Sharks use the Earth's magnetic fields to make incredible long-distance journeys

Is there anything they can't do?

Mark Serrels
Mark Serrels Editorial Director
Mark Serrels is an award-winning Senior Editorial Director focused on all things culture. He covers TV, movies, anime, video games and whatever weird things are happening on the internet. He especially likes to write about the hardships of being a parent in the age of memes, Minecraft and Fortnite. Definitely don't follow him on Twitter.
2 min read

Sharks just became even more interesting.

Richard Grainger/University of Sydney

I'm becoming increasingly jealous of other Earth-dwelling creatures and their ability to navigate the globe using magnetic fields.

Birds use it. Bees, whales and turtles are sensitive to it. Perhaps the best use case is dogs, who might even sense the magnetic fields to figure out the best places to poop. Genius.

Now scientists have added another species to the list. Congratulations to sharks, who have officially been proven able to use magnetic fields to help them circumnavigate the globe.  

Sharks have long suspected to be part of the magnetic field club, but until now their membership has been relatively difficult to prove. The reason? Sharks are a tough species to study in general. It was known, for example, that sharks travel tremendous distances to return to very specific spots year after year. It was also known that sharks were sensitive to magnetic fields but, until now, there was no solid evidence to connect the two.

Enter the Save Our Seas Foundation and Florida State University Coastal and Marine Laboratory. 

In the journal Current Biology, researchers from the two groups reported the first solid evidence sharks use magnetic fields to navigate during their incredibly long journeys across the seas. The challenge was figuring out the best way to prove it.

"It had been unresolved how sharks managed to successfully navigate during migration to targeted locations," said project leader Bryan Keller. 

Step one: Studying smaller sharks. The team focused its studies on bonnethead sharks, active tropical sharks which weigh in at a comparatively small 5.9 kilograms (13 pounds) and travel in small groups of five to 15. 

Step two: mess with those sharks magnetic fields. Researchers exposed around 20 previously caught bonnetheads to magnetic conditions representing locations hundreds of kilometers away from where the sharks were. They then made predictions as to how that exposure might alter the shark's orientation as they attempted to recalibrate and compensate for the displacement cause by that exposure. 

The results? The sharks behaved exactly as predicted, effectively proving they use magnetic fields to navigate.

These findings, the researchers believe, partially explain some of the incredible feats pulled off by other sharks. Notoriously, one great white shark was shown to migrate between South Africa and Australia, returning to the same exact location the following year.

"How cool is it that a shark can swim 20,000 kilometers round trip in a three-dimensional ocean and get back to the same site?" Keller said. "It really is mind blowing. In a world where people use GPS to navigate almost everywhere, this ability is truly remarkable."
Considering how often my Google Maps glitches out on me, it's time to get me some of that Shark GPS.