Sharks can read Earth’s magnetic field like a map, study suggests

Bonnetheads – and likely other migratory species – appear to have built-in ‘polarity-based compasses’, reports Jon Sharman

Bonnethead sharks living in the Gulf of Mexico were studied to test their responses to magnetism (AFP/Getty)

Sharks are able to read the Earth’s magnetic field like a map while migrating over thousands of kilometres, a study suggests.

Researchers who experimented with bonnethead sharks found the fish responded to magnetic conditions designed to simulate those many kilometres south of their home environment by swimming “north” to correct their position.

“We know that sharks can respond to magnetic fields,” said marine policy specialist Bryan Keller, one of the authors. “We didn’t know that they detected it to use as an aid in navigation.”