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Echolocation, also called bio sonar, 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 by mouth. 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''. == Early research == 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.〔Yoon, Carol Kaesuk. ("Donald R. Griffin, 88, Dies; Argued Animals Can Think" ), ''The New York Times'', November 14, 2003. Accessed July 16, 2010.〕〔D. R. Griffin (1958). ''Listening in the dark''. Yale Univ. Press, New York.〕 As Griffin and Galambos described in their book, 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. In 1912, Sir Hiram Maxim had independently proposed that bats used sound below the human auditory range to avoid obstacles. In 1920, the English physiologist Hartridge proposed instead that bats used frequencies above the range of human hearing, which ultimately proved to be the case 〔Thorpe (1958), Review of "Listening in the Dark", http://www.jstor.org/stable/1754799?origin=JSTOR-pdf〕 Echolocation in odontocetes was not properly described until two decades after Griffin and Galambos' work, by Schevill and McBride. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Animal echolocation」の詳細全文を読む スポンサード リンク
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