GALVANIC
Certain animals have evolved specific sensory abilities much wider than our own...
According to Gould and Gould (1994) sensitivity to the Earth’s magnetic field as a navigational reference has evolved independently, several times, in creatures ranging from bacteria to dolphins and pigeons.
Some aquatic creatures including sharks and the platypus detect electric fields that seep through the skins of other animals. Electric eels produce their own fields and monitor distortions produced by obstacles and prey. This is analogous to echo-location in bats.
Gould, James L. and Gould, Carol Grant (1994) The Animal Mind. Scientific American Library, New York.