Question Corner: Do sharks navigate using Earth's magnetic field?

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This 2001 photo provided by Dr. Greg Skomal shows a shortfin mako shark off the coast of Massachusetts.

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Several birds and animals have been known to use magnetoreception or the special sense to detect Earth’s magnetic field to perceive the location and also track the direction during migration.

A new study published in (Current Biology) found the first solid evidence that sharks also use Earth’s magnetic fields for their long-distance travel. Sharks undergo precise, long-distance migrations and make round-trips for over 20,000 kilometres.

For the study, the team captured 20 juvenile bonnethead sharks (Sphyrna tiburo) from the Gulf of Mexico and transported them to the Florida State University lab for experimentation.

 

They exposed the animals to artificial magnetic conditions which represented locations hundreds of kilometres away from their capture location. They found that the sharks orientated themselves according to the provided artificial magnetic field.

Project leader Bryan Keller explained in a release that bonnethead sharks return to the same estuaries each year demonstrating that the sharks know where ‘home’ is and can navigate back to it from a distant location. But the question of how sharks navigate has remained unanswered for about 50 years because sharks are difficult to study, he adds.

The team has now planned to expose the sharks to magnetic fields from anthropogenic sources such as submarine cables and study their effect.