But as tourist development has encroached onto nesting beaches, the babies have become confused and have frequently headed towards the bright lights of discos, beach bars and cafes instead - only to collapse exhausted and be attacked by predators. Unlike tortoises and freshwater turtles, sea turtles have flippers instead of legs, are clawless and cannot withdraw their heads into their shells. Scientists disagree as to whether the black turtle is a further species or merely a subspecies of green turtle. The diet of the turtle varies according to the species. Green turtles are fond of sea grasses, while leatherbacks favour jellyfish.
Leatherbacks often mistake floating plastic bags for their favourite prey, with fatal consequences.
The leatherback is capable of travelling huge distances. Most marine turtles live in warm tropical and sub - tropical seas, but the leatherback also visits cooler waters. If global warming continues, we may see more of the leatherback and other species which make occasional appearances off the British coast. The olive and Kemp's ridley turtles are related and used to come ashore in huge numbers to lay their eggs. In the late 1940s more than 42,000 female Kemp's ridleys nested together in a single day - now, only some 900 make the same journey.