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Reese Halter's Blog


Story ran on Malibu Times Blog March 8, 2013

Sea turtles are ancient but not primitive. Having evolved on land some 200 million years ago, they spend their entire lives at sea except to lay eggs on rugged beaches around the globe.

Leatherback turtles are the largest of the seven sea-faring species and they are truly remarkable, most worthy of admiration and in dire need of protection.

Leatherbacks are Earth’s last giant warm-blooded reptiles; their weight can easily exceed one ton.

All sea turtles except leatherbacks have shells. Leatherbacks instead have backs with a jigsaw of thousands of small, thin bones overlaid by a thick matrix of oily fat and fibrous tissue. Their belly has only a narrow oval bone with heavy fibrous tissues.

They are the fastest-growing and heaviest reptiles in nature. And the fastest swimming turtle with the widest distribution.

Their four legs are wings in the sea and shovels on the beach.

Leatherbacks live in both the Atlantic and Pacific Oceans.

Atlantic leatherback’s nest every other year with clutches of about 85 eggs. Pacific leatherbacks nest every fourth year and only produce clutch sizes of approximately 65 eggs.

After the female digs the nest, she fills the chamber with eggs, but the first couple dozen are yokeless. It is thought that these first eggs provide air spaces at the top of the nest, stabilize humidity, protect against fungus and insects, and after two months of incubation provide “elbow-room” for the unusually long-winged hatchlings.

A hatchling will grow 30 times its size and add 6,000-fold in weight. They generally mature by the age of 12 and live in the wild for almost 60 years.

Leatherbacks born in Trinidad, St. Croix, Costa Rica, French Guiana, Florida and South Carolina travel north to the icy waters of Cape Breton, Nova Scotia. They have adapted to these frigid conditions with bones that are tipped with cartilage packed with blood vessels rich in nutrients—a trait common in mammals.

Leatherbacks gorge themselves on seven-foot-wide, stinging lion’s mane and moon jellyfish. Extremely long esophagi enable each leatherback to consume about three-dozen jellies a day.

From Cape Breton they journey thousands of miles to the shores of Spain or North Africa before returning to breed in the southeastern Atlantic.

Leatherbacks are also the deepest deep-sea divers on the globe. Their incredible high red blood-cell density allows them to out-dive even sperm whales as they forage almost a mile beneath the surface.

Leatherbacks have the widest distribution of any animal in nature except some great whales.

Populations of leatherbacks in the Pacific travel an astounding 6,800 miles from Japan (and a small fraction from Australia) to Baja, Mexico, or from New Guinea to western Costa Rica. Populations stay for a couple decades off their migratory shores before swimming across the Pacific to breed.

One hundred years ago there were a couple billion, today there are about 35,000 female leatherbacks left on the globe.

Each year approximately 1.4 billion hooks from commercial fisheries are set into the oceans. Longlines are fishing lines up to 60 miles, dangling thousands of baited hooks; as many as 10 leatherbacks have been caught in a single set of a line.

Egg poachers have also annihilated leatherback populations.

If allowed to breed, leatherback populations will slowly rebound. They have survived on Earth for over 100 million years: Support their protection by stopping ‘The War Against Nature.’

Australia, Radio 1, National: Ockham’s Razor

Earth Dr Reese Halter is an award-winning broadcaster and distinguished conservation biologist. His latest book with Chris Maser is Life, The Wonder of it All

Contact Earth Dr Reese Halter

Text © by Dr Reese Halter 2013. All rights reserved.

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