The leatherback is the largest reptile and can weigh up to one ton. The carapace (top shield) does not have scales like other sea turtles. It is covered with a thick, leathery, oily skin. The dark brown or black carapace has seven large ridges. It's head is huge compared to the body. The front flippers are big compared to the hind flippers. Males have a concave plastron (bottom shell) and a tail longer than their hind limbs. Female tails are not as long.

The leatherback will migrate great distances to get to a nesting beach and may be found as far north as Canada and the northern Pacific Ocean. They go as far south as the Caribbean and U.S Islands. Artificial lights, due to commercial development disturb the nesting sites. Turtles are attracted to these lights and this increases their chance of death or injury.

The main food for the leatherback is jellyfish. Sometimes a turtle will mistake an inflated plastic bag for a jellyfish and eat the bag. The bag blocks the digestive tract and kills the turtle. Another reason that this turtle population is decling is people steal the eggs for food.

Leatherbacks are sometimes caught in shrimping nets. Before the use of turtle excluder devices, about 640 leatherbacks a year were accidently captured. Since Leatherbacks are so large the TEDs can not always allow the turtle to pass through the escape door. The Leatherback is listed as endangered under the Endangered Species Act of 1973.