A Beautiful Colorful Turtle Swimming Underwater

A reptile with a bony body, like tortoises, is referred to as a turtle. While many animals have evolved shells, from invertebrates to mammals, none have the architecture of turtles. There is a top (carapace) and a bottom of the turtle head (plastron).

The carapace and plastron are bony structures that normally connect to form a compact skeletal box around either side of the body. This enclosure, made of bone and cartilage, is kept by the turtle throughout its existence. Since the turtle's shell is an essential part of its body, it cannot be removed, nor can it be shed like the skin of other reptiles.

There are roughly 356 species of turtles that live on land, in both salt and fresh water, on all continents except Antarctica. Tortoises (family Testudinidae) are the only turtles that exist solely on land and have anatomical characteristics that differentiate them from other turtles. However, the name tortoise has long been used to refer to other terrestrial testudines, such as the box turtle and the wood turtle. Similarly, the term terrapin was once used to describe any marine turtle but is now mostly limited to the eastern United States' edible diamondback terrapin (Malaclemys terrapin).

Despite their vast range, turtles may not seem to have had a significant number of species at any stage during their long evolutionary period. However, a reduced number of species does not mean a lack of variety.

There are turtles with carapace lengths of less than 10 cm (4 inches), such as the flattened musk turtle (Sternotherus depressus), and turtles with carapace lengths of more than 1.5 metres (4.9 feet), such as the leatherback sea turtle (Dermochelys coriacea).

Some species live in seasonally cold climates with three-month growth seasons, while others live in the tropics and grow all year. Some tortoises never see water, while others spend their whole life floating in it, whether in a shallow pond or across the vast open ocean.

Turtles are kept as pets, both common and rare. Pond turtles like the red-eared slider (Trachemys scripta) and cooters (Pseudemys species) can be found in pet shops all over the Western Hemisphere. Since some turtles are present only in limited geographic areas or do not reproduce in captivity, their ornate shells make them attractive as pets, but they are also vulnerable to extinction in the wild.

Tortoiseshell from the hawksbill sea turtle (Eretmochelys imbricata) was used in eyeglass lenses and novelty pieces until the invention of plastics. Turtles and their eggs have long been consumed in many parts of the world, and their market value remains high. Local populations and even whole species have been hunted to extinction in certain regions.