The world’s largest turtle lives and grows on a diet of clear, watery, jellylike animals. The revelation is a bit like hearing from a champion weightlifter that they have never eaten anything but cucumbers. How could a leatherback be the biggest and grow the fastest by feeding on animals that are 96% water? The answer is that leatherbacks apparently eat a lot. Juvenile leatherbacks that have lived briefly in captivity were able to eat twice their body weight in jelly- fish every day.