Giants

• Leatherback sea turtles are the largest living turtle species on Earth today. Weighing up to 2,000 pounds and stretching up to 8 feet in length, their massive bodies travel the entire ocean in search of food and breeding grounds. The leatherbacks have roots that go back 100 million years and the turtles once roamed the oceans in the hundreds of thousands. Now, however, leatherback sea turtles on endangered species lists across the world.
  
  

On Land

• On land, leatherbacks move slowly. Dragging their massive bodies with their front fins, every inch forward is a laborious undertaking with immense exertion. Females search out the nesting sites of their birth and often lay up to 100 eggs in one sitting. Once the hatchlings emerge, they drag their 1 to 2 inch bodies straight for the water, relying totally on instinct.
  
  

In Water

• Though slow and awkward on land, leatherback sea turtles are graceful in open water. In an interview with "National Geographic" magazine, Scott Eckert of the Wider Caribbean Sea Turtle Conservation Network at Duke University said, "This is one of the finest hydrodynamically designed animals on the planet. They can probably swim as easily as rest."
  Like all turtles, leatherbacks flap their front flippers vertically to generate thrust and forward motion. But unlike others who rely on a constant paddling motion, leatherbacks use their long, front flippers exclusively as wings generating underwater flight.
  Their shells also are specially designed for flexibility and efficiency. Unlike the overhanging shells of other species, leatherbacks' flexible, form-fitting carapace merges perfectly with its muscular shoulders. It has seven special ridges running the length of its shell which assist in directing water flow and reducing drag.
  Leatherback sea turtles are also experts at using and conserving energy. Their large size, accompanied by a thick layer of fat, keeps them warm in cold temperatures where they hunt for their favorite food, enormous jellyfish such as the lion's mane. The blood flow to and from their large flippers also changes in colder depths. Blood returning to the body core from outer appendages is warmed by outgoing blood. In extremely cold temperatures, blood flow to and from the flipper surface may shut down entirely for a period of time.
  
  

Conservation

• Leatherbacks are known to dive to depths of 4,200 feet to feed on prey. They won the 1992 Guinness Book of World Records title of fastest reptile, having reached speeds of up to 9.8 meters per second. Leatherback sea turtles, however, are on a frightful decline, particularly in the Pacific. Once they reach adolescence, these huge animals have no predators and are threatened only by human activity. Habitat destruction, fishing nets, global warming and pollution are all threats to leatherbacks. Fortunately, many turtle advocates recognize the magnificence of these creatures and have started successful conservation projects worldwide.