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Description, Diet and Life Cycle of Leatherback Sea Turtles
The leatherback sea turtle, Dermochelys coriacea, is an ancient species, directly descended from the first sea turtles that evolved over 100 million years ago. The largest of all turtle species, many leatherbacks exceed 8 feet in length and weigh over 2000 pounds. Rather than a hard shell, they have a flexible, leather-like carapace.
Their large size and unique circulation system help to conserve heat, and allow leatherbacks to survive in much colder water than other species of turtles. They can also dive deeper than any other reptile, having been recorded at a depth of 1230 meters (4000 feet).
In spite of their massive size, leatherbacks are graceful swimmers. Their streamlined, hydrodynamic bodies and long front flippers allow these turtles to "fly" effortlessly through the water.
Leatherbacks' diet consists mainly of jellyfish, and they have long, angled spines in their throats to keep their slippery prey from escaping. Since jellyfish eat fish larvae, leatherbacks play an important role in balancing the marine ecosystem by keeping jellyfish numbers under control and thereby preserving fish populations.
Leatherback sea turtles spend most of their lives in the open ocean. The adult males never come to shore, and the females do so only to lay their eggs. Their reproductive cycle begins in the sea, where mating takes place. The females reproduce only once every 2 to 3 years. They migrate to nesting beaches, where they dig up to 12 holes and lay around 100 eggs in each nest, covering them over with sand to protect them from predators. After 60-70 days, the eggs hatch and the hatchlings crawl to the sea.
Leatherbacks have the widest migration patterns of any turtle species, swimming thousands of miles across the Atlantic and Pacific Oceans. They have been found from the Arctic Circle to the southern tips of Africa and New Zealand, and all places in between. Females often try to return to the beaches where they were born to lay their eggs.
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Threats to Leatherback Sea Turtles
Leatherback sea turtles are on the International Union for the Conservation of Nature (IUCN) Red List as critically endangered. Once abundant, their numbers have declined dramatically in recent years. Some of the threats to leatherback sea turtles include:
- Habitat destruction- coastal development has destroyed many of the leatherbacks' nesting beaches.
- Collecting eggs- the eggs are considered a delicacy and an aphrodisiac, and have been harvested to such an extent that nesting populations have collapsed in some areas.
- Fish nets- thousands of adult leatherbacks are caught in fish nets each year and drown.
- Plastic debris- leatherbacks mistake plastic bags and other debris floating in the water for jellyfish; ingesting this material fatally obstructs their digestive systems.
- Light pollution- females are deterred from nesting on beaches with artificial lights, and hatchlings, which instinctively move toward the moonlight reflecting off the water, become confused by artificial light and may never make it to the sea.
- Natural predators- tiny hatchlings are often snatched up by birds or other predators before they even reach the water, and if they do make it to the sea, they become easy prey for predatory fish.