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| unranked_subordo = Cetacea | unranked_superfamilia = Mysticeti | familia = Eschrichtiidae | genus = ''Eschrichtius'' | genus_authority = Gray, 1864 | species = ''E. robustus'' | binomial = ''Eschrichtius robustus'' | binomial_authority = Lilljeborg, 1861 | range_map = Cypron-Range Eschrichtius robustus.svg | range_map_caption = Gray whale range | synonyms = *''Balaena gibbosa'' Erxleben, 1777 *''Agaphelus glaucus'' Cope, 1868 *''Rhachianectes glaucus'' Cope, 1869 *''Eschrichtius gibbosus'' Van Deinse & Junge, 1937 *''E. glaucus'' Maher, 1961 }} The gray whale (''Eschrichtius robustus'') is a baleen whale that migrates between feeding and breeding grounds yearly. It reaches a length of , a weight of , and lives between 55 and 70 years.〔(Recovery Strategy for the Grey Whale (Eschrichtius robustus), Atlantic Population, in Canada ). Dsp-psd.pwgsc.gc.ca (2012-07-31). Retrieved on 2012-12-20.〕 The common name of the whale comes from the gray patches and white mottling on its dark skin.〔(Gray Whale ''Eschrichtius robustus'' ). American Cetacean Society〕 Gray whales were once called devil fish because of their fighting behavior when hunted.〔(Gray Whale ). Worldwildlife.org. Retrieved on 2012-12-20.〕 The gray whale is the sole living species in the genus ''Eschrichtius'', which in turn is the sole living genus in the family Eschrichtiidae. This mammal descended from filter-feeding whales that developed at the beginning of the Oligocene, over 30 million years ago. The gray whale is distributed in an eastern North Pacific (North American) population and a critically endangered western North Pacific (Asian) population. North Atlantic populations were extirpated (perhaps by whaling) on the European coast before 500 AD and on the American coast around the late 17th to early 18th centuries. However, on May 8, 2010, a sighting of a gray whale was confirmed off the coast of Israel in the Mediterranean Sea, leading some scientists to think they might be repopulating old breeding grounds that have not been used for centuries.〔 In May and June 2013 a gray whale was sighted off the coast of Namibia – the first confirmed in the Southern Hemisphere. The round-trip journey of one gray whale has set a new record for the longest mammal migration, covering a distance of more than 22,000 kilometres across the Pacific Ocean. Her migration has shown new insight into how endangered species are making drastic changes in their life style. ==Taxonomy== The gray whale is traditionally placed as the only living species in its genus and family.〔(The Paleobiology Database Eschrichtiidae entry ) accessed on 26 December 2010〕 Recent DNA analysis indicates certain rorquals of the family Balaenopteridae, such as the humpback whale, ''Megaptera novaeangliae'', and fin whale, ''Balaenoptera physalus'', are more closely related to the gray whale than they are to some other rorquals, such as the minke whales. John Edward Gray placed it in its own genus in 1865, naming it in honour of zoologist Daniel Eschricht. The common name of the whale comes from its coloration. The subfossil remains of now extinct gray whales from the Atlantic coasts of England and Sweden were used by Gray to make the first scientific description of a species then surviving only in Pacific waters. The living Pacific species was described by Cope as ''Rhachianectes glaucus'' in 1869. Skeletal comparisons showed the Pacific species to be identical to the Atlantic remains in the 1930s, and Gray's naming has been generally accepted since. Although identity between the Atlantic and Pacific populations cannot be proven by anatomical data, its skeleton is distinctive and easy to distinguish from that of all other living whales. Many other names have been ascribed to the gray whale, including desert whale, devil fish, gray back, mussel digger and rip sack. The name ''Eschrichtius gibbosus'' is sometimes seen; this is dependent on the acceptance of a 1777 description by Erxleben. 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「Gray whale」の詳細全文を読む スポンサード リンク
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