[originaltext] The turtle is a reptile with a bony or leathery shell. Any sh

The turtle is a reptile with a bony or leathery shell. Any shelled reptile can be called a turtle, but in North America people commonly use the word tortoise to refer to members of a family of turtles that live entirely on land, reserving the word turtle for species that live in or near water.
    Turtles are ancient life forms that first appeared on Earth during the Triassic Period, which extended from about 240 million to 205 million years ago. Turtles survived the disasters that wiped out the dinosaurs and many other creatures at the end of the Mesozoic Era about 65 million years ago.
    There are about 270 living species of turtles, which are grouped into 12 or 13 families. These families axe further classified into two suborders: side-necked turtles and hidden-necked turtles. Side-necked turtles protect their heads by folding their necks sideways under the top edge of the shell. Hidden-necked turtles pull their heeds directly into the shell, using an up-and-down motion of the neck. Hidden-necked turtles are more widespread than side-necked turtles, Sea turtles, as well as a few other kinds of turtles, are considered members of the hidden-necked group even though they cannot fully withdraw their heeds.
    Turtles inhabit every continent except Antarctica. Like all living reptiles, turtles are cold-blooded animals whose body temperature is influenced by the outside environment. For this reason, turtles are most abundant in warm tropical and subtropical climates.