Next day, as the shark swam through the ring of electromagnets, Kalmijn switched the pair of electromagnets which rotated the artificial field 90 to the weaker natural field. The shark altered its course by 90 C in the same direction as the field shift. Here, at last, is a clear demonstration of magnetic orientation by a marine creature in the wild. Dozens or even hundreds of apparently healthy Pilot Whales simultaneously beach themselves and die. Certain beaches around the world are repeatedly witness to these mysterious events.
Recent evidence suggests that toothed whales have a built-in compass sense.
Earth's magnetic field causes an electric current to flow through anything moving across it which can conduct electricity. This effect is used in the construction of dynamos. In a simple dynamo, an electric current is produced in a coil of wire by rotating the coil between opposite magnetic poles. A living organism may be thought of as a bag of water throughout which various ions are distributed. When an organism moves across the Earth's magnetic field, these ions move and tiny electric currents flow in its body.