The largest leatherback ever recorded was a male of 914 kg and 2.6 m length that stranded on the west coast of Wales in 1988. The front flippers are proportionally longer than in any other sea turtle, and may span 2.7 m. warm inside, dives to 4000' The core body temperature of adults in cold water can be up to 18 degrees C above the surrounding water. They can rest submerged for 2 hours, and can dive to 4000 feet. They are immune to Coelenterate toxins. Their success in feeding on food of such low energy density may be due to their ability to find deepwater jellyfish very efficiently from their bioluminescence.
All sea turtles lay their eggs in nests dug in open sandy beaches.
Leatherbacks differ from other sea turtles in their low beach fidelity, which hampers population estimation. Age at sexual maturity is unknown. Small turtles are rarely seen after they have left the beaches and their habitat is unknown. Population trends and Distribution Range - to the Arctic Circle 18 reported in Cornwall in 1988 The Leatherback ranges as far as the Arctic Circle. They are regularly seen in the Celtic Sea, with occasional sightings from the coasts of Cornwall and Devon and a long history of strandings.