October 15, 2016

Leatherback Sea Turtle

Posted by: Jeanne Christie

Leatherback Sea Turtle
Adult leatherback. Photo: Virginia Herpetological Society

The leatherback sea turtle (Dermochelys coriacea) is the largest of the world’s seven species of sea turtles, and in terms of weight is the largest reptile on the planet as well. This impressive animal can reach 6 feet in length and weigh 900-1,000 pounds, with the largest leatherback ever recorded tipping the scale at over 2,000 pounds.

While the most common nesting sea turtle on the Georgia coast is the loggerhead, leatherbacks have nested on nearby islands a few times over the years. Blackbeard, Cumberland, Jekyll, Ossabaw, Sea Island, St. Catherines, St. Simons, and Sapelo have all had leatherback nests in the past five years.

To add to their list of superlatives, leatherbacks are the most widely ranging sea turtle in the world. Leatherbacks’ major nesting sites are in the Caribbean, Central and South America, Africa, southeastern Asia, and the South Pacific Islands, but their migrations can take them over 3,000 miles from their nesting grounds each year.

Leatherback hatchling. Photo: Laura Early

The leatherback’s diet consists mainly of jellyfish and other soft-bodied invertebrates, and because of special adaptations, leatherbacks are able to follow their food sources into much more frigid waters than other turtles are able to tolerate. A countercurrent heat exchange system and layers of fat help leatherbacks retain a warmer body temperature in cold waters. Special adaptations in their lungs also enable leatherbacks to dive deeper than any other turtle and most marine mammals—as deep as 4,000 feet, and these dives can last for up to 85 minutes.

The unique nature of their carapace also helps the leatherback complete these long, deep dives. Unlike other sea turtles, the leatherback’s ribs and vertebrae are not fused to create a rigid shell, but instead are integrated into a cartilaginous layer. The layer of skin covering the matrix of bones and cartilage gives the turtle flexibility, hydrodynamics and protection in addition to its common name.

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