Leatherback turtle is the largest living sea turtle. It is called the leatherback turtle because its shell is covered in a rubbery, leatherlike skin. Leatherback turtles are found in the tropical and temperate waters of oceans around the world.
The skin of the leatherback turtle is black with white spots. The leathery shell has seven ridges running front to back. The leatherback turtle has large flippers to help it to swim underwater and to bury its eggs in the sand. A leatherback turtle can grow up to about 8 feet (2.4 meters) in length. It can weigh up to about 2,000 pounds (900 kilograms). The leatherback turtle is one of the fastest-growing reptiles, reaching adult size in about 15 years.
Jellyfish make up most of the leatherback turtle’s diet. The turtle sometimes eats other soft-bodied marine animals, such as siphonophores. The leatherback turtle’s jaw has a sharp edge for biting its food.
The nesting season of the leatherback turtle varies in different parts of the world. Female leatherback turtles usually nest every 2 or 3 years. Each female lays around 7 clutches during the nesting season, leaving the water each time to lay eggs on a warm, sandy beach. A mother leatherback turtle uses her flippers to dig a hole in the sand, where she lays around 80 eggs. Then, she buries the eggs to keep them warm and protect them from predators (hunting animals). Around 65 days later, the eggs hatch. Hatchlings emerge from the nest at night and crawl to the sea. 
Leatherback turtles migrate longer distances than any other sea turtle. They can swim more than 10,000 miles (16,000 kilometers) per year. They migrate between their breeding and feeding waters. Leatherback migrations follow their preferred food source—jellyfish. Leatherback turtles can also dive deeper than other sea turtles to reach their food. They can dive to depths of more than 3,000 feet (1,000 meters). The leatherback’s flexible shell helps it to withstand the extreme pressure of the deep ocean.
The leatherback turtle’s large size and layer of insulating fat help to keep its internal body temperature high. This adaptation enables it to tolerate colder water temperatures than other sea turtles. When a leatherback turtle is in a warm climate or is exerting itself, blood vessels in its skin expand. Blood then carries excess body heat to the skin. Some patches of skin appear pink due to the increased blood flow.
Many different human activities threaten the nesting areas of leatherback turtles. Some people hunt the turtles and take their eggs for food. Dogs eat eggs and hatchlings. Bright lights often confuse hatchlings, causing them to get lost after they leave the nest. Young leatherbacks are often caught as bycatch of commercial fishing using gill nets and long-lines. Bycatch includes fish and other marine animals that are accidentally captured along with target fish species. Leatherbacks may eat plastic bags floating in the ocean because they resemble jellyfish. If the turtles cannot pass the bags through their digestive system, they can starve. Many countries have made laws to protect the leatherback turtle.
