Dolphins are sensitive to the presence of magnets, say researchers in France. It's the first study to definitively prove that dolphins are magnetosensitive, or magnetoreceptive.
Marine biologists at Universite de Rennes and Institut Universitaire de France exposed dolphins at the Planete Sauvage ("Wild Planet") dolphinarium, in Port-Saint-Pere, France, to a series of magnetized objects. They found dolphins swam more aggressively towards semi-submerged barrels emitting a magnetic field. Identical demagnetized barrels served as controls.
Though clearly excited by the magnetic signal, the six observed bottlenose dolphins were found to interact in equal amounts with both the magnetized and magnetized barrels, suggesting the dolphins may not be attracted the magnet signal so much as intrigued by it.
Dolphins primarily rely on echolocation to navigate the seas and to locate other animals, whether friends, enemies or prey. Scientists have surmised that dolphins also possess the ability to perceive magnetic fields. But hard evidence of such proved difficult to come by -- until now.
"Dolphins are able to discriminate between objects based on their magnetic properties, which is a prerequisite for magnetoreception-based navigation," confirmed Dorothee Kremers, who along with her colleagues at the Ethos unit of the Université de Rennes authored the recent study. "Our results provide new, experimentally obtained evidence that cetaceans have a magnetic sense, and should therefore be added to the list of magnetosensitive species."