German zoologists have found that bottlenose dolphins are not far behind sharks and other marine animals in their ability to sense very weak electric fields, allowing them to use the Earth’s magnetic field to orient themselves in space. The scientists‘ findings were published in a paper in the Journal of Experimental Biology.
„The ability to perceive even very weak electric fields allows dolphins to find fish hidden on the seafloor under layers of sediment. Moreover, the existence of this ability in cetaceans explains why toothed whales move along the Earth’s magnetic field lines during their migrations,“ said Professor Guido Deinhardt of the University of Rostock (Germany), quoted by the journal’s press service.
A group of biologists led by Professor Deinhardt has been studying the ability of marine mammals to perceive changing and constant electric fields for more than 10 years. During this time, they have discovered the presence of this ability in two species of marine warm-blooded animals, the bottlenose dolphin (Tursiops truncatus) and the Guyana dolphin (Sotalia guianensis).
The discovery of this ability in several cetacean species has led scientists to wonder how dolphins use this sense and how developed their ability to sense electric fields is compared to sharks and other fish that also have this ability. To obtain this data, biologists created a special device that allowed them to monitor the response of two dolphins, Dolly and Donna, to an electric field. The scientists‘ measurements showed that both dolphins could detect very weak permanent magnetic fields, as low as 5 μV per cm, as well as relatively weak alternating fields (11-29 μV per cm).
According to biologists, this makes them comparable to sharks in this respect, and also allows the dolphins to sense the Earth’s magnetic field if they move fast enough through the water column. In addition, the ability to sense the electric field should help dolphins find fish in near-surface layers of sediment on the seafloor, where the work of their „echolocators“ is difficult, the researchers summarized.
Many biologists now consider dolphins to be among the most advanced mammals on Earth, rivalling higher primates in their level of intellectual development. In recent years, scientists have found much evidence that these cetaceans are capable of recognizing themselves in a mirror, using tools, transferring their skills to their relatives, coordinating their actions, and experiencing emotions previously thought to be exclusive to humans.
(cik, TASS)
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