The largest of all reptiles, the leatherback sea turtle may reach 7 feet in length and weigh as much as 1,400 pounds. It measures 9 feet from the tip of one flipper to the tip of the other. Leatherbacks are the only turtles to have a thick layer of fat for insulation. They also have no visible shell. The shell is present but consists of bones buried into the turtle's dark brown or black skin. The leatherback has seven pronounced ridges in its back and five on the underside.
