The Leatherback Sea Turtle (Dermochelys coriacea) is the largest sea turtle in the world. These powerful swimmers can reach lengths of up to 2.91 meters (9 feet 6 inches) and weigh over 960 kilograms (2,120 pounds), making them the largest living turtle and the heaviest non-crocodilian reptile on Earth.
Unmatched Size and Unique Anatomy
Adult leatherback sea turtles typically average between 1 and 1.75 meters (3.3 and 5.7 feet) in length and weigh from 250 to 700 kilograms (550 to 1,540 pounds). Unlike other sea turtles, leatherbacks lack a hard, bony shell. Instead, their carapace is covered by thick, flexible, leathery skin, which gives them their name.
Beneath this leathery skin lies a mosaic of thousands of small, interlocking dermal bones embedded within fatty, cartilaginous tissue. Seven distinct ridges run lengthwise along their carapace, which enhance swimming efficiency. Their body is streamlined and teardrop-shaped, tapering to a blunt point.
Leatherbacks possess the largest front flippers in proportion to their body among all sea turtles, reaching up to 2.7 meters (8.9 feet) in larger individuals. These long, paddle-like forelimbs lack claws, and their hind flippers are also paddle-shaped, contributing to their powerful swimming ability. Their coloration is typically dark bluish-black, often adorned with white, pink, or blue splotches on their carapace, neck, head, and flippers. A distinctive pink spot on their head is unique to each individual and may play a role in navigation during migrations.
A Life of Extremes
Leatherback sea turtles are highly migratory, traveling up to 16,000 kilometers (10,000 miles) annually between nesting and foraging grounds. Pacific leatherbacks journey from Southeast Asia to Alaskan waters; Atlantic populations migrate from Caribbean nesting sites to Canadian waters. This species has the widest global distribution of any reptile, inhabiting the Atlantic, Pacific, and Indian Oceans.
Leatherbacks tolerate colder water temperatures than other sea turtles due to unique physiological adaptations. They have a specialized diet of gelatinous organisms, primarily jellyfish, consuming up to 73% of their body mass daily. Their throats are lined with backward-pointing spines, called papillae, which help them swallow and prevent jellyfish from escaping.
Leatherbacks are also exceptional divers, reaching depths of nearly 1,200 meters (4,000 feet), with a recorded dive extending to 1,344 meters (4,409 feet). Their deep-diving adaptations include collapsible lungs and a flexible shell that withstands immense pressure. They maintain a core body temperature warmer than the surrounding water, a trait known as gigantothermy, which is unusual for a reptile. This thermoregulation is facilitated by their large body size, a thick layer of insulating fat, and a countercurrent heat exchange system in their flippers.
Protecting the Ocean’s Giant
The leatherback sea turtle is listed as Vulnerable globally by the IUCN, though many distinct populations, particularly in the Pacific, are Critically Endangered. It is also recognized as Endangered under the U.S. Endangered Species Act. Despite protective measures, leatherback populations continue to face significant threats.
One of the primary dangers to leatherbacks is accidental capture in fishing gear, known as bycatch, which includes entanglement in longlines and gillnets. Plastic pollution poses another serious threat, as these turtles often mistake floating plastic bags for their primary food source, jellyfish, leading to ingestion and fatal blockages. Additional pressures include illegal hunting of turtles and collection of their eggs, degradation of nesting beaches due to coastal development and artificial lighting, and vessel strikes. Given their extensive migratory routes, conservation requires international cooperation.