Turtle model

thingiverse

Turtles make up the order Testudines (or Chelonii), a group of reptiles defined by their distinctive shell, formed from bony or cartilaginous material that has grown out of their ribs and acts as a protective shield.[4] While the term "turtle" usually refers to any reptile within this group in American English, in British English it often specifically describes fresh-water and sea-dwelling members of the order.[5]\nThe order Testudines is made up of living and extinct species alike. Fossil records show that this group emerged over 157 million years ago,[1] establishing turtles as one of the oldest groups of reptiles, even more ancient than snakes or crocodilians. At present, there are 327 known species, with many facing severe threats to their survival.[6][7]\nTurtles have an ectothermic nature, meaning that their internal temperature shifts in accordance with the external environment. Interestingly, however, the leatherback sea turtle boasts a higher body temperature than its aquatic surroundings due to its high metabolic rate.\nAs part of the larger group known as amniotes, turtles share many characteristics with other reptiles, birds, and mammals. They breathe air, lay eggs that must be incubated on land, and are able to live both in and around water, despite this being somewhat unconventional for many species within their ranks.