Jellyfish are abundant in the oceans and range in size from the microscopic to giants over 5 feet across and several feet long. They drift with the ocean currents and the Leatherback turtle follows them, feeding continuously on this rich food source. Although jellyfish are largely composed of water, by eating large quantities the Leatherback can grow to an incredible size. Averaging 6 to 7 feet in length, the turtle's flippers of the same width propels it through the sea at a rapid speed. This enables the turtle to escape its only predators, the large sharks.  Generally the Leatherback turtle roams unmolested, apart from the threat of man.

The Leatherback turtle starts life as a 3-inch hatchling. Over its lifetime, the turtle will increase to 36 times its hatching size, weighing between 600 and 2,000 pounds as an adult.  Wheremale and female Leatherbacks meet in the oceans to court and mate is unknown, but every year the females gather in large numbers off steeply shelving beaches to come ashore together and lay their eggs. The beaches in the subtropics and tropics have been used for thousands of years for this purpose. A female, laden with eggs, comes ashore at night and struggles through the soft sand of the beach to nest. In one season a female Leatherback will repeat this exhausting trip between 3 to a record 13 times, digging a nest and laying eggs in the same area. The Leatherback turtle does not breed in the Mediterranean, and is only an occasional visitor there when following its primary food of jellyfish through the Gibraltar straits. 

Virtually nothing is known about the movement of this unique reptile once it has left the beach.  It is believed that the Leatherback turtle spends time in the vast seaweed mats of the Sargasso and similar seas.  It still is not known how long it takes a young turtle to reach maturity or whether the males and females reach maturity at different ages.  This will never be discovered until the turtle's movements can be traced and a means of determining age can be found. Many Leatherback turtles have scars on their heads, which may be the result of mating or fighting between males. A female returns to its nesting beach between May and July, but once a male leaves as a hatchling, it remains in the sea. There it undertakes, along with non-breeding females, the longest migration route of any living reptile, rivaling the major migrations of the whales.

The Leatherback turtle occurs in the Atlantic, Pacific and Indian oceans, remaining in the warm oceans until early spring. Then, in loose congregations, the turtles follow the gulf streams to more northern waters, feeding on jellyfish drifting with the currents.

In the vast oceans, the Leatherback turtle is rarely seen by man. Resting just beneath the surface and merging with the colour of the sea, its bluish-black carapace and head occasionally break the water's surface. It is known that the turtle occurs amongst the ice floes off Newfoundland, and the turtle has been recorded off Iceland and Norway as well. The Leatherback turtle occurs more regularly, however, in the Bay of Biscay and the southern seas of Ireland.  In certain years the ocean currents come closer to shore and the turtle can then be seen, giving a glimpse and insight into its life history.

The male and female turtles arrive in northern waters in June, but the peak occurs in August and September when the seas around the coasts of the British Isles are warmest. Before it was known that the Leatherback is warm-blooded, it was thought that these few sightings were unusual, and it was believed that the turtles died. The turtles have, however, probably been undertaking these migrations for centuries, returning via the seas off Portugal and Africa back to the Caribbean.  As man's activities threaten this vulnerable and unique animal, more must be learnt to ensure the survival of this inoffensive giant of the seas.

-- Abridged from The Leatherback Turtle: Sea Turtles and their Conservation, by Peter J. Morgan (© 1990 National Museum of Wales, Cardiff).

The World's Largest Turtle

In September 1988 the world's largest turtle was found by a member of the public on the beach beneath Harlech castle in Gwynedd, North Wales.  It was reported to the Nature Conservancy Council for Wales and transferred by one of their wardens, Mike Alexander, to the National Museum of Wales.  The specimen was a fine male, which added greatly to man's knowledge of the species.  It was transferred quickly to cold stores at -10º C to preserve its tissues; and on measurement it proved to be the largest and heaviest turtle recorded.  The turtle measured 113.5 inches (291 centimeters) in total length and 108 inches (277 centimeters) from flipper tip to flipper tip, and weighed 2,106 pounds (916 kilograms).  This specimen is now recognized as the world's largest and heaviest turtle by the Guinness Book of Records.