A group of researchers has discovered something very interesting about sharks. The scientists discovered the first solid evidence that sharks rely on magnetic fields in their long-distance journeys across the ocean. Sharks aren’t unique in this capability; sea turtles have been long known to rely on magnetic signatures to navigate thousands of miles to the beaches where they were hatched. Until now, the team says it has been unknown how sharks manage to navigate during migration to their target locations successfully.
The new research supports the theory that sharks use Earth’s magnetic field to guide their way. Scientists have known that some shark species migrate over long distances every year to specific locations on the planet. Scientists have also known that sharks are sensitive to electromagnetic fields, and speculation has suggested that sharks use magnetic fields to navigate.
The challenge was to devise a way to test the theory in sharks. Scientists on the project say the reason the question has been a mystery for over five decades is that sharks are difficult to study. The team used a smaller species of shark known for returning to specific locations called bonnetheads (Sphyrna tiburo). The sharks migrate to the same estuaries each year, demonstrating that they knew where to navigate to from a distant location.
Researchers used magnetic displacement experiments to test 20 juvenile bonnethead sharks that were captured in the wild. They exposed sharks to magnetic conditions representing locations hundreds of kilometers away from where they were caught. Researchers predicted northward orientation in the southern magnetic field and southward orientation in the northern magnetic field. They predicted no orientation preference when sharks were exposed to the magnetic field that matched their capture site.
The scientists found out the sharks acted exactly as they predicted when exposed to fields within their natural range. Researchers say the study suggests sharks have the ability to navigate based on magnetic fields, and those fields could contribute to the population structure of sharks.