Turtles

Turtles are reptiles of the order Chelonia /kɪˈloʊniə/ or Testudines /tɛˈstjuːdɪniːz/. They are characterized by a bony or cartilaginous shell or carapace,

developed from their ribs, that acts as a shield.[3] Testudines includes both extant (living) and extinct species. Its earliest known members date from the Middle Jurassic.[1] They are one of the oldest reptile groups, more ancient than snakes or crocodilians.

Turtles are ectotherms—commonly called cold-blooded—meaning that their internal temperature varies according to the ambient environment. However, because of their high metabolic rate, leatherback sea turtles have a body temperature that is noticeably higher than

that of the surrounding water. Turtles are classified as amniotes, along with other reptiles, birds, and mammals. Like other amniotes, turtles breathe air and do not lay eggs underwater, although many species live in or around water.