Leatherback Sea Turtle

The leatherback sea turtle is the largest of all living sea turtles and one of the largest living reptiles overall, capable of reaching nearly two metres in shell length and weighing several hundred kilograms, distinguished from all other sea turtles by its rubbery, leathery skin rather than a hard, bony shell, which is instead composed of small bone plates embedded beneath a thick layer of oily connective tissue. It has an unusually wide range for a reptile, tolerating colder waters than any other sea turtle thanks to a form of internal heat regulation that lets it maintain a body temperature warmer than its surroundings even in near-freezing seas. Leatherbacks feed almost entirely on jellyfish and other soft-bodied invertebrates, and they undertake some of the longest migrations of any marine reptile, crossing entire ocean basins between feeding and nesting grounds. The species has declined severely across much of its range due to egg poaching, bycatch in fishing gear and ingestion of plastic debris mistaken for jellyfish, and several regional populations are now considered critically endangered.