Dolphins are often regarded as the smartest animals in the ocean, with remarkable cognitive skills for an animal that chooses to live in the water despite needing to breath fresh air. Now, scientists at the Université de Rennes in France have found another “super power” of sorts to go along with the sonar they use to find prey: Magnetosensitivity, or the ability to sense and react to magnetic fields.

“Dolphins are able to discriminate between objects based on their magnetic properties, which is a prerequisite for magnetoreception-based navigation,” says lead researcher Dorothee Kremers. “Our results provide new, experimentally obtained evidence that cetaceans have a magenetic sense, and should therefore be added to the list of magnetosensitive species.”

In the study, dolphins demonstrated clearly different behavioral patterns when in the presence of magnetized objects. There’s little research into magnetosensitivity among cetaceans like dolphins, so Kremers and her team set up four pools at the Planète Sauvage in Port-Saint-Père to study six bottlenose dolphins. The pools were identical save for a barrel in each, some of which contained strongly magnetized blocks while others didn’t. The magnets were the only variable, making all four pools indistinguishable as far as the dolphins’ echolocation was concerned.

Though the dolphins showed interest in the barrels regardless of whether they were magnetized (as they were the only objects of interest in the pools), the team’s analysis of their behavior showed that they gravitated towards the magnetized barrels much faster than the non-magnetized ones. This suggests the magnetic field may have been more of an item of interest than a compelling force.

It’s long been suspected that cetaceans and other free-roaming ocean species use Earth’s magnetic field as a means of orientation and navigation. Kremers’ research becomes yet another small piece of the puzzle seeking to eventually determine exactly how such mechanisms work.