Sea Turtle Rescue

Solstice, a rescued endangered olive ridley sea turtle, looks out from a crate as she arrives to Tuesday, Feb. 24, 2015, in Coronado, Calif.

((AP Photo/Gregory Bull))

Think you have a tough commute? Try being a leatherback sea turtle.

Sea turtles routinely travel over 1,000 miles each year between their breeding and feeding grounds, without, for obvious biological reasons, the advantages of GPS or Google Maps. How they do so has long baffled scientists, but marine biologist Kara Dodge, of the University of Massachusetts Amherst's Large Pelagics Research Center in Gloucester, has a theory.

"These turtles might be orienting to some aspects of the earth's magnetic field, or perhaps the orientation of the sun," Dodge said. "All of this, mind you, is speculation."

Dodge and her fellow researchers, oceanographer Benjamin Galuardi and LPRC director Molly Lutcavage, tracked 15 sea turtles through their migrations over a three-year period and found they had a remarkably good nose for directions.

"I was surprised," Dodge said. "When we started getting the satellite tag data in, what was really eyebrow raising was that these paths appeared to be parallel though they were not close to each other."

Their results were published in Proceedings of the Royal Society B.

Turtles travel across expanses of open ocean, yet maintain consistent headings in the face of currents and a landmark-free route through the Atlantic. Their eyesight is poor, so star navigation is unlikely, and odor trails and currents are not likely to guide them for such long distances, Dodge said.

So, she figures, they are likely using magnetic fields and the sun's position over the horizon to navigate. Juvenile sea turtles species have demonstrated magnetic sensitivity in lab settings, along with other species like sockeye salmon and yellowfin tuna, and Dodge believes her study shows that adults may retain their compass-sense.

Helping leatherbacks maintain their sense of mystery is the difficulty in studying adults in a controlled environment. It is not known for sure whether mature turtles share the magnetic affinities of their children, and no biological mechanism has been found to explain their internal compass.

"They'll continuously swim and bash themselves against the side of the pool or tank, which makes them virtually impossible to study in a laboratory," Dodge said.

Between 2007 and 2009, the research team partnered with commercial fishers and research boats to grab and tag sea turtles with satellite recorders, in what they believe is the first migratory navigational study of adult and adolescent leatherbacks. They found that the turtles, separated by miles of ocean, followed parallel headings to their nesting beaches and winter habitats.

Dodge's research has also yielded information on the living habits of leatherbacks, which are an endangered species. Tracking results released in 2014 detailed turtle behavior in their feeding grounds off the coast of the Northeast United States, and were published in the open-access scientific journal PLOS ONE.

Dodge has a habit of naming the turtles she studies -- strictly, she says, to help her keep them straight. She named a recent batch of tagged turtles after characters from the beloved cult sitcom Arrested Development, meaning that, somewhere out in the Atlantic, George Sr. is likely snacking on a jellyfish.