Sea turtles are characterized by a large, streamlined shell and nonretractile head and limbs. Depending on the species, sea turtles range in color. The green sea turtle gets its name from the color of its body fat. A sea turtle cannot retract its limbs under its shell as a land turtle can. Flippers are adapted for swimming.
Sea turtles are awkward and vulnerable on land.
Foreflippers are long and paddlelike. Long digits are fused throughout the flipper. Only one or two claws are present on each foreflipper. A sea turtle swims with powerful winglike beats of its foreflippers. Hind flippers serve as rudders, stabilizing and directing the animal as it swims.