Which sea turtle has a leathery shell instead of a hard one?

The leatherback is the sea turtle with a leathery shell instead of the hard shell found in most other sea turtles.

Its scientific name, Dermochelys coriacea, means “leathery skin turtle.” Rather than having a rigid carapace covered by large keratin scutes, it has a flexible layer of skin over a network of small, bone-like structures called osteoderms. Seven ridges run along its back, helping streamline its enormous body for long-distance ocean travel.

This unusual shell is not a weakness. Flexibility helps the leatherback withstand pressure during deep dives, which can reach roughly 1,200 metres. It also supports a lifestyle spent mostly in the open ocean, where leatherbacks travel between tropical nesting beaches and cold, nutrient-rich waters. They are the largest living turtles and can reach about 2.7 metres in total length.

A common mix-up is confusing “soft shell” with no shell at all: leatherbacks still have a protective internal shell structure, but its outer covering is leathery rather than a hard, scaly surface. Hawksbill, loggerhead, and green turtles all have conventional hard shells.