Sharks can read the earth's magnetic field, like a GPS, to find their way, a study released on Thursday shows.

The research, published in the journal

Current Biology

, confirms a decades-old theory about how marine predators can migrate vast distances, swim in straight lines, and return to their point of origin, explained the lead author of the study, Bryan Keller.

Scientists believe that sharks - like sea turtles and some other species - can determine their position and orientation using the magnetic field generated by our planet.

But until then there was no way to prove it.

Sharks know where 'home' is

Bryan Keller, who is project manager for the Save Our Seas foundation in Florida (United States), decided to study a small species of hammerhead shark native to the Gulf of Mexico region.

These "return to the same estuary every year," noted Bryan Keller, also a biological oceanographer at Florida State University.

“It shows that sharks know where 'home' is and can come back to it from a remote location.

"

His team collected 20 young sharks and then exposed them to a tool used to simulate the magnetic field corresponding to different places on the globe.

It is a large wooden cube with vertical and horizontal copper wiring inside, and in the center of which is a small basin containing a shark.

As expected, the sharks turned north when conditions simulated a location south of where they had been caught.

Studying the effect of human constructions

They did not move in any direction when conditions made them believe they were "at home".

According to Bryan Keller, these sharks are unlikely to be the only species to have developed this ability.

“Great white sharks, for example, migrate from South Africa to Australia, and return to the same place in South Africa every year,” he explained.

A journey over more than 20,000 kilometers, in nine months, of an animal taking "an incredibly straight path".

In the future, the researcher would like to study the effect of human constructions, such as submarine cables, on sharks.

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