Leatherback Sea Turtles

How turtles can conquer Atlantic by swimming thousands of miles in a perfectly straight line

By David Derbyshire
Last updated at 11:27 AM on 5th January 2011

They are famed for their epic voyages across the world's roughest oceans.

But until now, nobody quite appreciated just how good leatherback turtles were at navigation.

In a new study, British scientists have discovered that the gigantic females can swim for thousands of miles in a perfectly straight line.

Following a course that would be the envy of a state-of-the-art cruise liner, the turtles make the transatlantic journey from Central Africa to South America using the shortest possible route.

Exactly how turtles can swim in a straight line remains a mystery to biologists.

However, they are thought to use a combination of vision - relying on the position of the stars and sun - and a sense of the Earth's magnetic field, to steer their way.

The findings come from a study led by the Centre for Ecology and Conservation at Exeter University.

Over five years, the researchers tagged 25 females with satellite tracking devices strapped or drilled to their shells as they left their hatching grounds in Africa to seek food across the Atlantic.

They discovered three migratory routes - including one 4,699 mile journey straight across the Atlantic from Gabon to the coastal waters off southern Brazil and Uruguay that took 150 days.

Are we there yet? Leatherback sea turtles travel thousands of miles for anything up to 150 days to reach feeding and breading grounds

Scientists from Exeter University have now discovered that these amazing creatures are able to make their long journeys traveling the shortest possible route - often swimming in a perfectly straight line

Fancy a dip? Leatherbacks spend almost their entire lives in the water. The only time they leave their watery sanctuary is when they are nesting or when hatchlings, like this little fella, emerge from their nests

A map of the three routes taken by migrating turtles. Group 2, made up of leatherback turtles, travelled in a straight line

LEATHERBACK FACT FILE

• Leatherbacks can live up to 60 years.
• They grow up to 6.5ft and weigh more than half a ton.
• It's shell is made from thick leathery skin and has the texture of rubber.
• On migrations, they swim 30 miles a day - reaching speeds of 22mph.
• Their main source of food is jellyfish, although they also eat squid and sea urchins.
• They mistake shopping bags for jellyfish and more than half of dead turtles have plastic in their stomachs.
• They can stop their blood flowing into their flippers to keep their bodies warm.
• After spending their childhood at sea, the females return to the same beaches where they hatched to lay eggs.
• Turtle eggs are used in traditional Asian medicine and in the tropics for food. In Latin America they are regarded as an aphrodisiac.
• They are hunted for food, for their shells and to be rendered into oil..
• They only time they are on land is when they lay eggs - and when hatchlings emerge from the nest.