For years, it has been hypothesized that sharks use magnetic fields to navigate in sea but a recent study has found evidence proving a connection between electromagnetic fields and these marine animals.
Published in the latest issue of journal Current Biology on May 6, the research suggests that sharks have the ability to read Earth’s field like a map and use it to navigate through their long-distance journeys across seas.
PhD graduate and Save Our Seas Foundation project leader Bryan Keller, who conducted the research at Florida State University Coastal and Marine Laboratory told Forbesthat sharks are trained to react to unique geomagnetic signatures, hence, detect and react to variation in the magnetic field.
Despite the speculation of a mysterious magnetic sense that sharks, like other birds, sea turtles, lobsters that swim long distances exhibit, a behaviour known as ‘site fidelity’ led scientists to ask questions. In 2005, scientists had observed a white shark swim in a straight line back and forth from South Africa to Australia making them suspect that they could detect magnetic fields. Proving this, however, was harder than expected.
Keller and his colleagues carried out research to find the missing evidence of the long speculated theory. Talking to SciTechDaily, Keller said that the study supports the theory that sharks use the “Earth’s magnetic field to help them find their way, its nature’s GPS.”
They carried out magnetic displacement experiments in which they tested 20 juvenile bonnethead sharks by exposing them to different magnetic fields from locations hundreds of kilometres away –one represented Earth’s natural field where it was caught, others represented a field of locations 600 km north and 600 km south from their homes.
Bonnetheads (Sphyrna tiburo) are known to “return to the same estuaries each year” and therefore, they know where ‘home’ is and return back to it from long distances.
Watch the full video of the experiment here:
It was found that sharks changed while they moved in a random direction when subjected to the same magnetic field as from homes, they changed their course when subjected to the southern magnetic field, swimming towards north to get home.
Keller told Forbes that while the study has focused on bonnetheads and they will conduct the experiment on other shark species as well.