46cm (18in) in head-to-body length and 23–25cm (9–10in) in height, with about 30cm (12in) long tails. Males are larger than females.[61]Adult domestic cats typically weigh between 4 and 5kg (9 and 11lb).[44] Skeleton Cats have sevencervical vertebrae(as do mostmammals); 13thoracic vertebrae(humans have 12); sevenlumbar vertebrae(humans have five); threesacral vertebrae(as do most mammals, but humans have five); and a variable number ofcaudal vertebraein the tail (humans have only three to five vestigial caudal vertebrae, fused into an internalcoccyx).[62]: 11 The extra lumbar and thoracic vertebrae account for the cat's spinal mobility and flexibility. Attached to the spine are 13 ribs, the shoulder, and thepelvis.[62]: 16 Unlike human arms, cat forelimbs are attached to the shoulder by free-floatingclaviclebones which allow them to pass their body through any space into which they can fit their head.[63] Skull  Cat skull  A cat with its mouth open exposing its teeth The cat skull is unusual among mammals in having very largeeye socketsand a powerful specialized jaw.[64]: 35 Within the jaw, cats have teeth adapted for killing prey and tearing meat. When it overpowers its prey, a cat delivers a lethal neck bite with its two longcanine teeth, inserting them between two of the prey'svertebraeand severing itsspinal cord, causing irreversibleparalysisand death.[65]Compared to other felines, domestic cats have narrowly spaced canine teeth relative to the size of their jaw, which is an adaptation to their preferred prey of small rodents, which have small vertebrae.[65]Thepremolarand firstmolartogether compose thecarnassialpair on each side of the mouth, which efficiently shears meat into small pieces, like a pair of scissors. These are vital in feeding, since cats' smallmolarscannot chew food effectively, and cats are largely incapable of mastication.[64]: 37 Although cats tend to have better teeth than most humans, with decay generally less likely because of a thicker protective layer of enamel, a less damaging saliva, less retention of food particles between teeth, and a diet mostly devoid of sugar, they are nonetheless subject to occasional tooth loss and infection.[66] Claws  Shed claw sheaths Cats have protractible and retractable claws.[67]In their normal, relaxed position, the claws are sheathed with the skin and fur around the paw's toe pads. This keeps the claws sharp by preventing wear from contact with the ground and allows for the silent stalking of prey. The claws on the forefeet are typically sharper than those on the hindfeet.[68]Cats can voluntarily extend their claws on one or more paws. They may extend their claws in hunting or self-defense, climbing,kneading, or for extra traction on soft surfaces. Cats shed the outside layer of their claw sheaths when scratching rough surfaces.[69] Most cats have five claws on their front paws and four on their rear paws. Thedewclawisproximalto the other claws. More proximally is a protrusion which appears to be a sixth "finger". This special feature of the front paws on the inside of the wrists has no function in normal walking but is thought to be an antiskidding device used while jumping. Some cat breeds are prone to having extra digits ("polydactyly").[70]Polydactylous cats occur along North America's northeast coast and in Great Britain.[71] Ambulation The cat isdigitigrade. It walks on the toes, with the bones of the feet making up the lower part of the visible leg.[72]Unlike most mammals, it uses a "pacing"gaitand moves both legs on one side of the body before the legs on the other side. It registers directly by placing each hind paw close to the track of the corresponding fore paw, minimizing noise and visible tracks. This also provides sure footing for hind paws when navigating rough terrain. As it speeds up from walking to trotting, its gait changes to a "diagonal" gait: The diagonally opposite hind and fore legs move simultaneously.[73] Balance 13:37 Comparison of cat righting reflexes ingravityand zero gravity Most breeds of cat are noted fond of sitting in high places, orperching. A higher place may serve as a concealed site from which to hunt; domestic cats strike prey by pouncing from a perch such as a tree branch. Another possible explanation is that height gives the cat a better observation point, allowing it to survey its territory. A cat falling from heights of up to 3 meters (9.8ft) can right itself and land on its paws.[74] During a fall from a high place, a cat reflexively twists its body and rights itself to land on its feet using its acute sense of balance and flexibility. This reflex is known as thecat righting reflex.[75]A cat always rights itself in the same way during a fall, if it has enough time to do so, which is the case in falls of 90cm (2ft 11in) or more.[76]How cats are able to right themselves when falling has been investigated as the "falling cat problem". Senses Main article:Cat senses Vision  Reflection of camera flash from thetapetum lucidum Cats have excellentnight visionand can see at only one-sixth the light level required for human vision.[64]: 43 This is partly the result of cat eyes having atapetum lucidum, which reflects any light that passes through theretinaback into the eye, thereby increasing the eye's sensitivity to dim light.[77]Large pupils are an adaptation to dim light. The domestic cat hasslit pupils, which allow it to focus bright light withoutchromatic aberration.[78]At low light, a cat's pupils expand to cover most of the exposed surface of its eyes.[79]The domestic cat has rather poorcolor visionand only two types ofcone cells, optimized for sensitivity to blue and yellowish green; its ability to distinguish between red and green is limited.[80]A response to middle wavelengths from a system other than therod cellsmight be due to a third type of cone. This appears to be an adaptation to low light levels rather than representing truetrichromaticvision.[81] Hearing The domestic cat's hearing is most acute in the range of 500Hz to 32kHz.[82]It can detect an extremely broad range of frequencies ranging from 55Hz to 79,000Hz. It can hear a range of 10.5octaves, while humans and dogs can hear ranges of about 9 octaves.[83][84]Its hearing sensitivity is enhanced by its large movable outer ears, thepinnae, which amplify sounds and help detect the location of a noise. It can detectultrasound, which enables it to detect ultrasonic calls made byrodentprey.[85][86]Recent research has shown that cats have socio-spatial cognitive abilities to create mental maps of owners' locations based on hearing owners' voices.[87] Smell Cats have an acute sense of smell, due in part to their well-developedolfactory bulband a large surface ofolfactory mucosa, about5.8 square centimetres (29⁄32square inch) in area, which is about twice that of humans.[88]Cats and many other animals have aJacobson's organin their mouths that is used in the behavioral process offlehmening. It allows them to sense certain aromas in a way that humans cannot. Cats are sensitive topheromonessuch as3-mercapto-3-methylbutan-1-ol,[89]which they use to communicate throughurine sprayingand marking withscent glands.[90]Many cats also respond strongly to plants that containnepetalactone, especiallycatnip, as they can detect that substance at less than one part per billion.[91]About 70–80% of cats are affected by nepetalactone.[92]This response is also produced by other plants, such as silver vine (Actinidia polygama) and the herbvalerian; it may be caused by the smell of these plants mimicking a pheromone and stimulating cats' social or sexual behaviors.[93] Taste Cats have relatively fewtaste budscompared to humans (470 or so versus more than 9,000 on the human tongue).[94]Domestic and wild cats share ataste receptor gene mutationthat keeps their sweet taste buds from binding to sugary molecules, leaving them with no ability to tastesweetness.[95]Their taste buds instead respond toacids,amino acidslike protein, and bitter tastes.[96]Cats also have a distinct temperature preference for their food, preferring food with a temperature around 38°C (100°F) which is similar to that of a fresh kill and routinely rejecting food presented cold or refrigerated (which would signal to the cat that the "prey" item is long dead and therefore possibly toxic or decomposing).[94] Whiskers  The whiskers of a cat are highly sensitive to touch To aid with navigation and sensation, cats have dozens of movablewhiskers (vibrissae)over their body, especially their faces. These provide information on the width of gaps and on the location of objects in the dark, both by touching objects directly and by sensing air currents; they also trigger protectiveblink reflexesto protect the eyes from damage.[64]: 47  Behavior See also:Cat behavior  Cat lying onrice straw Outdoor cats are active both day and night, although they tend to be slightly more active at night.[97]Domestic cats spend the majority of their time in the vicinity of their homes but can range many hundreds of meters from this central point. They establishterritoriesthat vary considerably in size, in one study ranging from 7to 28 hectares (17–69 acres).[98]The timing of cats' activity is quite flexible and varied, which means house cats may be moreactive in the morning and evening, as a response to greater human activity at these times.[99] Cats conserve energy by sleeping more than most animals, especially as they grow older. The daily duration of sleep varies, usually between 12 and 16 hours, with 13 and 14 being the average. Some cats can sleep as much as 20 hours. The term "cat nap" for a short rest refers to the cat's tendency to fall asleep (lightly) for a brief period. While asleep, cats experience short periods ofrapid eye movement sleepoften accompanied by muscle twitches, which suggests they are dreaming.[100] Sociability The social behavior of the domestic cat ranges from widely dispersed individuals toferal cat coloniesthat gather around a food source, based on groups of co-operating females.[101][102]Within such groups, one cat is usually dominant over the others.[103]Each cat in a colony holds a distinct territory, with sexually active males having the largest territories, which are about 10 times larger than those of female cats and may overlap with several females' territories. These territories are marked byurine spraying, by rubbing objects at head height with secretions from facial glands, and bydefecation.[90]Between these territories are neutral areas where cats watch and greet one another without territorial conflicts. Outside these neutral areas, territory holders usually chase away stranger cats, at first by staring, hissing, andgrowlingand, if that does not work, by short but noisy and violent attacks. Despite this colonial organization, cats do not have a social survival strategy or apack mentality, and always hunt alone.[104] Life in proximity to humans and other domestic animals has led to a symbiotic social adaptation in cats, and cats may express great affection toward humans or other animals.Ethologically, a cat's human keeper functions as if a mother surrogate.[105]Adult cats live their lives in a kind of extended kittenhood, a form of behavioralneoteny. Their high-pitched sounds may mimic the cries of a hungry human infant, making them particularly difficult for humans to ignore.[106]Some pet cats are poorly socialized. In particular, older cats show aggressiveness toward newly arrived kittens, which include biting and scratching; this type of behavior is known as feline asocial aggression.[107] Redirected aggressionis a common form of aggression which can occur in multiple cat households. In redirected aggression there is usually something that agitates the cat: this could be a sight, sound, or another source of stimuli which causes a heightened level of anxiety or arousal. If the cat cannot attack the stimuli, it may direct anger elsewhere by attacking or directing aggression to the nearest cat, dog, human or other being.[108][109] Domestic cats'scent rubbingbehavior toward humans or other cats is thought to be a feline means for social bonding.[110] Communication Main article:Cat communication  Vocalizing domestic cat Domestic cats use manyvocalizationsfor communication, includingpurring,trilling, hissing, growling/snarling, grunting, and several different forms of meowing.[7]Theirbody language, including position of ears and tail, relaxation of the whole body, and kneading of the paws, are all indicators of mood. The tail and ears are particularly important social signal mechanisms in cats. A raised tail indicates a friendly greeting, and flattened ears indicates hostility. Tail-raising also indicates the cat's position in the group'ssocial hierarchy, with dominant individuals raising their tails less often than subordinate ones.[111]Feral cats are generally silent.[112]: 208 Nose-to-nose touching is also a common greeting and may be followed bysocial grooming, which is solicited by one of the cats raising and tilting its head.[102] Purringmay have developed as an evolutionary advantage as a signaling mechanism of reassurance between mother cats andnursingkittens, who are thought to use it as a care-soliciting signal.[113]Post-nursing cats also often purr as a sign of contentment: when being petted, becoming relaxed,[114][115]or eating. Even though purring as popularly interpreted as indicative of pleasure, it has been recorded in a wide variety of circumstances, most of which involve physical contact between the cat and another, presumably trusted individual.[113]Some cats have been observed to purr continuously when chronically ill or in apparent pain.[116] The exact mechanism by which cats purr has long been elusive, but it has been proposed that purring is generated via a series of sudden build-ups and releases of pressure as theglottisis opened and closed, which causes thevocal foldsto separate forcefully. The laryngeal muscles in control of the glottis are thought to be driven by aneural oscillatorwhich generates a cycle of contraction and release every 30-40 milliseconds (giving a frequency of 33 to 25 Hz).[113][117][118] Grooming  The hookedpapillaeon a cat's tongue act like ahairbrushto help clean and detangle fur Cats are known for spending considerable amounts of time licking their coats to keep them clean.[119]The cat's tongue has backward-facing spines about 500μmlong, which are calledpapillae. These containkeratinwhich makes them rigid[120]so the papillae act like a hairbrush. Some cats, particularly longhaired cats, occasionally regurgitatehairballsof fur that have collected in their stomachs from grooming. These clumps of fur are usually sausage-shaped and about2–3cm (3⁄4–1+1⁄4in) long. Hairballs can be prevented with remedies that ease elimination of the hair through thegut, as well as regular grooming of the coat with a comb or stiff brush.[119] Fighting  A domestic cat's arched back, raised fur and an open-mouthed hiss are signs of aggression Among domestic cats, males are more likely to fight than females.[121]Among feral cats, the most common reason forcat fightingis competition between two males to mate with a female. In such cases, most fights are won by the heavier male.[122]Another common reason for fighting in domestic cats is the difficulty of establishing territories within a small home.[121]Female cats also fight over territory or to defend their kittens. Neutering will decrease or eliminate this behavior in many cases, suggesting that the behavior is linked tosex hormones.[123] When cats become aggressive, they try to make themselves appear larger and more threatening by raising their fur, arching their backs, turning sideways and hissing or spitting.[124]Often, the ears are pointed down and back to avoid damage to the inner ear and potentially listen for any changes behind them while focused forward. They may also vocalize loudly and bare their teeth in an effort to further intimidate their opponent. Fights usually consist of grappling and delivering powerful slaps to the face and body with the forepaws as well as bites. Cats also throw themselves to the ground in a defensive posture to rake their opponent's belly with their powerful hind legs.[125] Serious damage is rare, as the fights are usually short in duration, with the loser running away with little more than a few scratches to the face and ears. Fights for mating rights are typically more severe and injuries may include deep puncture wounds and lacerations. Normally, serious injuries from fighting are limited to infections of scratches and bites, though these can occasionally kill cats if untreated. In addition, bites are probably the main route of transmission offeline immunodeficiency virus.[126]Sexually active males are usually involved in many fights during their lives, and often have decidedly battered faces with obvious scars and cuts to their ears and nose.[127] Hunting and feeding See also:Cat nutrition  A domestic cat with its prey, adeermouse Cat "playing" with a mouse is interrupted by dog in Estonia, Kõrvemaa (July 2022) The shape and structure of cats' cheeks is insufficient to allow them to take in liquids using suction. Therefore, when drinking they lap with the tongue to draw liquid upward into their mouths. Lapping at a rate of four times a second, the cat touches the smooth tip of its tongue to the surface of the water, and quickly retracts it like a corkscrew, drawing water upward.[128][129] Feral cats and free-fed house cats consume several small meals in a day. The frequency and size of meals varies between individuals. They select food based on its temperature, smell and texture; they dislike chilled foods and respond most strongly to moist foods rich in amino acids, which are similar to meat. Cats reject novel flavors (a response termedneophobia) and learn quickly toavoid foods that have tasted unpleasantin the past.[104][130]It is also a common misconception that cats like milk/cream, as they tend to avoid sweet food and milk. Most adult cats arelactose intolerant; the sugar in milk is not easily digested and may cause soft stools ordiarrhea.[131]Some also develop odd eating habits and like to eat or chew on things like wool, plastic, cables, paper, string, aluminum foil, or even coal. This condition,pica, can threaten their health, depending on the amount and toxicity of the items eaten.[132] Cats hunt small prey, primarily birds and rodents,[133]and are often used as a form of pest control.[134][135]Cats use two hunting strategies, either stalking prey actively, orwaiting in ambushuntil an animal comes close enough to be captured.[136]The strategy used depends on the prey species in the area, with cats waiting in ambush outside burrows, but tending to actively stalk birds.[137]: 153 Domestic cats are a majorpredator of wildlifein the United States, killing an estimated 1.3 to 4.0 billion birds and 6.3 to 22.3 billion mammals annually.[138] Certain species appear more susceptible than others; in one English village, for example, 30% of house sparrow mortality was linked to the domestic cat.[139]In the recovery of ringed robins (Erithacus rubecula) and dunnocks (Prunella modularis) in Britain, 31% of deaths were a result of cat predation.[140]In parts of North America, the presence of larger carnivores such ascoyoteswhich prey on cats and other small predators reduces the effect of predation by cats and other small predators such asopossumsandraccoonson bird numbers and variety.[141] Perhaps the best-known element of cats' hunting behavior, which is commonly misunderstood and often appalls cat owners because it looks like torture, is that cats often appear to "play" with prey by releasing it after capture. Thiscat and mousebehavior is due to an instinctive imperative to ensure that the prey is weak enough to be killed without endangering the cat.[142] Another poorly understood element of cat hunting behavior is the presentation of prey to human guardians. One explanation is that cats adopt humans into their social group and share excess kill with others in the group according to thedominance hierarchy, in which humans are reacted to as if they are at, or near, the top.[143]Another explanation is that they attempt to teach their guardians to hunt or to help their human as if feeding "an elderly cat, or an inept kitten".[144]This hypothesis is inconsistent with the fact that male cats also bring home prey, despite males having negligible involvement in raising kittens.[137]: 153  Play Main article:Cat play and toys Play fight between kittens aged 14 weeks Domestic cats, especially young kittens, are known for their love of play. This behavior mimics hunting and is important in helping kittens learn to stalk, capture, and kill prey.[145]Cats also engage in play fighting, with each other and with humans. This behavior may be a way for cats to practice the skills needed for real combat, and might also reduce any fear they associate with launching attacks on other animals.[146] Cats also tend to play with toys more when they are hungry.[147]Owing to the close similarity between play and hunting, cats prefer to play with objects that resemble prey, such as small furry toys that move rapidly, but rapidly lose interest. They becomehabituatedto a toy they have played with before.[148]String is often used as a toy, but if it is eaten, it can become caught at the base of the cat's tongue and then move into theintestines, a medical emergency which can cause serious illness, even death.[149]Owing to the risks posed by cats eating string, it is sometimes replaced with alaser pointer's dot, which cats may chase.[150] Reproduction  When cats mate, the tomcat (male) bites the scruff of the female's neck as she assumes a position conducive tomatingknown aslordosis behavior. See also:Kitten Female cats, called queens, arepolyestrouswith severalestruscycles during a year, lasting usually 21 days. They are usually ready to mate between early February and August.[151] Several males, called tomcats, are attracted to a female in heat. They fight over her, and the victor wins the right to mate. At first, the female rejects the male, but eventually, the female allows the male to mate. The female utters a loud yowl as the male pulls out of her because a male cat'spenishas a band of about 120–150 backward-pointingpenile spines, which are about1mm (1⁄32in) long; upon withdrawal of the penis, the spines may provide the female with increased sexual stimulation, which acts toinduce ovulation.[152] After mating, the female cleans hervulvathoroughly. If a male attempts to mate with her at this point, the female attacks him. After about 20 to 30 minutes, once the female is finished grooming, the cycle will repeat.[153]Because ovulation is not always triggered by a single mating, females may not be impregnated by the first male with which they mate.[154]Furthermore, cats aresuperfecund; that is, a female may mate with more than one male when she is in heat, with the result that different kittens in a litter may have different fathers.[153] Themorulaforms 124 hours after conception. At 148 hours, earlyblastocystsform. At 10–12 days, implantation occurs.[155]Thegestationof queens lasts between 64 and 67 days, with an average of 65 days.[151][156]  Radiography of a pregnant cat. The skeletons of two fetuses are visible on the left and right of the uterus.  A newborn kitten Data on the reproductive capacity of more than 2,300 free-ranging queens were collected during a study between May 1998 and October 2000. They had one to six kittens perlitter, with an average of three kittens. They produced a mean of 1.4 litters per year, but a maximum of three litters in a year. Of 169 kittens, 127 died before they were six months old due to a trauma caused in most cases by dog attacks and road accidents.[9]The first litter is usually smaller than subsequent litters. Kittens are weaned between six and seven weeks of age. Queens normally reach sexual maturity at 5–10 months, and males at 5–7 months. This varies depending on breed.[153]Kittens reachpubertyat the age of 9–10 months.[151] Cats are ready to go to new homes at about 12 weeks of age, when they are ready to leave their mother.[157]They can be surgicallysterilized(spayed orcastrated) as early as seven weeks to limit unwanted reproduction.[158]This surgery also prevents undesirable sex-related behavior, such as aggression,territory marking(spraying urine) in males and yowling (calling) in females. Traditionally, this surgery was performed at around six to nine months of age, but it is increasingly being performed beforepuberty, at about three to six months.[159]In the United States, about 80% of household cats are neutered.[160] Lifespan and health Main articles:Cat healthandAging in cats The average lifespan of pet cats has risen in recent decades. In the early 1980s, it was about seven years,[161]: 33 [162]rising to 9.4 years in 1995[161]: 33 and about 15 years in 2021. Some cats have been reported as surviving into their 30s,[163]with the oldest known cat,Creme Puff, dying at a verified age of 38.[164] Neutering increases life expectancy: one study found castrated male cats live twice as long as intact males, while spayed female cats live 62% longer than intact females.[161]: 35 Having a catneuteredconfers health benefits, because castrated males cannot developtesticular cancer, spayed females cannot developuterineorovarian cancer, and both have a reduced risk ofmammary cancer.[165] Disease Main article:Feline diseases About 250 heritablegenetic disordershave been identified in cats, many similar to humaninborn errors of metabolism.[166]The high level of similarity among themetabolismof mammals allows many of these feline diseases to be diagnosed usinggenetic teststhat were originally developed for use in humans, as well as the use of cats asanimal modelsin the study of the human diseases.[167][168]Diseases affecting domestic cats include acute infections,parasitic infestations, injuries, and chronic diseases such askidney disease,thyroid disease, andarthritis.Vaccinationsare available for many infectious diseases, as are treatments to eliminate parasites such as worms, ticks, and fleas.[169] Ecology Habitats  Atabby catin snowy weather The domestic cat is acosmopolitan speciesand occurs across much of the world.[59]It is adaptable and now present on all continents exceptAntarctica, and on 118 of the 131 main groups of islands, even on the isolatedKerguelen Islands.[170][171]Due to its ability to thrive in almost any terrestrial habitat, it is among the world's mostinvasive species.[172]It lives on small islands with no human inhabitants.[173]Feral cats can live in forests, grasslands, tundra, coastal areas, agricultural land, scrublands, urban areas, and wetlands.[174] The unwantedness that leads to the domestic cat being treated as an invasive species is twofold. On one hand, as it is little altered from the wildcat, it can readily interbreed with the wildcat. Thishybridizationposes a danger to the genetic distinctiveness of some wildcat populations, particularly inScotlandandHungary, possibly also theIberian Peninsula, and where protected natural areas are in close proximity to human-dominated landscapes, such asKruger National ParkinSouth Africa.[175][56]On the other hand, and perhaps more obviously, its introduction to places where no native felines are present contributes to the decline of native species.[176] Ferality Main article:Feral cat  Feralfarm cat Feral cats are domestic cats that were born in or have reverted to a wild state. They are unfamiliar with and wary of humans and roam freely in urban and rural areas.[10]The numbers of feral cats is not known, but estimates of the United States feral population range from 25 to 60 million.[10]Feral cats may live alone, but most are found in largecolonies, which occupy a specific territory and are usually associated with a source of food.[177]Famous feral cat colonies are found in Rome around theColosseumandForum Romanum, with cats at some of these sites being fed and given medical attention by volunteers.[178] Public attitudes toward feral cats vary widely, from seeing them as free-ranging pets to regarding them as vermin.[179] Some feral cats can be successfully socialized and 're-tamed' for adoption; young cats, especially kittens[180]and cats that have had prior experience and contact with humans are the most receptive to these efforts. Impact on wildlife Main article:Cat predation on wildlife On islands, birds can contribute as much as 60% of a cat's diet.[181]In nearly all cases, the cat cannot be identified as the sole cause for reducing the numbers of island birds, and in some instances, eradication of cats has caused a "mesopredator release" effect;[182]where the suppression of top carnivores creates an abundance of smaller predators that cause a severe decline in their shared prey. Domestic cats are a contributing factor to the decline of many species, a factor that has ultimately led, in some cases, to extinction.The South Island piopio,Chatham rail,[140]and theNew Zealand merganser[183]are a few from a long list, with the most extreme case being the flightlessLyall's wren, which was driven to extinction only a few years after its discovery.[184][185]One feral cat in New Zealand killed 102New Zealand lesser short-tailed batsin seven days.[186]In the US, feral and free-ranging domestic cats kill an estimated 6.3 – 22.3 billion mammals annually.[138] In Australia, the impact of cats on mammal populations is even greater than the impact of habitat loss.[187]More than one million reptiles are killed by feral cats each day, representing 258 species.[188]Cats have contributed to the extinction of theNavassa curly-tailed lizardandChioninia coctei.[176] Interaction with humans Main article:Human interaction with cats  A cat sleeping on a man's lap Cats are commonpetsthroughout the world, and their worldwide population as of 2007 exceeded 500million.[189]Cats have been used for millennia to control rodents, notablyaround grain storesandaboard ships, and both uses extend to the present day.[190][191] As well as being kept as pets, cats are also used in the internationalfur trade[192]and leather industries for making coats, hats, blankets, and stuffed toys;[193]and shoes, gloves, and musical instruments respectively[194](about 24 cats are needed to make a cat-fur coat).[195]This use has been outlawed in the United States since 2000 and in the European Union (as well as the United Kingdom) since 2007.[196] Cat pelts have been used for superstitious purposes as part of the practice ofwitchcraft,[197]and are still made into blankets inSwitzerlandastraditional medicinethought to curerheumatism.[198] A few attempts to build a cat census have been made over the years, both through associations or national and international organizations (such as that of theCanadian Federation of Humane Societies[199]) and over the Internet,[200][201]but such a task does not seem simple to achieve. General estimates for the global population of domestic cats range widely from anywhere between 200 million to 600 million.[202][203][204][205][206]Walter Chandohamade his career photographing cats after his 1949 images ofLoco, an especially charming stray taken in, were published around the world. He is reported to have photographed 90,000 cats during his career and maintained an archive of 225,000 images that he drew from for publications during his lifetime.[207] Shows Main article:Cat show Acat showis a judged event in which the owners of cats compete to win titles in various cat-registering organizations by entering their cats to be judged after a breed standard.[208]It is often required that a cat must be healthy and vaccinated in order to participate in a cat show.[208]Bothpedigreedand non-purebredcompanion ("moggy") cats are admissible, although the rules differ depending on the organization. Competing cats are compared to the applicable breed standard, and assessed for temperament.[208] Infection Main article:Feline zoonosis Cats can be infected or infested withviruses,bacteria,fungus,protozoans,arthropodsor worms that can transmit diseases to humans.[209]In some cases, the cat exhibits nosymptomsof the disease.[210]The same disease can then become evident in a human. The likelihood that a person will become diseased depends on the age andimmunestatus of the person. Humans who have cats living in their home or in close association are more likely to become infected. Others might also acquire infections from catfecesandparasitesexiting the cat's body.[209][211]Some of the infections of most concern includesalmonella,cat-scratch diseaseandtoxoplasmosis.[210] History and mythology Main articles:Cultural depictions of catsandCats in ancient Egypt Inancient Egypt, cats wereworshipped, and the goddessBastetoften depicted in cat form, sometimes taking on the war-like aspect of a lioness. The Greek historianHerodotusreported that killing a cat was forbidden, and when a household cat died, the entire family mourned and shaved their eyebrows. Families took their dead cats to the sacred city ofBubastis, where they were embalmed and buried in sacred repositories. Herodotus expressed astonishment at the domestic cats in Egypt, because he had only ever seen wildcats.[212] Ancient Greeks and Romans keptweaselsas pets, which were seen as the ideal rodent-killers. The earliest unmistakable evidence of the Greeks having domestic cats comes from two coins fromMagna Graeciadating to the mid-fifth century BC showing Iokastos and Phalanthos, the legendary founders ofRhegionandTarasrespectively, playing with their pet cats. The usual ancient Greek word for 'cat' wasailouros, meaning 'thing with the waving tail'. Cats are rarely mentioned inancient Greek literature.Aristotleremarked in hisHistory of Animalsthat "female cats are naturallylecherous." The Greeks latersyncretizedtheir own goddessArtemiswith the Egyptian goddess Bastet, adopting Bastet's associations with cats and ascribing them to Artemis. InOvid'sMetamorphoses, when the deities flee to Egypt and take animal forms, the goddessDianaturns into a cat.[213][214] Cats eventually displacedweaselsas the pest control of choice because they were more pleasant to have around the house and were more enthusiastic hunters of mice. During theMiddle Ages, many of Artemis's associations with cats were grafted onto theVirgin Mary. Cats are often shown in icons ofAnnunciationand of theHoly Familyand, according toItalian folklore, on the same night that Mary gave birth toJesus, a cat inBethlehemgave birth to a kitten.[215]Domestic cats were spread throughout much of the rest of the world during theAge of Discovery, asships' catswere carried onsailing shipsto control shipboard rodents and as good-luck charms.[50] Several ancient religions believed cats are exalted souls, companions or guides for humans, that are all-knowing but mute so they cannot influence decisions made by humans. In Japan, themaneki nekocat is a symbol of good fortune.[216]InNorse mythology,Freyja, the goddess of love, beauty, and fertility, is depicted as riding a chariot drawn by cats.[217]InJewish legend, the first cat was living in the house of the first manAdamas a pet that got rid ofmice. The cat was once partnering with the first dog before the latter broke an oath they had made which resulted in enmity between the descendants of these two animals. It is also written that neither cats norfoxesare represented in the water, while every other animal has an incarnation species in the water.[218]Although no species are sacred in Islam,cats are revered by Muslims. Some Western writers have statedMuhammadhad a favorite cat,Muezza.[219]He is reported to have loved cats so much, "he would do without his cloak rather than disturb one that was sleeping on it".[220]The story has no origin in early Muslim writers, and seems to confuse a story of a laterSufisaint,Ahmed ar-Rifa'i, centuries after Muhammad.[221]One of the companions of Muhammad was known asAbu Hurayrah("father of the kitten"), in reference to his documented affection to cats.[222]  The ancient Egyptiansmummifieddead cats out of respect in the same way that they mummified people[4]  AncientRoman mosaicof a cat killing apartridgefrom theHouse of the FauninPompeii  A 19th-century drawing of a tabby cat Superstitions and rituals  Some cultures are superstitious about black cats, ascribing either good or bad luck to them Many cultures have negativesuperstitionsabout cats. An example would be the belief that encountering ablack cat("crossing one's path") leads to bad luck, or that cats are witches'familiarsused to augment a witch's powers and skills. The killing of cats in MedievalYpres,Belgium, is commemorated in the innocuous present-dayKattenstoet(cat parade).[223]In mid-16th century France,cats would be burnt aliveas a form of entertainment. According toNorman Davies, the assembled people "shrieked with laughter as the animals, howling with pain, were singed, roasted, and finallycarbonized".[224] James Frazerwrote that "It was the custom to burn a basket, barrel, or sack full of live cats, which was hung from a tall mast in the midst of the bonfire; sometimes afoxwas burned. The people collected the embers and ashes of the fire and took them home, believing that they brought good luck. The French kings often witnessed these spectacles and even lit the bonfire with their own hands. In 1648Louis XIV, crowned with a wreath of roses and carrying a bunch of roses in his hand, kindled the fire, danced at it and partook of the banquet afterwards in the town hall. But this was the last occasion when a monarch presided at the midsummer bonfire in Paris. AtMetzmidsummer fires were lighted with great pomp on the esplanade, and a dozen cats, enclosed inwickercages, were burned alive in them, to the amusement of the people. Similarly, atGap, in thedepartmentof theHautes-Alpes, cats used to be roasted over the midsummer bonfire."[225] According to a myth in many cultures, cats have multiple lives. In many countries, they are believed to have nine lives, but in Italy, Germany, Greece, Brazil and some Spanish-speaking regions, they are said to have seven lives,[226][227]while in Arabic traditions, the number of lives is six.[228]The myth is attributed to the natural suppleness and swiftness cats exhibit to escape life-threatening situations.[citation needed]Also lending credence to this myth is the fact that falling cats often land on their feet, using an instinctiverighting reflexto twist their bodies around. Nonetheless, cats can still be injured or killed by a high fall.