Leatherback Sea Turtle (Dermochelys coriacea)
By E. G. Sebastian, Volunteer
One of the great advantages of living in the rural Lowcountry is the opportunity to encounter almost daily all kinds of wild birds and animals. It is not uncommon to see in a day’s drive several deer, a few egrets and blue herons, possums, hundreds of squirrels, turtles, occasionally armadillo, and many more. We often drive out in the weekends to different natural reserves just to observe this beautiful variety of wildlife.
One of our all time favorites are turtles. There’s just something mystical about these somewhat clumsy looking, yet so swift swimming creatures. Just recently I and my two kids – Alexa 8 and Philip 7 - tried to rescue two of them (meaning, return to water) at two separate occasions: a beautiful Box Turtle (Terrapene carolina) and an Alligator Snapping Turtle (Machrochleys temminckii) that almost bit off my hand. Luckily for the Box Turtle, I stopped at the Lowcountry Estuarium to ask where I should release it, only to learn that not all turtles live exclusively in water. But that’s the beauty of living here – there’s always something to see and learn about.
Our recent learning adventure was to find out more about one of the most amazing turtles; one that very few of us will ever have a chance to see in its natural habitat: the Leatherback Sea Turtle (Dermochelys coriacea). We learned that his turtle is so amazingly unique and different from its relatives that they had to come up with a complete separate family classification for it (Dermochelys).
The Leatherback Sea Turtle is unmistakably different from other turtles. Instead of dermal bones on the carapace as most other turtles have, the Leatherback – as its name suggests – has it back covered in a mosaic of small platelets set in a leathery skin. These little platelets are set in seven hard longitudinal ridges along the length of its back. The color of the leathery back, the limbs, and the turtle’s head is black with white spots, with a pinkish white spot on the head. They have large paddle-like limbs with no claws, with the front limbs being much larger than what one would expect from a turtle and the rear ones being broadly linked to its tail. The largest Leatherback recorded was close to 10 ft long; the average size being around 3 feet (this measured from its nose to the end of its tail).
The Leatherback is the largest living reptile in the world, with adults often exceeding 1,000 pounds, and some even exceed 2,000 pounds. It can be found in the waters around Australia all the way up close to the arctic regions, and is the reptile that can survive in the most diverse and extensive geographic areas. It can live in the colder environments due to the insulation provided by their high oil-content of their carapace (shell) combined with their capability of producing body heat by muscle activity. Satellite monitoring has showed that Leatherbacks cross entire ocean basins.
Even though Leatherbacks are considered to be an endangered species, aerial studies of the South Carolina shores have recorded more than 1,000 Leatherbacks in the past 10 years around our shores. Unfortunately, studying these mighty creatures is rather difficult due to their tendency to live exclusively in the open ocean. Most of our findings are based on females who were observed while on our shores for nesting, and the study of dead Leatherbacks washed out to the shore which provided valuable information on their feeding habits, sex, their reproductive status, and at times the cause of their death.
Most male Leatherbacks never leave the seawaters. Females leave the waters for nesting purposes, needing tropical sandy beaches with light vegetation. Females usually return to the same beach biannually or triennially, laying multiple clutches during each nesting season. The size of their clutch can vary from 40 to 160 eggs (usually around 80).
Some of their most common nesting beaches are found in Costa Rica, French Guinea, Panama, Surinam, Central and South America, several Caribbean Islands, and South Florida. Several nesting events were recorded in the past decades in South Carolina as well, at Edisto Beach State Park (Colleton County), St. Phillips Island (Beaufort County), and Huntington Beach (Georgetown County). Hilton Head Island also recently had its first documented leatherback sea turtle nest, laid on Sunday, May 7, 2006. This was the 6th recorded leatherback nesting in SC history.
Unlike most turtles, the Leatherback cannot withdraw its head into its shell, but it is protected from large predators by some strong scales on the two sides of its head.
Leatherbacks are omnivorous, eating both meet and vegetation. Their primary food source consists of jellyfish, but they also feed on crabs, fish, squid, sea urchins, blue-green algae, and seaweed.
The Leatherback’s meat is known to be toxic to humans and other animals (the Hawksbills turtle is the only other turtle with toxic meat).
All sea turtle populations are being threatened by nesting habitat destruction – they rely on the availability of mature sand dunes in which to build their nests. Adult sea turtles, as well as new hatchlings are disoriented by lights, as they rely on visual cues to find their way from the dunes to the ocean.
To reduce the chance of extinction of this amazing animal, nature preserves have been established in nesting areas. Scientists also occasionally harvest the eggs and hatch them under artificial, but safe, conditions.
E.G. Sebastian is a freelance writer and speaker. Visit him on the web at www.egsebastian.com.