The leatherback sea turtle is the largest of all the sea turtles, averaging 150 to 170 cm SCL (straight carapace length) and 500 kg. The largest leatherback recorded measured 3 m from the tip of its beak to the tip of its tail, and weighed 916 kg! As its name implies, leatherback turtles have a thick, black leathery skin instead of a hard shell (as all other sea turtles do). The rubber-like carapace (upper shell) is often white-spotted, with seven ridges that stretch from the head to the tail. The belly of the turtle is mottled with pinkish-white and black. The body is barrel-shaped, tapering to a blunt point at the rear end. Dermochelys coriacea have exceptionally long forelimbs (1 m), without claws. Hatchlings are mostly black, covered with tiny bead-like scales. Their flippers are rimmed with white, and small white rows of scales are apparent where the longitudinal ridges will eventually form on adults. Hatchlings are about 60 mm long and weigh approximately 45 g.
Can be Confused With
Dermochelys coriacea are unlikely to be confused with any other sea turtle because of their distinctive leathery black shell at all life stages. If identifying skeletal remains, leatherback turtles can be distinguished by their reduced skeleton (they lack many bones that are present in the shells of other sea turtles).
The leatherback sea turtle is the widest ranging of all sea turtles (cosmopolitan), and can be found from the tropics up into polar zone. Dermochelys coriacea is almost entirely pelagic, entering coastal waters infrequently except during the breeding season. However, leatherbacks are not uniformly pelagic; there are coastal populations, most notably along the North American Atlantic seabord. Adults are known to make long migrations that cross entire ocean basins. Very little is known about the pelagic distribution of post-hatchling or juvenile leatherbacks.
Leatherback nesting occurs exclusively in the tropics, except for a few nest in the subtropics (in Florida and South Africa). Nesting beaches typically lack a fringing reef, and exhibit high wave energy with a steep ascent. Leatherback nesting colonies have been identified in the Caribbean from Costa Rica to Colombia, from French Guiana to Surinam, along the central Brazilian coast, in Gabon, Guyana, Trinidad, the Dominican Republic, St. Croix, Malaysia, Thailand, Indonesia, and along the western coast of Mexico south to Panama.
Ecology and Behavior
Hatchling leatherback turtles leave the beach on which their mother nested and swim directly offshore, but very little is known about the early pelagic juvenile stage (often called "the lost years"). Leatherback turtles remain pelagic for most of their lives, foraging on the highseas and along continental shelves, and returning to land only for the purpose of laying eggs. Migrations between feeding grounds and distant nesting beaches have been established through satellite tracking studies, though it is uncertain whether leatherbacks make these lengthy migrations every year. Leatherbacks are believed to sexually mature at approximately 8 to 15 years old, far sooner than do other sea turtle species. Mating has been observed in the waters just off nesting beaches, but may also occur prior to or during a migration to the nesting ground. Females typically nest at night, though occasionally during daylight. The female leatherback ascends the beach, digs a nest, lays her clutch of eggs, and finally re-covers the nest with sand. A leatherback may lay multiple clutches (up to 12 per season, averaging 6 or 7) through the nesting season. Leatherbacks usually lay fewer eggs per clutch than other sea turtles (averaging 80 to 90 eggs in the Atlantic, or 60 eggs in the eastern Pacific). In addition to normal yolked eggs, a leatherback nest will also include some number of undersized yolkless eggs, the exact function of these eggs is unknown . Leatherbacks will migrate to the nesting grounds for reproduction every 2-5 or more years. Hatchlings incubate for a period of approximately 55-70 days before emerging; the sex ratio of hatchlings is determined by the temperature of the nest.
Feeding and Prey
Dermochelys coriacea prey on creatures in the water column, unlike many other sea turtles which forage for benthic (bottom dwelling) animals. Though they are primarily pelagic, they have been observed foraging over continental shelves and close to shore. The mouth and jaw of a leatherback turtle are specially adapted for their diet of soft-bellied organisms, primarily jellyfish. They have delicate, scissor-like jaws, and their throat musculature is such that they can suck in gelatinous organisms with a large inflow of water. Specialized spines in the esophagus then allow the turtle to retain the prey item while expelling the water. In captivity, juvenile leatherback turtles can eat twice their body weight in jellyfish every day.
Prey items include: Gelatinous zooplankton > Cephalopods (probably) > Misc. invertebrates (consumed only coincidentally with commensal jellyfish)
Caribbean Conservation Corporation/Sea Turtle Survival League. 2011. Species fact sheet: Leatherback sea turtle. Available online here.
Lutz, P.L and J.A. Musick, eds. 1997. The biology of sea turtles. CRC Press LLC, New York, NY.
National Marine Fisheries Service and U.S. Fish and Wildlife Service. 1992. Recovery plan for leatherback turtles in the U.S. Caribbean, Atlantic, and Gulf of Mexico. National Marine Fisheries Service, Washington, DC.
National Research Council. 1990. Decline of the sea turtles: Causes and prevention. National Academy Press, Washington, DC.