Leatherback sea turtles are the largest of all living turtles, as well as being the fourth-heaviest modern reptile behind three crocodiles. Another name for the Leatherback includes lute turtle, leathery turtle or simply the luth. Unlike other modern turtles, it does not have a bony shell and its carapace is covered by skin and oily flesh. The Leatherback first got its name in 1761 from Domenico Agostino Vandelli.
Of all of the sea turtles, the Leatherback has the most hydrodynamic body design with its large teardrop-shaped body. Large front flippers power the turtles through the water, and like other sea turtles, the flattened forelimbs adapt for swimming in the open ocean. The Leatherback does not have claws in either pair of flippers. Further, their flippers are the largest in proportion to its body. The front flippers can grow up to 8.9 feet.
Characteristics that distinguish it from other sea turtles are its scutes instead of a bony carapace. They have a thick leathery skin with embedded minuscule osteoderms. As well, there are seven distinct ridges that rise from the carapace, crossing from the cranial to the caudal margin of the turtle’s back. Unique among reptiles, their scales lack B-keratin. A Leatherback’s entire dorsal surface is colored dark grey to black, with white blotches and spots.
Leatherbacks don’t have teeth. Instead, they have points on the tomium of its upper lip, and backward spines in its throat to help it swallow food. The backward spines stop its prey from escaping once caught.
Quite cosmopolitan with its global range, the Leatherback has the widest distribution. It reaches from as far north as Alaska and Norway to as far south as Cape Agulhas in Africa. You can also find them in the southmost tip of New Zealand. They are also found in all tropical and subtropical oceans. In the Atlantic Ocean, the Leatherback population crosses the entire region. Unlike other sea turtles, they feed in colder waters where there is an abundance of jellyfish and keep the jellyfish population under control. They will also feed on soft-bodied organisms like tunicates and cephalopods.
You will find Leatherbacks primarily in the open ocean. They follow jellyfish during the day, which keeps them in deeper water. At night, they move to shallower water when the jellyfish have risen. They are known to pursue prey deeper than 1000 m – far beyond the physiological limits of other diving tetrapods. Their lifespan is unknown. Reports estimated that they live between 30 and 50 years.
Surprisingly, people around the world still harvest sea turtle eggs. Exploitation of turtle nests in Asia has been cited as the most significant factor for a global population decline. Egg harvesting in Thailand and Malaysia has led to a near-total collapse of local nesting populations.
Leatherbacks have few natural predators once they mature. They have slightly fewer human-related threats than other sea turtles, due to the oil and fat in their flesh which is not considered palatable. However, they do get entangled in lobster pot ropes and ingest balloons and plastic bags which resemble jellyfish. Once these items are ingested, they die from malabsorption and intestinal blockage.
There are global and national initiatives trying to save the Leatherback sea turtle. In many parts of the world, it is illegal to export or import them. The Leatherback Trust was founded specifically to conserve sea turtles. A sanctuary in Costa Rica was established by the foundation.