A leatherback turtle. A new study suggests the animals, which have been known to use the planet’s magnetic field to navigate as hatchlings, may use it in adulthood, too. Credit Kara Dodge. Leatherback turtles can travel thousands of miles through the ocean each year. Yet when females are ready to nest, they somehow manage to return to the same beach again and again.
Some studies have indicated that their palm-size hatchlings orient themselves to Earth’s magnetic field. A study published in The Proceedings of the Royal Society B finds that the turtles may use the field to navigate in adulthood, too.
Scientists at the National Oceanic and Atmospheric Administration tracked 15 leatherback turtles with GPS tags from August 2007 to September 2009. The turtles swam from their feeding grounds off the coast of Massachusetts to the western Atlantic subtropical gyre, a great swirl of ocean currents circulating from the Equator almost to Iceland and from the East Coast to Europe and Africa.
The researchers found that despite being in the currents, the turtles were able to keep moving south.
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“They were able to maintain their orientation during day and night,” said Kara Dodge, an N.O.A.A. marine biologist in Woods Hole, Mass., and an author of the new paper. “This suggests they are using the Earth’s magnetic field.” Dr. Dodge conducted the research as a doctoral student at the University of Massachusetts Amherst.
Adult leatherbacks do not survive in captivity. But research on the sensory systems of turtles that fare better in the lab, like loggerheads and green sea turtles, may reveal more about their navigational skills.