Animal echolocation in the external ear. There are two hypotheses about the evolution of echolocation in bats. The first suggests that laryngeal echolocation evolved twice in Chiroptera, once in the Yangochiroptera and once in the horseshoe bats (Rhinolophidae). The second proposes that laryngeal echolocation had a single origin in Chiroptera, was subsequently lost in the family Pteropodidae (all megabats), and later evolved as a system of tongue-clicking in the genus "Rousettus". Individual bat species echolocate within specific frequency ranges that suit their environment and prey types. This has sometimes been used by researchers to identify bats flying in an area simply by
Animal echolocation 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 the American zoologist Donald Griffin, whose work with Robert Galambos was the first to convincingly demonstrate its existence in bats in 1938. As Griffin described in his book, the 18th century Italian scientist Lazzaro Spallanzani had, by means of a series of elaborate experiments, concluded that when bats fly at night, they rely on some sense besides vision, but he did not discover that the other sense was hearing. The Swiss physician and