Leatherbacks are the largest turtles on Earth, growing up to seven
feet (two meters) long and exceeding 2,000 pounds (900 kilograms).
These reptilian relics are the only remaining representatives of a
family of turtles that traces its evolutionary roots back more than 100
million years. Once prevalent in every ocean except the Arctic and
Antarctic, the leatherback population is rapidly declining in many parts
of the world.
While all other sea turtles have hard, bony shells,
the inky-blue carapace of the leatherback is somewhat flexible and
almost rubbery to the touch. Ridges along the carapace help give it a
more hydrodynamic structure. Leatherbacks can dive to depths of 4,200
feet (1,280 meters)—deeper than any other turtle—and can stay down for
up to 85 minutes.
Leatherbacks have the widest global distribution
of all reptile species, and possibly of any vertebrate. They can be
found in the tropic and temperate waters of the Atlantic, Pacific, and
Indian Oceans,
as well as the Mediterranean Sea. Adult leatherbacks also
traverse as far north as Canada and Norway and as far south as New
Zealand and South America. Unlike their reptilian relatives,
leatherbacks are able to maintain warm body temperatures in cold water
by using a unique set of adaptations that allows them to both generate
and retain body heat. These adaptations include large body size, changes
in swimming activity and blood flow, and a thick layer of fat.
Leatherbacks
undertake the longest migrations between breeding and feeding areas of
any sea turtle, averaging 3,700 miles (6,000 kilometers) each way. After
mating at sea, females come ashore during the breeding season to nest.
The nighttime ritual involves excavating a hole in the sand, depositing
around 80 eggs, filling the nest, leaving a large, disturbed area of
sand that makes detection by predators difficult, and finally returning
to the sea.
The temperature inside the nest determines the sex of
the hatchlings. A mix of male and female hatchlings occurs when the nest
temperature is approximately 85.1 degrees Fahrenheit (29.5 degrees
Celsius), while higher temperatures produce females and cooler
temperatures produce males. Female hatchlings that make it to sea will
roam the oceans until they reach sexual maturity, when they return to
the same nesting areas to produce their own offspring. Males spend the
rest of their lives at sea.
Their lifespan is unknown but many
leatherbacks meet an early end due to human activity. It is estimated
that only about one in a thousand leatherback hatchlings survive to
adulthood. Eggs are often taken by humans from nests to be consumed for
subsistence or as aphrodisiacs. Many leatherbacks fall victim to fishing
lines and nets, or are struck by boats. Leatherbacks also can die if
they ingest floating plastic debris mistaken for their favorite food:
jellyfish. Some individuals have been found to have almost 11 pounds (5
kilograms) of plastic in their stomachs.
Leatherbacks are
currently designated as endangered under the U.S. Endangered Species
Act. The number of leatherbacks in the Atlantic appears to be stable or
increasing, but the Pacific population is declining at an alarming rate
due to egg harvest, fishery bycatch, coastal development, and highly
variable food availability. Some Pacific populations have disappeared
entirely from certain areas, such as Malaysia.
Scientists around
the world are tracking and studying leatherbacks to learn more about
these reptilian giants and how they can be saved.
Fast Facts
- Type:
- Reptile
- Diet:
- Carnivore
- Average life span in the wild:
- 45 years (est.)
- Size:
- Up to 7 ft (2 m)
- Weight:
- Up to 2,000 lbs (900 kg)
- Protection status:
- Endangered
- Did you know?
- The largest leatherback ever found was an 8.5-ft-long (2.6-m-long) male weighing 2,020 lbs (916 kg) that washed up on the west coast of Wales in 1988.
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