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. The hind flippers of some species are quite dexterous in digging nests in the sand. A sea turtle cannot retract its head under its shell as a land turtle can.
Sea turtles have large upper eyelids that provide protection for their eyes.
Sea turtles do not have an external ear opening. Like other turtles, sea turtles lack teeth. Jaw shape varies among species. Each species has a jaw shape adapted for its diet. The large, bony shell provides protection from predation and abrasion.