Wild animals mammals

Mammals (plural "mammal") or breasts (Latin: Mammalia) are a class or biological class that branches off from the vertebrate phylum (Latin: Vertebrata) in the animal world, its name derived from the word "breast" (in Latin: Mamma). Mammals are also a vital branch of amniotes endothermic. Mammals are distinguished from other amniotes, such as reptiles (including birds), by some characteristics such as the hair that covers their bodies, the three ossicles in the middle ear (hearing ossicles), the mammary glands in females, and the neocortex in the brain. Females of all types of mammals feed their young with milk, which is secreted by the mammary glands.

In mammals, the brain regulates body temperature and circulation, including the four-chambered heart. Mammals include the largest animals on the planet, such as fin whales, as well as some of the most intelligent like elephants as well as some primates and cetaceans. The main feature of their bodies is the four legs that they carry on land, but some mammals adapt to life in the sea, in the air, in trees, or on two legs. The largest group of mammals, the true mammals, have a placenta that nourishes their young during pregnancy. Mammals range in size from 30-40 millimeters (1-1.5 inches) like a bumblebee bat to 33-meter (108 feet) like the blue whale.

According to the World Mammalian Species Book, as of 2006 5,702 species of mammals were known. They are grouped into 1,229 genera, 153 families and 29 ranks. [5] In 2008, for a period of five years, the International Union for Conservation of Nature (IUCN) completed 17,000 global mammalian scientific assessments of its IUCN Red List, which totaled 5,488 acceptable species at the end of that period. [6] Mammals in some classifications are divided into two sub-divisions (excluding the fossils): protozoan (order monotremes) and neonatal, with the latter forming without the class of marsupials and true mammals. The marsupial animals include a crown group of marsupials and thus include them all, in addition to the large extinct numbers. Likewise, the placenta forms the crown group of true mammals.

All mammals give birth except for the five monotremes (which lay eggs). Most mammals, including the six species-rich orders, belong to the placental group. The three largest (descending) are:

Rodents: (mice and rats, porcupines, beavers, water boars, and others).

Bats: (bats).

Marinids: (shrews, moles and solenoids).

The three largest ranks based on the bio-classification used are:

Primates: They belong to the human race.

Dactylated cetaceans: (includes alpha toes and whales),

Carnivores: (cats, dogs, weasels, bears, seals, and their relatives). [5]

Whereas, the classification of mammals at the family level is stable with different distributions at higher levels, especially for marsupials. Recently, a great change has occurred, which is reflected in the results of cladistics and molecular genetics. The results of molecular genetics, for example, led to the adoption of new groups such as Africans and the abandonment of traditional groups such as insectivores.

The ancestors of the mammalian snapsids were the wedge of plycosaur teeth, the group that also includes dimetrodon. At the end of the Carboniferous period, this group of sauropsids branched out leading to the reptiles and birds of this day. Preceded by many diverse groups of non-mammalian snapsids (sometimes called semi-mammalian reptiles), the first mammals appeared at the beginning of the Mesozoic Era. The modern mammalian orders of the Paleogene and Neogene epochs arose from the Sennoese era.