The Secret of How Sea Turtles Find Their Way Home Across the OceanTakepart.com
By Katharine Gammon | 1 hour ago
Scientists have figured out how sea turtles can travel thousands of miles to return to the exact spot of their birth to lay eggs and continue the cycle of life. Now that knowledge can be put to use to better protected the imperiled animals.
The researchers have discovered that turtles most likely use the unique magnetic signature of places along the coast to guide their path.
In the new study published Thursday in the journal Current Biology, the scientists analyzed a 19-year database of endangered loggerhead nesting sites along Florida’s East Coast, the largest sea turtle breeding colony in North America. They found a strong association between the spatial distribution of turtle nests and small shifts in the Earth's magnetic field.
At certain places and times, Earth's field shifted so that the magnetic signatures of adjacent locations along the beach moved closer together. When that happened, nesting turtles packed themselves along a shorter stretch of coastline, just as the researchers had predicted. At other times, when magnetic fingerprints moved apart, sea turtles laid their eggs in nests that were fewer and farther between.
Study co-author, Kenneth Lohmann buried magnets around turtle nests and found that baby turtles who wore a nylon harnesswith a magnet attached wandered in random directions. Those that carried a brass bar were able to navigate more successfully.
Scientists are trying to figure out how exactly the sea turtles sense the magnetic fields to navigate.
“We still don’t know the physiological mechanisms behind how they’re finding the fields,” said J. Roger Brothers, a biology doctoral student at the University of North Carolina and co-author of the study. “But it seems that hatchling turtles in the egg or sometime before they leave their natal beaches are learning, and retaining that information until they are adults.”
For conservationists, the discovery can guide efforts to preserve turtles.
“Anytime you have an animal that only comes to land at select moments, knowing the reason can be helpful,” said Brothers.
One common practice is to surround the turtle nests on the beach with wire cages to protect them from raccoons or other predators looking for a snack. But those cages can distort the magnetic fields surrounding the eggs, which may interfere with the natal homing beacon that turtles are developing at the beginning of their lives.
Making these cages out of materials that don’t distort magnetic fields will be important in the future, said Brothers.
http://news.yahoo.com/secret-sea-turtles-way-home-across-ocean-220927483.html
