Turns out dolphins have a certain magnetic quality, not just figuratively but literally.

A new study published in the journal Naturwissenschaften — The Science of Nature, reveals that the aquatic mammals are attracted to magnets, behaving differently when in proximity to magnetized objects as opposed to any that are demagnitized.

Magnetoreception, or the use of magnetic fields to perceive location, direction or altitude, has been observed in several species and is theorized to play a role in the migration of dolphins, whales and porpoises. Experimental evidence to support the theory had not been gathered conclusively, however. To test the hypothesis, researchers at the Université de Rennes in France gathered six captive bottlenose dolphins and studied their reaction to different barrels. The barrels were identical physically, yet one being magnetized while the other was not:

Here, we tested the spontaneous response of six captive bottlenose dolphins to the presentation of two magnetized and demagnetized controlled devices while they were swimming freely. Dolphins approached the device with shorter latency when it contained a strongly magnetized neodymium block compared to a control demagnetized block that was identical in form and density and therefore undistinguishable with echolocation.

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