Animal Echolocation

Animal Echolocation

Echolocation, also called biosonar, is the biological sonar used by several kinds of animals. Echolocating animals emit calls out to the environment and listen to the echoes of those calls that return from various objects near them. They use these echoes to locate and identify the objects. Echolocation is used for navigation and for foraging (or hunting) in various environments. Some blind humans have learned to find their way using clicks produced by a device or the mouth (see Human echolocation).

Echolocating animals include some mammals and a few birds; most notably microchiropteran bats and odontocetes (toothed whales and dolphins), but also in simpler form in other groups such as shrews, one genus of megachiropteran bats (Rousettus) and two cave dwelling bird groups, the so-called cave swiftlets in the genus Aerodramus (formerly Collocalia) and the unrelated Oilbird Steatornis caripensis.

The term echolocation was coined by Donald Griffin, whose work with Robert Galambos was the first to conclusively demonstrate its existence in bats in 1938. Long before that, however, the 18th century Italian scientist Lazzaro Spallanzani had, by means of a series of elaborate experiments, concluded that bats navigate by hearing and not by vision. Echolocation in odontocetes was not properly described until two decades later, by Schevill and McBride.