Blue Zoo: Leatherback Sea Turtle
The leatherback sea turtle (Dermochelys coriacea) is an animal of extremes. The largest of the sea turtles, they can reach 2,019 pounds (916 kg), and the species comes from a different lineage than the other sea turtles alive today.
Photo by US Fish and Wildlife Service via Wikimedia Commons, Public Domain.
While other turtle species have a hard shell completely fused around the outside of their body for protection, the leatherback’s shell is flexible and is covered in a layer of fat and skin.
On the left is the skeleton of a leatherback sea turtle, whose ribs are not fully fused. For comparison, on the right is a loggerhead sea turtle, whose shell is more complete.
As a reptile, you would expect the leatherback to be cold-blooded, but here it is also different from the norm! Because of its layer of fat, and its large size, the leatherback sea turtle is so well insulated that when it swims it generates enough heat to keep its body temperature above the temperature of the surrounding water! This means that, while other sea turtles are confined to warm tropical waters, the leatherback can travel into cooler temperate areas – such as off the coast of California – where the waters are rich in nutrients and full of their favorite food, jellies.
Leatherbacks are very specialized to eat jellies. They have downward facing spikes inside their mouths and all the way down their esophagus. These help to keep the slimy and slippery prey inside.
Photo by Scott Benson, NMFS via Wikimedia Commons, Public Domain.
The leatherback is also the deepest diver of all the reptiles and has been recorded reaching depths of 4,100 feet (1250 m). It can do this in part because of its warm body, which allows it to survive the cold deep waters. Another important factor is its flexible shell, which is just flexible enough to compress under the pressure during deep dives.
Even though the leatherback can feed in cold, temperate waters, for mating and laying eggs, it has to be in warm environments – so leatherbacks make extremely long migrations between their breeding and feeding grounds. One turtle was recorded traveling 12,774 miles (20,558 km) over the course of less than 2 years!
When they’re in the tropical mating habitat, the female leatherbacks crawl up on shore to dig a hole in the sand on the beach. They lay their eggs and bury them and return to the sea. They do this several times during mating season, leaving multiple clutches of eggs. The eggs incubate in the sand until they’re ready to hatch when the baby turtles crawl out of the sand and scurry down the beach to the ocean. Scientists still know almost nothing about what the young turtles do while they are maturing out at sea; this time of their life cycle is called ‘the lost years.’
A tiny baby leatherback makes its way from its nest to the sea as soon as it hatches. Photo by jimmyweee via flickr, Creative Commons License.
Different leatherback populations occur in different regions. There is a population in the Atlantic Ocean that is currently starting to recover from near-extinction. However the Pacific Ocean populations are not so lucky, and have faced a serious decline over recent decades. Both the East Pacific (which nest in central America) and West Pacific (which nest in and around Indonesia) populations are considered critically endangered.
Leatherbacks face many threats both in the sea and on land. Between the risk of becoming bycatch in a fishing net in the open ocean, choking on a plastic bag that looked a lot like a tasty jellyfish, illegal poaching of sea turtle eggs on the beach, and problems resulting from climate change (such as sea level rise shrinking nesting beaches), leatherbacks have a lot of dangers to face and need a lot of help getting back on the path to recovery.
Our film crew used red lights to film the Leatherback mother, because turtles cannot see red light.
Some of the ways you can help are by raising awareness of sea turtle threats, and supporting efforts to protect sea turtles both at sea and on the nesting beaches. If you live near a turtle beach, you can volunteer for organizations that take action to protect the nesting habitat from various threats.
For more information and more ways to help check out our infographic here. You can also learn more about these incredible reptiles and see them on the giant screen in our new film, Journey to the South Pacific, an IMAX Entertainment and MacGillivray Freeman Films presentation, out in select IMAX theatres November 27.