The largest turtle on Earth has no hard shell, keeps itself warm in cold water and dives deeper than most whales. Its East Pacific population, which nests in Mexico, is one of the most endangered sea turtle populations in the world.
Huge, with a black, leathery back speckled with white and seven long ridges running from head to tail; there are no scutes or hard plates. The front flippers are very long, the underside is pinkish-white, and many have a pink spot on top of the head.
Leatherbacks live in every ocean. The East Pacific population nests on beaches in Mexico and Central America from October to March, peaking in December and January. In Mexico the key beaches are Mexiquillo (Michoacán), Tierra Colorada (Guerrero), and Cahuitán and Barra de la Cruz (Oaxaca); CONANP lists Todos Santos and Agua Blanca in Baja California Sur as secondary nesting beaches. On Mexico’s Pacific coast a female lays about five clutches a season, roughly ten days apart, averaging about 62 eggs each, and the eggs hatch in about 60 days.
They feed on soft, gelatinous animals such as jellyfish and salps, which they grab with sharp-edged jaws. Some swim more than 10,000 miles (16,000 km) a year between nesting and feeding areas. They mature at 9 to 20 years. Nesting counts in Mexico and Central America have fallen more than 90% since the 1980s, mainly because of bycatch in fisheries and egg poaching; by 2011–2015 only about 176 females a year were nesting across Mexico, Nicaragua and Costa Rica.
Leatherbacks have been measured at 25.5 °C in 7.5 °C seawater. Researchers called it gigantothermy: a huge body, insulating fat and special blood circulation hold the heat in. They suggested big dinosaurs may have stayed warm the same way.
Source ↗The deepest recorded leatherback dive is nearly 4,000 ft (about 1,200 m), and they can stay down for up to 85 minutes.
Source ↗The largest leatherback ever recorded washed up at Harlech, Wales, in 1988: 916 kg and 2.56 m along the shell. It had drowned, and a compacted piece of plastic was blocking its intestine.
Source ↗Satellite tags on 46 females that nested at Playa Grande, Costa Rica, showed them leaving along the same narrow corridor every year, past the Galápagos and on to the South Pacific.
Source ↗Many leatherbacks have a pink spot on top of the head whose shape is different in each turtle, so researchers can use it to recognize individuals.
Source ↗In late December 2024 a leatherback laid about 80 eggs on a beach in Cabo San Lucas Bay, the first leatherback nest there since 2010. Local turtle protectors moved the eggs to an incubation area to protect them.
Source ↗Seeing a leatherback at sea off Cabo is a rare event. The nearest regular nesting beaches are on Mexico’s mainland Pacific coast, but a few females nest in Baja California Sur between October and March: Los Cabos programs protected leatherback nests on the Pacific beaches in December 2021, in Cabo San Lucas Bay in December 2024 and at La Ribera on the East Cape in November 2025. If you spot one, slow down, keep your distance and let it go its way.
If a leatherback gets hooked or tangled in a line, don’t try to bring it aboard: never lift it out of the water by the line and never use a gaff. Move the boat slowly toward it, keep the line from jerking, take off any line wrapped around it, and if the hook can’t be removed safely, cut the line as close to the hook as possible. Every sea turtle caught by accident must go back to the sea by law; report the encounter to PROFEPA.
| Mexico (NOM-059-SEMARNAT-2010) | In danger of extinction (P) |
|---|---|
| Total ban (DOF, May 31, 1990) | Total, indefinite ban: capturing, chasing or disturbing sea turtles and taking their eggs is prohibited; turtles caught by accident must be returned to the sea |
| Federal Penal Code, art. 420 | 1 to 9 years in prison and 300 to 3,000 days’ fine for capturing, harming or killing a sea turtle or taking its products; up to 3 more years in protected areas or for commercial ends |
| Nesting beaches (NOM-162-SEMARNAT-2012) | No vehicles on nesting beaches in season except monitoring and protection work; lights must not shine on the beach |
| IUCN Red List | Vulnerable globally (2013); East Pacific subpopulation Critically Endangered (2013) |
| CITES | Appendix I (international commercial trade banned) |
The East Pacific population has dropped more than 90% since the 1980s and loses about 15% a year. A 2020 study projected it would disappear in less than 60 years unless adult survival, cut mostly by fishing bycatch, improves by at least 20%.
Every other sea turtle has a hard shell made of plates (scutes) and is far smaller. The olive ridley (golfina), which nests on Los Cabos beaches, has a rounded gray-green shell.
Rarely. A leatherback nested in Cabo San Lucas Bay in December 2024, the first there since 2010, and a few other nests have been found in Los Cabos and the East Cape. Nesting runs from October to March.
It’s possible but rare. If you do, slow down and keep your distance; it’s illegal to chase or disturb any sea turtle in Mexico.
Mainly accidental capture in fisheries and egg poaching. Nesting in Mexico and Central America has fallen more than 90% since the 1980s, and the subpopulation is listed as Critically Endangered.
Top illustration: Top Anglers. Photos: iNaturalist contributors, credited on each photo.
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