October 21, 2024 • Ocean Facts
Leatherback sea turtles (Dermochelys coriacea) are an ancient species that inhabit all of the world’s oceans except for the Arctic and Antarctic regions. Known for their unique, leathery shells, leatherbacks have many characteristics that set them apart from their hard-shelled sea turtle relatives. Thanks to their distinctive features, leatherbacks hold records among sea turtles in breath-holding, diving depth, migration distance, and temperature tolerance.
Despite their incredible adaptations, leatherbacks have struggled to adjust to human-caused threats. Leatherback populations around the globe are in decline, spurring many research and conservation efforts that have revealed some amazing facts about leatherback turtles.
So let’s dive in to what makes leatherbacks so special!

Leatherback turtles are unique among the seven sea turtle species in many ways. © Brian J. Hutchinson
1. Leatherbacks are Warm-Blooded
Leatherbacks are the only sea turtles that are considered warm-blooded. They rely on a unique suite of adaptations to help them maintain stable body temperatures in both cold and tropical waters. Their dark color helps them absorb heat energy from the sun, which they are able to retain thanks to both a thick adipose, or fat, layer, as well as their large body size, setting them apart from smaller turtle species that have higher surface area-to-volume ratios.
In addition, leatherbacks have a specialized blood circulation mechanism called countercurrent heat exchange in which arteries and veins are in close proximity, allowing warm arterial blood coming from the heart to heat the colder blood returning from the extremities. Conversely, to cool down, leatherbacks’ blood flows closer to the surface of the skin to expel heat, giving them a pinkish blush when they’re overheated.
2. Leatherbacks are Among the Deepest Diving Air Breathing Animals
While hard-shelled sea turtle species prefer shallow coastal waters, leatherbacks are masters of the deep, regularly diving to depths of over 1,000 meters (3,280 feet)—far deeper than most air-breathing animals. The deepest dive ever recorded by a leatherback was an astonishing 4,409 feet (1,344 meters)!
Leatherbacks can only dive to these impressive depths due to special adaptations like a compressible shell that can withstand intense pressure, oxygen management capabilities that include the ability to absorb nitrogen through their carapace thereby preventing decompression sickness, and their ability to generate and maintain a warm body temperature.

Unlike other sea turtle species, leatherbacks have 7 parallel ridges along their shells, making them more hydrodynamic swimmers. © Emilie Ledwidge / Ocean Image Bank
3. Leatherback Migrations are Among the Longest in the Animal Kingdom
Leatherback turtles embark on some of the most remarkable migrations in the animal kingdom, traveling thousands of miles and sometimes crossing entire ocean basins. These impressive animals journey from their nesting sites in tropical regions to feeding grounds in colder, nutrient-rich waters, regularly covering distances of up to 10,000 miles (16,000 kilometers) in a single migration.
The longest sea turtle migration ever recorded was made by a female leatherback from Papua, Indonesia to the coast of Oregon, U.S.A., a distance of 12,774 miles (20,558 kilometers).
Join a sea turtle volunteer trip to Trinidad with Oceanic Society and help study and protect leatherback turtles.
4. Leatherback Shells are Soft and Covered in Skin
If you touch the shell of one of the six hard-shelled sea turtle species, like a green turtle, and compare it with that of a leatherback, you’ll immediately notice an obvious difference. While a green turtle’s shell is hard and bony, the leatherback’s feels like its covered in stretched leather.
This difference is because leatherback carapaces (shells) are made of small, unfused bony pieces covered by a layer of skin, in contrast to hard-shelled turtles’ carapaces, which are made of interlocking keratin plates called scutes that cover fused ribs. The semi-bony nature of leatherback carapaces makes them flexible, allowing them to withstand the extreme pressure they experience at vast depths.
5. Leatherbacks are One of the Largest Reptiles
Leatherback turtles are the largest sea turtle species and the third largest reptile in the world (following the saltwater crocodile and the American alligator). Adult leatherbacks usually measure between 4.5 and 6+ feet (1.4-1.8 meters) in length and weigh between 600 and 1,400 pounds (300–640 kilograms).
The largest sea turtle ever reported was an adult male leatherback found in Wales that measured 6.6 feet (2 meters) long and weighed 1,980 pounds (900 kilograms).

An adult leatherback sea turtle can measure as long as 6 feet from nose to tail.
6. Leatherbacks Eat Jellyfish
Despite their massive size, leatherbacks subsist solely on gelatinous zooplankton, aka jellyfish and jelly-like organisms. It’s hard to believe that such massive creatures that make such lengthy migrations get enough nutrients from a food source comprised of 95% water, but a leatherback is estimated to consume roughly 73% of its weight in jellyfish each day!
To process their gelatinous prey, leatherbacks have spiky, keratinous papillae (resembling inward facing spikes) that line the esophagus from mouth to stomach. These spikes break down the jellies, help expel excess salt, and protect the turtle from jellyfish stinging cells called nematocysts.
Unfortunately, because jellyfish and floating plastic bags look very similar, leatherbacks and other sea turtle species often mistakenly eat plastic which can cause health and survival issues (learn more about sea turtles and plastic pollution).
7. Adult Leatherbacks Don’t Have Natural Predators
The large size of adult leatherbacks automatically excludes them as prey for most natural predators. Occasionally, a shark will take a bite out of an unlucky turtle, and, in some exceptional instances, jaguars have been known to attack nesting leatherbacks, but these instances are rare.
Because leatherbacks were not faced with high adult mortality from predators during their evolution, their populations are not adjusting well to the increased death of adult turtles from human-related threats. These include incidental catch in fishing gear, climate change, harvest and trade, pollution, and coastal development.
8. Leatherbacks Have the Largest Range of Any Reptile
Leatherbacks are considered “circumglobal,” meaning they are found in all of the world’s oceans except for the Polar regions. This widespread distribution is more extensive than any other sea turtle species, highlighting their adaptability to diverse marine environments including extreme temperatures.

While adult leatherbacks have no natural predators, hatchlings must survive birds, land mammals, and sharks before reaching adulthood. © Brian J. Hutchinson
9. Temperature Determines the Sex of Hatchlings
When leatherback turtles, like all sea turtles, lay their eggs on a sandy beach, the sex of the embryos has yet to be determined. Rather than being determined by genes, the sand temperature during incubation determines whether an embryo will develop into a male or female, a process called temperature-dependent sex determination.
With an average temperature of 29ºC (84.2ºF), a nest will hatch 50% male and female hatchlings. Anything cooler will create more male hatchlings, and warmer temperatures will produce more females.
As temperatures at many turtle nesting beaches rise due to climate change and habitat alteration, conservationists are increasingly concerned about the resulting imbalances in populations. For example, researchers at Raine Island, Australia, home to the world’s largest green turtle nesting population, estimate that 90% of turtles hatched there are female.
10. Leatherbacks are the Only Species in Their Family
The seven sea turtle species that exist today belong to a unique evolutionary lineage that dates back at least 110 million years. All seven species fall into two families: the family Dermochelyidae, of which the leatherback is the only surviving species, and the family Cheloniidae, to which the six species of hard-shelled sea turtles belong.

When leatherbacks emerge from the water to nest, they cool down as veins carrying warm blood move to the surface of the skin, appearing as a pink flush as seen on this turtle’s throat. © Ashleigh Bandimere
11. Leatherbacks Don’t Have Scales
Scaly skin is a defining feature of most reptiles, including most sea turtles, but once again leatherbacks prove to be an exception to this rule. Leatherbacks’ skin is smooth and lacks the keratinous scales that are characteristic of other sea turtles.
Instead, leatherbacks have dark skin and shells smattered with white dots, which may act as camouflage. The unique spot patterns, similar to facial scales on other sea turtle species, can be used by scientists to identify individual turtles.
Learn More About Sea Turtles
These 11 facts about leatherback turtles merely scratch the surface of our knowledge about sea turtles. To learn more about sea turtles, be sure to check out the following resources:
- Sea Turtle Facts—Explore these 11 amazing facts about sea turtles.
- Sea Turtles: The Ultimate Expert Guide—Our comprehensive guide to everything you need to know about sea turtles.
- Sea Turtle Species—Get to know each of the 7 sea turtle species with facts, photos, maps, and more.
- Sea Turtle Life Cycle—Learn all about the life cycle of sea turtles in this comprehensive overview.
- Threats to Sea Turtles—Find out why sea turtles are endangered and how you can help save sea turtles.
- Sea Turtles and Plastic Pollution—Learn all about the impact of plastic pollution and sea turtles.
