Leatherback Sea Turtles
(Dermochelys Conacea) Los Baulus (Spanish)
- Is the largest sea turtle in the world, averaging 4 to 6 feet (125-185 cm.) in length and 550 to 1550 pounds (250-700kg). Not only is the leatherback the largest turtle in the world, but it is also the largest reptile.
- A male leatherback, found on the coast of Wales in 1988, was 9.5 feet long (about 3 meters) and weighed almost 2,000 pounds (908 kg).
- Is the only sea turtle with a soft shell. It has a leathery, oil-saturated carapace that is dark gray to black with white or pale spots.
- The widest ranging of sea turtles it inhabits nearly all the earth’s oceans and visits the shores of every continent except Antarctica.
- Feeds primarily on jellyfish.
- Nest at intervals of 2 to 3 years, though recent research has indicated they can nest every year.
- Nests between 6 to 9 times per season, with an average of 10 days between nesting.
- Does not necessarily return to a natal beach to nest, but does return to a range area.
- Is in extreme danger of extinction. Primary causes for this are commercial fishing, egg harvesting, coastal development and environmental degradation
Unlike Any Other Turtle
Unique among sea turtles, the Leatherback is perhaps, the most mysterious of its order. Mostly pelagic, the Leatherback spends so much of its life in the deep ocean that it is difficult for researchers to know its sea-going habits. They are the widest ranging of all sea turtles, migrating thousands of miles in open waters. Their streamlined bodies and powerful front flippers evolved for distance swimming.
This global aquatic traveler inhabits three of the earths four oceans, visiting the shores of five out of six continents. The Leatherback visits these shores only briefly, and for the singular purpose of nesting. Its unique ability to regulate its internal temperature enables it to inhabit much colder waters than other sea turtles. It is common for Leatherbacks to dive 3000 feet; they have also been observed diving to frigid depths of nearly 5000 feet.
The Leatherback is the only sea turtle with a soft carapace. This leathery hide, (ala the name) is extremely oily. In fact, the leatherback is oily right down to the very bones. The carapace has seven distinct ridges running lengthwise.
On average, the Leatherback turtles in the Caribbean grow larger than those found in other locations.
Magnetic Fields Influence Migration of Leatherbacks
There has been extensive research conducted regarding the sea turtles’ abilities to return to their nesting regions and sometimes exact locations from hundreds of miles away. In the water, their path is greatly affected by powerful currents. Despite their limited vision, and lack of landmarks in the open water, turtles are able to retrace their migratory paths. Some explanations of this phenomenon have found that sea turtles can detect the angle and intensity of the earth’s magnetic fields.
The Reproductive Cycle and Nesting
Courtship and mating occur during a brief window of time when the female is receptive. Females mate with several males before nesting and store the sperm in their bodies for several months. This behavior allows for the greatest genetic diversity within the species.
When the female Leatherback is ready to nest, she will choose a beach without a coral reef, one close to the deep water. Crawling up from the ocean, she will locate a dry area and begin the arduous task of nest excavation. Using her flippers and the rotation of her body, she will dig an egg cavity that is approximately 70 centimeters deep. She will then lay 80 to 100 eggs, a process that can take over two hours. Eggs are often referred to as the size of billiard balls: she lays an average of 80 fertilized eggs and 30 smaller, unfertilized eggs in each nest. After she is finished, she will carefully cover and camouflage the clutch, and may even construct false nests to fool predators. Her role now complete, she will depart to the ocean, leaving her eggs to their fate.
Hatchlings emerge in 60 –65 days, depending on sand temperature, which also determines the sex of the hatchling. They crack their shells open by using their "caruncle", a temporary, sharp egg tooth, which falls off after birth. Struggling up from the bottom of the nest to the sand’s surface, emergence entails an ordeal that can last a few days. Because hatching takes place beneath the sand, emergence from the shell is never observed under natural conditions. Not all eggs hatch and not all hatchlings make it to the surface. Those that do emerge successfully may not survive the trek from nest to the ocean. Predators, scorching midday heat, obstacles, both natural and manmade will thwart their journey. In fact, only one in a thousand hatchlings will make it through the perilous journey to adulthood.
Leatherbacks are in immanent danger of extinction. A critical factor (among others) is the harvesting of eggs from nests. Valued as a food delicacy, Leatherback eggs are falsely touted to have aphrodisiacal properties in some cultures. The leatherback, unlike the Green Sea turtle, is not often killed for its meat; however, the increase in human populations coupled with the growing black market trade has escalated their egg depletion. Other critical factors causing the leatherbacks’ decline are pollution such as plastics (leatherbacks eat this debris thinking it is jellyfish; fishing practices such as longline fishing and gill nets, and development on habitat areas. Scientists have estimated that there are only about 35,000 Leatherback turtles in the world.
Leatherback’s Role in the Ecosystem
We are often unable to understand the critical impact a species has on the environment—that is, until that species becomes extinct. Even if we do not know the role a creature plays in the health of the environment, past lessons have taught us enough to know that every animal and plant is one important link in the integral chain of nature.
Some scientists now speculate that the Leatherback may play an important role in the recovery of diminishing fish populations. Since the Leatherback consumes its weight in jellyfish per day, it helps to keep Jellyfish populations in check. Jellyfish consume large quantities of fish larvae. The rapid decline in Leatherback populations over the last 50 years has been accompanied by a significant increase in jellyfish and a marked decrease in fish in our oceans.
Saving sea turtles is an International endeavor. Save The Turtles, Inc. is proud to be among the many respected organizations fighting for the survival of the Leatherbacks.
We gratefully appreciate the following resources we have used in compiling some of our information:
Caribbean Conservation Corporation: http://www.cccturtle.org
Everything you want to know about sea turtles: satellite tracking of turtles' migration, scientific reports from leading biologists, newsletters.
Scott A. Eckert PhD: Testimonial to the US Commission on Ocean Policy: May 2002.
Sea Turtle Restoration Project: We urge you to check out this site, especially on the top left side, the activists’ corner. Robert Ovetz Ph.D and team have rallied the United Nations for safer fishing practices. There is a great deal we can do to save sea turtles! http://www.seaturtles.org
Great resource including a marine newsletter and photo library: http://www.seaturtle.org
Annual Symposium On Sea Turtle Biology and Conservation, Philadelphia, USA
Troeng, Sebastian (CCC), D Chacon (ANAI), B. Dick (Pacuare):
Playa Grande in Costa Rica: http://www.leatherback.org