Leatherback sea turtles are the largest species of marine turtle and the only one to lack a hard shell made of scales.
Instead, these gentle giants have a softer shell made of bone and skin with seven ridges along their backs. Also unlike other sea turtles, leatherbacks do not have claws on their front flippers.
Even more unusual is that leatherbacks, unlike most reptiles, have some control over their body temperatures, making them warm-blooded. They have a thick layer of fat under their skin and a special blood supply system in their shoulders that can keep them warmer than the water around them, which means they can live both further away from the tropics and in deeper waters than other sea turtles.
Leatherback sea turtles eat mostly jellyfish, and are equipped with special spikes in their throats to keep the slimy creatures from escaping. Their jellyfish-heavy diet probably contributes to reports of leatherback turtle flesh sometimes being toxic to humans.
Like other sea turtles, leatherback turtles lay their eggs on sandy beaches, however, about 20% are “vanos,” or small, yolkless eggs that will never hatch. All the eggs in a clutch are either masculine or feminine—do you know what determines the gender of the eggs? It’s this week’s trivia question on Twitter, so if you live in the US answer now for your chance to win!
Leatherback sea turtles are classified as critically endangered by the IUCN. Threats include being entangled in fishing gear; human collection of eggs and hunting of adult turtles for meat and shell; ingestion of plastic bags, which they mistake for jellyfish; and the effects of climate change on nesting behavior and success. Atlantic populations are considered slightly healthier than Pacific populations, which have seen several important collapses since scientists began tracking sea turtles.
Oceana’s sea turtle campaign focuses on preventing sea turtle bycatch, protecting habitat, and promoting legislation that keeps turtles safe.
You can learn more about leatherback sea turtles from Oceana’s marine wildlife encyclopedia.