Information from Animal News Center

Loggerhead Turtles Shown to Use Magnetic Fields

by Ben Lipson

A recent study of loggerhead turtle hatchlings has revealed that

they, like many other animals, are able to follow migratory routes by

sensing Earth's magnetic fields.

"These tiny, defenseless sea turtles embark on this 8,000-mile
migration route around the Atlantic, and they do it alone without
following other turtles," said biologist Kenneth Lohmann of the
University of North Carolina, who headed the team of researchers that
conducted the study.

Eastern Florida is where the migration, which takes between five and
10 years, begins and ends. Immediately after the turtles hatch, they
dive into the Gulf Stream. The North Atlantic gyre, a circular
current that wraps around the Sargasso Sea, then takes the turtles
east across the Atlantic, past the Azore, Canary and Cape Verde
Islands, and back to Florida.

The researchers exposed hatchlings to magnetic fields that simulated
those at three locations along the migratory route - northern
Florida, the northeastern gyre near Portugal, and the southern gyre -
and recorded the directions in which the animals swam.
"We found that the turtles followed their migratory route," Lohmann
said.

The results of the study may have broad implications for wildlife
conservation efforts. If, for example, populations of a species in
different locations inherit different migratory instructions from
previous generations, then a void created when a population in one
part of the world becomes extinct may not be able to be filled with
members of a population taken from another part of the world.

"This suggests that we need to pay more attention to conserving
specific populations rather than simply focusing on species in
general," said Lohmann.

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Posted on SHARE Yahoo group Nov 22, 2001