Leatherback Sea Turtle

Overview

Dermochelys coriacea, the Leatherback Sea Turtle, is a remarkable marine reptile that represents the sole surviving member of the family Dermochelyidae, a lineage that diverged from other sea turtles over 100 million years ago. Unlike all other sea turtles, leatherbacks lack a bony shell, instead possessing a unique carapace composed of a mosaic of small bones covered by firm, rubbery skin with seven distinct longitudinal ridges. Adults can reach massive sizes, with some individuals weighing over 900 kilograms (2,000 pounds) and measuring more than 2 meters (6.5 feet) in length. Leatherbacks are truly pelagic animals, spending most of their lives in the open ocean and undertaking some of the longest migrations of any vertebrate. They possess remarkable physiological adaptations that allow them to maintain body temperatures significantly warmer than the surrounding water, enabling them to forage in frigid waters where their jellyfish prey is abundant. These turtles can dive to depths exceeding 1,200 meters (nearly 4,000 feet), deeper than any other turtle species, and can remain submerged for up to 85 minutes. The species faces severe threats across its global range, primarily from fisheries bycatch, plastic pollution (mistaking plastic bags for jellyfish), egg harvesting, and loss of nesting beaches due to coastal development and climate change. Leatherback populations have experienced catastrophic declines in the Pacific Ocean, with some nesting populations reduced by over 90% in recent decades. Conservation efforts focus on protecting nesting beaches, reducing bycatch through modified fishing gear, and international cooperation across the species' vast migratory range. Leatherbacks play a crucial ecological role as major consumers of gelatinous zooplankton, helping to control jellyfish populations in marine ecosystems. Their unique adaptations, ancient lineage, and global distribution make them a species of exceptional scientific interest and conservation concern.

How to identify

Leatherbacks are unmistakable due to their large size (averaging 1.5-2 meters carapace length) and distinctive shell structure. The carapace is dark gray to black, composed of leathery skin with seven prominent longitudinal ridges running from head to tail, and lacks the hard scutes found on other sea turtles. The head is large with a deeply notched upper jaw and lacks scales. The front flippers are exceptionally long (up to 2.7 meters span) and paddle-like without claws. Adults typically display white or pale pink spotting on the dark background, particularly on the head and flippers. The teardrop-shaped body tapers to a pointed rear end.

Habitat

Primarily pelagic, inhabiting open ocean waters from tropical to subarctic seas. Leatherbacks range from coastal waters to the deep ocean, foraging in areas with high concentrations of jellyfish and other gelatinous organisms. They regularly venture into cold temperate and subpolar waters (as cold as 0.5°C) that are inaccessible to other sea turtle species. Females return to tropical and subtropical sandy beaches for nesting.

Distribution

Circumglobal distribution across Atlantic, Pacific, and Indian Oceans. Leatherbacks have the widest distribution of any reptile, ranging from Alaska to New Zealand and from Norway to the southern tip of Africa. Major nesting areas include beaches in the West Indies, Central America, northern South America, West Africa, Malaysia, Indonesia, Papua New Guinea, and the Solomon Islands. They undertake extensive migrations between feeding grounds in temperate waters and tropical nesting beaches.

Diet

Obligate feeders on soft-bodied prey, with jellyfish comprising the bulk of their diet. Primary prey includes scyphozoan jellyfish, hydrozoans, siphonophores (including Portuguese man-o-war), salps, and pyrosomes. Adults can consume up to 73% of their body weight daily in jellyfish. They also opportunistically feed on squid, sea urchins, and fish. Leatherbacks possess backward-pointing spines in their throat and esophagus to help process slippery gelatinous prey.

Behavior

Highly migratory, with individuals traveling thousands of kilometers between foraging and nesting grounds. Leatherbacks are capable of regional endothermy, maintaining core body temperatures 18°C above ambient water through metabolic heat production, countercurrent heat exchangers, and large body mass. They exhibit deep diving behavior while foraging, with routine dives to 200-400 meters and maximum recorded depths over 1,200 meters. Unlike other sea turtles, leatherbacks are active in cold waters and have been observed feeding in subarctic regions. They are solitary except during breeding season.

Reproduction & life cycle

Females reach sexual maturity between 13-16 years (possibly up to 26 years). Nesting occurs on tropical beaches, typically at 2-3 year intervals, though annual nesting has been observed. A female may lay 5-7 clutches per season, each containing 50-170 eggs (including many smaller, infertile yolkless eggs). Incubation lasts approximately 60-70 days, with temperature determining sex (warmer temperatures produce more females). Hatchlings emerge at night, measure about 6 cm in length, and immediately head to sea. Only an estimated 1 in 1,000 hatchlings survives to adulthood.

When to look

Nesting occurs year-round globally, but individual populations have specific nesting seasons: March-July in the Caribbean and West Africa, October-March in Southeast Asia and Western Pacific. Best viewing opportunities for nesting females are during regional nesting seasons at major rookeries. They can be observed in temperate feeding grounds during summer months (May-October in Northern Hemisphere).

Cultural significance

Leatherback turtles hold significant cultural importance for many coastal indigenous communities, particularly in the Caribbean, Pacific Islands, and Southeast Asia. In some cultures, sea turtles are considered sacred or feature in creation myths. Historically, eggs and meat have been harvested for subsistence, though this practice has declined due to conservation concerns. The species serves as a flagship for marine conservation efforts globally and has inspired numerous community-based conservation programs. In some regions, eco-tourism focused on turtle nesting provides economic alternatives to egg harvesting.

Similar species

• Green Sea Turtle (Chelonia mydas)
• Loggerhead Sea Turtle (Caretta caretta)
• Olive Ridley Sea Turtle (Lepidochelys olivacea)

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