Turtle biography
7 levels of classification for a turtle.
Turtle
Order of reptiles characterized by a shell
For other uses, see Turtle (disambiguation).
See also: Tortoise
"Chelonian" redirects here.
For other uses, see Chelonian (disambiguation).
Turtles are reptiles of the orderTestudines, characterized by a special shell developed mainly from their ribs.
Turtle biography
Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Cryptodira (hidden necked turtles), which differ in the way the head retracts. There are 360 living and recently extinct species of turtles, including land-dwelling tortoises and freshwater terrapins.
They are found on most continents, some islands and, in the case of sea turtles, much of the ocean. Like other amniotes (reptiles, birds, and mammals) they breathe air and do not lay eggs underwater, although many species live in or around water.
Turtle shells are made mostly of bone; the upper part is the domed carapace, while the underside is the flatter plastron or belly-plate. Its ou