New Research Reveals That Dolphins Are Sensitive To Magnetic Stimuli

Chuck Bednar for redOrbit.com – Your Universe Online
Add dolphins to the list of species that are sensitive to magnetic stimuli, as a new study published Tuesday in Naturwissenschaften – The Science of Nature revealed that the creatures alter their behavior when swimming near magnetized objects.
Lead author Dorothee Kremers of the Université de Rennes in France and her colleagues made their discovery while conducting research in the delphinarium of Planète Sauvage, and they claim their findings provide experimental behavioral evidence that marine mammals are magnetoreceptive, or capable of perceiving magnetic fields.
Magnetoreception, the study authors explain, is believed to play a key role in orientation and navigation in some species, including birds, sharks, stingrays and honeybees. While some observations of free-ranging cetacean mammals’ migration routes and stranding sites led to the assumption that creatures like dolphins, whales and purposes were sensitive to the geomagnetic field, there was little experimental evidence to support those claims.
Kremers and her co-authors tested the spontaneous response of six captive bottlenose dolphins to the presentation of two magnetized and demagnetized controlled devices while they were swimming freely. They found that the dolphins approached the device more frequently when it contained a strongly magnetized neodymium block versus a demagnetized block that was identical in form and density and undistinguishable with echolocation.
During the experimental sessions, the dolphins were able to freely swim into and out of the pool where the barrel containing the blocks was located. All six of the dolphins were studied at the same time, and each of them was able to interact with the barrel at any time during any given session with no restrictions, the investigative team said.
The individual who was given the job to place the barrels in the pool did not know whether the blocks had been magnetized or not, and the same was also true for the individual tasked with analyzing the videos of the dolphins’ reactions to the barrels.
The research revealed that the cetaceans approached the barrel much faster when it contained a strongly magnetized block than when it contained a similar nonmagnetized one. However, the dolphins interacted with both types of barrels the same way, suggesting that it was more likely that they were more intrigued by the barrel with the magnetized block than actually physically drawn to it.
“Dolphins are able to discriminate between objects based on their magnetic properties, which is a prerequisite for magnetoreception-based navigation,” Kremers explained in a statement. “Our results provide new, experimentally obtained evidence that cetaceans have a magnetic sense, and should therefore be added to the list of magnetosensitive species.”
In January 2010, neurobiologists at the University of Massachusetts Medical School (UMMS) published research associating two related photoreceptor proteins found in butterflies to animal navigation using the Earth’s magnetic field. The following month, a husband-and-wife team of neurobiologists from Frankfurt, Germany reported that iron containing short nerve branches in the upper beak of birds may serve as a magnetometer to measure the vector of the Earth’s magnetic field.
In April 2012, researchers reported in the journal Science that specific neurons in the brains of pigeons encoded the direction and intensity of the Earth´s magnetic field, which provided the birds an inborn internal global positioning system. Then earlier this year, trials conducted at the Oregon Hatchery Research Center revealed that salmon had the capability to use the magnetic field to return to the river where they were born in order to spawn as adults.

Comments

comments