Bottlenose Dolphins Can Sense Magnetic Fields
Magnetoreception is the ability to detect magnetic fields to perceive direction, altitude or location. It is basically a ‘sixth sense,’ similar to vision or hearing, in which sensory information is processed by the brain to produce a perception.
It could be detected in more than 50 species, including birds, honeybees, bumblebees, butterflies, mollusks, fish, whales, sharks, sea turtles, cows, deers, salamanders, and earthworms.
Although some observations led to the assumption that dolphins may be sensitive to magnetic fields too, compelling experimental evidence has been missing – until now.
In a new study, a group of scientists led by Dr Dorothee Kremers of the University of Rennes studied six captive-born common bottlenose dolphins (Tursiops truncatus) in the delphinarium of Planète Sauvage in Port-Saint-Père, France.
The scientists watched the animals’ spontaneous reaction to the presentation of two magnetized and demagnetized barrels, which were identical in form and density and therefore undistinguishable with echolocation.
The dolphins were free to swim in and out of the pool where the barrel was installed.
They approached the barrel much faster when it contained a strongly magnetized block than when it contained a similar not magnetized one.
“Dolphins are able to discriminate between objects based on their magnetic properties, which is a prerequisite for magnetoreception-based navigation,” Dr Kremers said.
Dorothee Kremers et al. Behavioural evidence of magnetoreception in dolphins: detection of experimental magnetic fields. Naturwissenschaften, published online September 30, 2014; doi: 10.1007/s00114-014-1231-x