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Pilot whales are cetaceans belonging to the genus ''Globicephala''. The two extant species are the long-finned pilot whale (''G. melas'') and the short-finned pilot whale (''G. macrorhynchus''). The two are not readily distinguished at sea, and analysis of the skulls is the best way to tell the difference between them. Between the two species, pilot whales range in waters nearly worldwide, with long-finned pilot whales living in cold waters and short-finned pilot whales living in tropical and subtropical waters. Pilot whales are among the largest of the oceanic dolphins, exceeded in size only by the killer whale. They and other large members of the dolphin family are also known as blackfish. Pilot whales are primarily squid eaters, but will feed on fish, as well. They are also highly social, and studies suggest that both males and females remain in their mothers' pods, an unusual trait among mammals, also found in certain killer whale communities. Short-finned pilot whales are also one of the few mammal species where females go through menopause, and postreproductive females may contribute to the survival of younger members of their pods. Pilot whales are notorious for stranding themselves on beaches, and are among the most common cetacean stranders. Several theories have been proposed to account for this behavior. The status of both species is not understood, and they have been subject to direct and indirect catches by fisheries. Whalers in a few countries continue to hunt pilot whales. ==Taxonomy and naming== Pilot whales are classified into two species: *Long-finned pilot whale (''Globicephala melas'') *Short-finned pilot whale (''Globicephala macrorhynchus''). The short-finned pilot whale was described, from skeletal materials only, by John Edward Gray in 1846. He presumed from the skeleton that the whale had a large beak. The long-finned pilot whale was first classified by Thomas Stewart Traill in 1809 as ''Delphinus melas''.〔Traill, T. S. (1809). "Description of a new species of whale, ''Delphinus melas''". In a letter from Thomas Stewart Traill, M.D. to Mr. Nicholson. ''Journal of Natural Philosophy, Chemistry, and the Arts'' 1809:81–83.〕 Its scientific name was eventually changed to ''Globicephala melaena''. Since 1986, the specific name of the long-finned pilot whale was changed to its original form ''melas''.〔Starting with: Jones Jr, J .K., Carter, D.C., Genoways, H.H., Hoffman, R.S., Rice, D.W. Jones, C. (1986) "Revised checklist of North American mammals north of Mexico", ''Occ Papers Mus Texas Tech Univ'' 107:5〕 Other species classifications have been proposed but only two have been accepted. There exist geographic forms of short-finned pilot whales off the east coast of Japan, which comprise genetically isolated stocks. Fossils of an extinct relative, ''Globicephala baereckeii'', have been found in Pleistocene deposits in Florida.〔 Another ''Globicephala'' dolphin was discovered in Pliocene strata in Tuscany, Italy, and was named ''G. eturia''.〔 The pilot whales were also close relatives of the extinct blunt-snouted dolphin. Close living relatives of the pilot whales are the melon-headed whale, the pygmy killer whale, the false killer whale, and Risso's dolphin. The animals were named "pilot whales" because pods were believed to be "piloted" by a leader.〔〔 They are also called "pothead whales" and "blackfish". The genus name is a combination of the Latin words ''globus'' ("round ball" or "globe") and ''kephale'' ("head").〔〔 ''Melas'' is Greek for "black" and ''macrorhynchus'' comes from the Greek words ''macro'' ("enlarged") and ''rhynchus'' ("snout" or "beak"). 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「pilot whale」の詳細全文を読む スポンサード リンク
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