Leatherbacks are enormous: they can grow up to 2 metres long and weigh up to 900 kilograms - about the same as a small car. Unlike other sea turtles, they do not have a hard shell. Instead they have a tough, leathery skin stretched over a flexible, rubbery carapace, which is where they get their name.
A leatherback turtle's life is one long journey. They swim thousands of kilometres across the open ocean, diving to depths of over 1,000 metres - deeper than almost any other air-breathing animal. They feed almost entirely on jellyfish. Because jellyfish have very little nutrition, a leatherback has to eat enormous quantities - sometimes its own body weight in jellyfish each day.
When a female leatherback comes ashore to nest, she hauls herself up the beach using her powerful front flippers. She digs a deep hole in the sand with her back flippers, lays around 80 eggs, carefully covers them and then heads straight back to the sea. About two months later, the tiny hatchlings dig their way out and scramble towards the moonlit water. It is one of nature's most magical sights.