Presents:
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Leatherback Turtle (Dermochelys coriacea)
Critically Endangered
Critically Endangered
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| Leatherback Hatchling |
- Average weight: Up to 900 kg (2,000 lbs)
- Average length: Up to 2 m (7 ft)
- Average lifespan: 30 - 45 years
- Range: Worldwide distribution (tropical to sub-polar oceans)
- Nests: Tropical (rarely sub-tropical)
- Diet: Carnivore – soft-bodied animals such as jellyfish and salps
About:
Leatherbacks, with the widest global distribution of all reptile species (and possibly all vertebrates), are the largest turtles on earth, and the last surviving representatives to a family able to trace their evolutionary lineage further than 100 million years in the past.
Of all sea turtles, Leatherbacks travel the longest migration routes to breed and feed, averaging 6,000 km (3,700 miles) each way. At one time these peaceful giants dominated the Arctic and Antarctic in large numbers, but over the past few decades their population has plummeted to the point of grave concern.
Found in temperate and tropical waters of the Mediterranean Sea, to the Atlantic, Pacific, and Indian Oceans, Leatherbacks are able to travel from Canada and Norway to New Zealand and South America due to their ability to generate and maintain body heat in cold waters. Large body size, a thick layer of fat (high oil content), and adjustments in both swimming activity and blood flow (thermoregulatory – counter-current heat exchange system) are adaptations that have allowed these graceful creatures to travel the various global waters.
The Leatherback shell isn’t hard and bony like other sea turtles. These reptilian relics have an inky-blue carapace [approx 4 cm (1.5 inches) thick] which is fairly flexible, making it almost rubbery to the touch. This leathery shell is filled with oil-saturated connective tissue covering loosely interlocking dermal bones, designed with seven thick, hydrodynamic, longitudinal ridges which taper to a rounded point.
They have no claws or scales on their flippers; the back ones look and act like paddles or large rudders, while the powerful front ones are quite a bit longer than found in other sea turtles. These amazing creatures can dive deeper than all other turtles, to depths of 1,280 meters (4,200 ft), and can remain submerged for up to 85 minutes.
The adults mate at sea, and then the females journey ashore for the night-time nesting rituals involving excavating a hole in the sand, depositing 80 to 100 eggs, then covering the nest before heading back out to sea. This is repeated several times during the nesting season with 8 to 12 day intervals. Sadly, the beach nesting leaves large disturbed areas of sand which allows for easy detection by predators and poachers.
Interestingly, the temperatures found within the nest will determine the sex of the hatchlings. A mix of both male and female can only occur when the temps stay within the approximate range of 29.5 degrees Celsius (85.1 degree Fahrenheit), while hotter will produce females and cooler will generate males. Surviving males will spend the rest of their lives at sea, while the females will return to the same nesting areas after reaching sexual maturity to repeat the cycle with their own offspring.
Trivia: 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.
What is their Status?
Critically Endangered (IUCN RedList)
“The main procedure for evaluating the status of sea turtles is through surveys of reproduction activity at nesting beaches. Decline in nesting has been documented to be much greater than 80% in most of the populations of the Pacific, which has been considered the species' major stronghold. In other areas of its range, the observed declines are not as severe, with some populations showing trends towards increasing or stable nesting activity. Analysis of published estimates of global population sizes (Pritchard 1982, Spotila et al. 1996), suggest a reduction of over 70% for the global population of adult females in less than one generation. The populations in the Pacific Ocean, the species’ stronghold until recently, have declined drastically in the last decade, with current annual nesting female mortalities estimated at around 30% (Sarti et. al. 1996, Spotila et al. 2000). In some areas, formerly abundant rookeries have almost disappeared. For the Atlantic Ocean, the available information demonstrates that the largest population is in the French Guyana but the trends there are unclear. Some of the Caribbean nesting populations appear to be increasing but their sizes are very small when compared to those that nested in the Pacific coasts less than 10 years ago.” (Published in 2000)
Main Threats:
Egg harvesting and illegal poaching have removed more than 95% of the clutches in some parts of the world, particularly Malaysia, taken from nests to be consumed for food or as an aphrodisiac. It’s estimated that only one in a thousand hatchlings survives to adulthood. Long-line and driftnet fishing are also serious threats, causing both adults and juvenile to be captured while on migratory routes. The killing of nesting females on beaches for oil extraction along with traditional hunts and customs are also of serious concern. Finally, oceanic pollutants, especially plastics which resemble jellyfish, their favourite food, are a significant cause of mortality, finding as much as 5 kilograms (11 lbs) of plastic in some individual turtles.
Important Pages & Info:
Free the Leatherback: http://www.freetheleatherback.com/
Vancouver Aquarium – Aqua-facts: http://www.vanaqua.org/learn/aquafacts/reptiles/leatherback-turtles
Arkive Images: http://www.arkive.org/leatherback-turtle/dermochelys-coriacea/#src=portletV3api
Note 2: This little guy is featured in one of the artworks which I'm presently working on (from The Endangered Species Series). Stay tuned for more info (and the big unveilings), but in the meantime, please have a read and ...
~ Be The Change ~
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