Turtles (Testudines) are an order of reptiles of which all species are characterized by an often sturdy and spherical shell.
Turtles can vary greatly in size, colors and lifestyle, but are easily distinguished from all other reptiles by the outer shell. All turtles have a bony shell on both the ventral side (plastron) and the dorsal side (carapace), unlike all other modern reptiles such as crocodilians, lizards and snakes. The shield is usually provided with a second armour, the horn shield. The carapace is connected to the abdominal armor by a bone bridge on either side of the body.
Turtles usually reproduce annually and are without exception oviparous. They grow quickly when young but develop very slowly. Larger tortoises only mature after several decades, but such species can also become very old. The menu includes both animal and vegetable material, depending on the species.
There are about 355 different species of turtles, divided into fourteen families. Turtles are found all over the world, with the exception of the poles, in a variety of habitats, such as forests, grasslands, swamps and seas. Dozens of species are seriously threatened by human activities. The main threats are habitat destruction and the collection of wild turtles for consumption or the pet trade.
Distribution and habitat
Turtles are found on almost all continents, but only in tropical and subtropical regions. Especially in Africa many species live, in Europe turtles live only in the south around the Mediterranean, in Asia only in the southern part. Only some of the land-dwelling species occur in temperate areas. In North America the turtles are found in the south and central, in South America turtles are only missing in the extreme western coastal strip. In Oceania, the turtles live on much of the associated islands, but not in New Zealand. In Australia, the tortoises are found everywhere, except in a large desert area in Central Australia. In the Arabian Peninsula, species live in both the north and the extreme south, but are absent from most of the central part. The only areas where turtles are not found today are the North and South Poles. The distribution map on the right shows the worldwide distribution of the turtles in black, and the distribution of the marine turtles in blue.
In terms of habitat, the turtles are roughly divided into the tortoises, the swamp dwellers and the sea turtles. However, this division has no scientific basis; for example, marine species belong to different families. There are also species that belong to the terrapins but have adapted to a life on land, an example are the box turtles.
A turtle's habitat can consist of almost all possible habitats, from poor areas such as savannas and semi-deserts to forests, grasslands and swamps. Only in large lakes and in very hot deserts or cold mountain regions without shelters and vegetation are no turtles found. Turtles, like all reptiles, are cold-blooded, so they depend on the ambient temperature. Most species live in freshwater in swampy areas and regularly come to land to feed and bask, but stay close to water to escape from danger and rest. The sea turtles live permanently in the world's seas, some terrapins are also sometimes found in salt water, but only along the coast and in mangrove forests, not in the open sea.
Many turtles are good swimmers that use surface water as a shelter. Some species, such as softshell turtles, are so adapted to water that they