Leatherback Sea Turtle
Copyright © 1996 Wolfgang Wuster
SCIENTIFIC NAME: Dermochelys coriacea (Linnaeus)
OTHER NAMES: Leatherback
DESCRIPTION: Largest (adults, >170 cm [5.5 ft.] straight-line carapace length; weights >500 kg [1,100 lb.]) of the sea turtles (Magnuson et al. 1990, Ernst et al. 1994). Shell unique; lacks keratinized scutes found on other sea turtles. Instead, composed of a mosaic of small bones covered with a rubbery black skin with varying degrees of pale white spots. Carapace has series of seven longitudinal ridges. Adults lack scales, and head is covered with black skin with varying degrees of pale white spots and a prominent pink spot on dorsal surface. Upper jaw has two distinct maxillary cusps. Forelimbs and hindlimbs modified into extremely long front flippers and short rear flippers, and in contrast to other sea turtles, lack claws. In adult males, tail is longer than hind flippers. Because of its unique characteristics, placed in Family Dermochelyidae, which is different from the other sea turtles; only living member of that family.
DISTRIBUTION: Widest of any sea turtle, and possibly any reptile (Ernst et al. 1994). Found worldwide in tropical and temperate waters of the Atlantic, Pacific, and Indian Oceans. Appears to be one of the most migratory of the sea turtles and is well adapted for open ocean existence. Small numbers travel as far north as British Columbia and Newfoundland, and as far south as the Cape of Good Hope, Tasmania, and Argentina. Can be found along the Atlantic and Pacific Coasts of the continental U.S., and occur throughout the Gulf of Mexico including the coast of Alabama. Normally, the only leatherback nesting in the continental United States occurs on the Atlantic Coast of Florida, but the number of these nesting females is relatively small.
HABITAT: Coastal waters, but often found in open ocean and appears well adapted to a pelagic existence. Prefers tropical nesting beaches that are relatively close to deep oceanic waters. The main nesting areas close to the continental United States are in the French Guianas and Colombia for turtles of the western Atlantic, and the Pacific Coasts of Mexico and Costa Rica for turtles of the eastern Pacific. However, a small number nest in Florida each year, the majority of which occurs along the Atlantic Coast. Occasional nesting occurs in the eastern Gulf of Mexico on the Florida Panhandle.
LIFE HISTORY AND ECOLOGY: Well adapted to life in the open ocean. Known for its deep diving capabilities, which probably relates to foraging through the deep ocean water column. Dives of more than 1,000 meters (3,280 feet) have been recorded. Well known for traveling great distances, and movements of more than 5,000 kilometers (3,100 miles) have been reported, including travel into cold waters. Most nesting occurs on tropical beaches. However, a small number nest in Florida each year during the spring and summer. Leatherback nesting beaches normally have a steep slope, have high energy wave action, and are in close proximity to deep oceanic water. A typical female will nest five to seven times per nesting season with an average of 10 days between nestings. However, some have been recorded to nest 11 times in a single nesting season. A female normally nests every other year or every third year. Lays relatively large eggs compared with other sea turtles, but produces fewer eggs per nest (approx. 60 to 90 eggs per nest). Eggs take approximately 55 to 75 days to hatch; hatchlings emerge at night and travel down to the surf. Gender of hatchlings is determined by the incubation temperature of the egg. Hatchlings will swim offshore and take up a pelagic existence. Average age to sexual maturity has not been well documented. Primarily a water-column feeder (Ernst et al. 1994). Jellyfish are a main component of the diet, but also eat other items such as squid, crustaceans, and tunicates.
BASIS FOR STATUS CLASSIFICATION: Populations have continued to decline in many areas of the world over the past two decades (Magnuson et al. 1990). Recent estimates suggest approximately 26,000 to 43,000 females nest annually worldwide, which is drastically lower than the 115,000 estimated world-wide in 1980. The population nesting on the Pacific Coast of Mexico was once considered the largest population in the world with more than 500 turtles nesting per night during the peak of the nesting season during the early to mid-1980s. However, the population declined precipitously and by the late 1990s, estimates were that fewer than 100 females nested each year (Sarti et al. 1999). Currently the largest nesting population in the world is in the western Atlantic in French Guiana, with an estimated 4,500 to 7,500 nesting females each year. During recent years, it has been estimated that approximately 35 females nest on Florida beaches annually (Ehrhart 1999). There have been no reports of nesting in Alabama. Listed as endangered by the U.S. Fish and Wildlife Service in 1970.
Author: Thane Wibbels