Turtle

related topics
{specie, animal, plant}
{@card@, make, design}
{island, water, area}
{food, make, wine}
{water, park, boat}
{rate, high, increase}

Cryptodira
Pleurodira
and see text

Turtles are reptiles of the order Testudines (the crown group of the superorder Chelonia), characterised by a special bony or cartilaginous shell developed from their ribs that acts as a shield. "Turtle" may either refer to the Testudines as a whole, or to particular Testudines which make up a form taxon that is not monophyletic—see also sea turtle, terrapin, tortoise, and the discussion below.

The order Testudines includes both extant (living) and extinct species. The earliest known turtles date from 215 million years ago,[2] making turtles one of the oldest reptile groups and a more ancient group than lizards, snakes and crocodiles. Of the many species alive today some are highly endangered.[3]

Like other reptiles, turtles are ectotherms—varying their internal temperature according to the ambient environment, commonly called cold-blooded. However, leatherback sea turtles have noticeably higher body temperature than surrounding water because of their high metabolic rate.

Like other amniotes (reptiles, dinosaurs, birds, and mammals), they breathe air and do not lay eggs underwater, although many species live in or around water. The largest turtles are aquatic.

Contents

Full article ▸

related documents
Butterfly
Cougar
Shark
Seahorse
Archaeopteryx
Snake
Orchidaceae
Bongo (antelope)
Grizzly Bear
Fossil
Great white shark
Biodiversity
Plant breeding
Brown Rat
Mollusca
Neanderthal
Bird
Arthropod
Beetle
Pterosaur
Eucalyptus
Ferret
Hybrid (biology)
Species
Dominance (genetics)
Pearl
Crocodile
Asexual reproduction
Flowering plant
Domestication of the horse