Shelled Reptiles have shells on them for protection. These kinds of reptiles are harmless.

Terrapins

Terrapins are the kind of shelled reptiles living in fresh water. Their shells are flatter as compared to the tortoises. They can hold their breath for a long time, and some species have pointed snouts so that they are barely visible when they come up for air. They are flesh eaters. Some are like the alligator snapper; lie in wait for unwary fish or smaller creatures. It lies with its mouth open, and at the back of its tongue there is a small worm-like organ. If a fish tries to eat this worm, the snapper has an easy meal. Other species are hunters, some are even being powerful and quick enough to catch ducks.

Tortoises

Tortoises lie among the armored reptiles. They are well protected against enemies, but their domed sells are heavy, so they are slow-moving creatures. They protect themselves by puling their heads, tails and legs into their shells. To breathe, tortoises must pump air into their lungs using special muscles since, like turtles, their shells stop their rib cages expanding. At one time giant tortoises were found on many remote tropical islands. Unfortunately, most of these are now extinct, but the few that survive are carefully preserved. Many other species of tortoise are threatened by damage to the environment or hunting.

Turtles

Turtles have toothless jaws, which are edged with sharp bone to chop up their food. The largest turtles feed on many sorts of marine plants and animals, including jellyfish. They spend most of their lives at sea, but during the breeding season they visit shallow water to mate, then at night the females come ashore to lay their eggs. They take most of the night to dig a pit and lay up to 200 eggs. These take about three months to hatch. The young turtles then dig their way out of the nest and go down to the sea. They have many predators including humans and large numbers of turtles are killed before they are old enough to breed.