Scientists have now worked out how sea turtles return to the beach where they were born to lay their own eggs.
Despite the fact that they migrate over thousands of miles, sea turtles always manage to return to their place of birth, a fact which has puzzled scientists for over 50 years. Now a new study has revealed that they use the Earth’s magnetic field to guide themselves home to nest.
Sea Turtles use Earth’s geomagnetic field
The study has found that the so-called geomagnetic imprinting hypothesis best explains how the sea turtles accurately navigate such long distances. The research was undertaken by scientists at the University of North Carolina, who studied Florida sea turtles and measured changes in the Earth’s magnetic field for a period of almost 20 years.
The idea was to work out whether turtle nesting locations changed in accordance with the magnetic signatures of the Earth, and the scientists discovered that there was a strong correlation between the two variables.
When the Earth’s magnetic field changed, the turtle nests were found to be more tightly packed. In locations where the magnetic signatures diverged, there were fewer nests, and they were further apart.
“Our results provide evidence that turtles imprint on the unique magnetic field of their natal beach as hatchlings, and then use this information to return as adults,” study co-author J. Roger Brothers said.
He later added that scientists are still looking for an explanation as to how the turtles detect the geomagnetic field. One possible explanation is the existence of tiny magnetic particles in their brains, which enable them to process the signature of the magnetic fields.
“Presumably that’s the same or might be the same material we use in compass fields. But there is no conclusive evidence either way,” he claimed.
What we do know is that turtles appear to work on the basis that if a beach provided favorable conditions for them, it should also provide a safe hatching site for their own offspring.