Sea turtles have an amazing way of knowing how to navigate miles and miles of ocean, and now, researchers have an even better idea of just how accurate these animals' navigation skills are.
Sea turtles have an innate ability to migrate to and from specific areas, even after being gone for a long time. They also innately optimize their routes so that they use less energy on their long journeys.
This navigation ability has long been a mystery to those studying turtles, and this particular study, led by researchers from the University of Massachusetts Amherst, is one of the first tracking the process of how turtles navigate their way through open water.
The study followed 20 adult and subadult leatherback turtles fitted with satellite recorders measuring depth of time. From 2007 to 2009, scientists tracked the turtles, following their every movement as they migrated through the western portion of the Atlantic in an area of ocean currents, a gyre, that stretches from the equator to Iceland, as well as from North America's east coast to Africa and Europe.
Even with such strong currents present, the researchers found that the trajectory of the turtles remained true as they traveled for more than 32 days with distances as long as 1,372 miles.
"We found that leatherback turtles maintain remarkably consistent compass headings in this deep, offshore realm," says marine biologist Kara Dodge. "The striking consistency of the turtles' headings throughout the gyre suggests a common orientation cue or cues."
So how do the turtles maintain such consistent headings? Although humans often use the stars for navigation, turtles have bad eyesight, so that's unlikely to help them. However, it's possible that the turtles are somehow tuned into the Earth's geomagnetic field and that assists them in maintaining their orientation. It's also possible that the turtles know how to instinctively use the position of the sun on the horizon.
While tracking the turtles, the researchers also noticed another interesting pattern.
"Migrating turtles swam directly offshore into the gyre and although they followed widely spaced paths, these paths appeared be parallel, as though they shared the same directional orientation despite being in different places at different times," says Dodge. "Understanding migratory orientation of leatherback turtles brings us one step closer to solving the mystery of how these ancient mariners navigate their watery world."
Researchers hope that future studies focus on confirming how turtles, along with other navigationally-superior ocean creatures, maintain their orientation in the deep seas and its currents.
Photo: U.S. Fish and Wildlife Service | Flickr
