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| unranked_subordo = Cetacea | unranked_superfamilia = Odontoceti | familia = Delphinidae | genus = ''Tursiops'' | genus_authority = Gervais, 1855 | subdivision_ranks = Species | subdivision = See text | range_map = Cypron-Range Tursiops truncatus.svg | range_map_caption = Common bottlenose dolphin range (in blue) }} Bottlenose dolphins, the genus ''Tursiops'', are the most common and well-known members of the family Delphinidae, the family of oceanic dolphin.〔 Recent molecular studies show the genus contains two species, the common bottlenose dolphin (''Tursiops truncatus'') and the Indo-Pacific bottlenose dolphin (''Tursiops aduncus''), instead of one. Research in 2011 revealed a third species, the Burrunan dolphin (''Tursiops australis''). Bottlenose dolphins inhabit warm and temperate seas worldwide. Bottlenose dolphins live in groups typically of 10–30 members, called pods, but group size varies from single individuals up to more than 1,000. Their diets consist mainly of forage fish. Dolphins often work as a team to harvest fish schools, but they also hunt individually. Dolphins search for prey primarily using echolocation, which is similar to sonar. They emit clicking sounds and listen for the return echos to determine the location and shape of nearby items, including potential prey. Bottlenose dolphins also use sound for communication, including squeaks and whistles emitted from the blowhole and sounds emitted through body language, such as leaping from the water and slapping their tails on the water surface. Numerous investigations of bottlenose dolphin intelligence have been conducted, examining mimicry, use of artificial language, object categorization, and self-recognition. They can use tools (sponging) and transmit cultural knowledge across generations, and their considerable intelligence has driven interaction with humans. Bottlenose dolphins are popular from aquarium shows and television programs such as ''Flipper''. They have also been trained by militaries to locate sea mines or detect and mark enemy divers. In some areas, they cooperate with local fishermen by driving fish into their nets and eating the fish that escape. Some encounters with humans are harmful to the dolphins: people hunt them for food, and dolphins are killed inadvertently as a bycatch of tuna fishing and by getting caught in crab traps. Bottlenose dolphins have the second largest brain to body mass ratio of any mammal on Earth (humans have the largest), sharing close ratios with those of humans and other great apes, which more than likely attributes to their incredibly high intelligence and emotional intelligence.〔(25 Most Intelligent Animals On Earth ). list25.com (3 June 2013)〕 ==Taxonomy== Scientists were long aware that ''Tursiops'' dolphins might consist of more than one species. Molecular genetics allowed much greater insight into this previously intractable problem. The consensus is two species exist,〔 〕 although a third distinct species was described in 2011: * The common bottlenose dolphin (''T. truncatus'') is found in most tropical to temperate oceans; its color is grey, with the shade of grey varying among populations; it can be bluish-grey, brownish-grey, or even nearly black, and is often darker on the back from the rostrum to behind the dorsal fin. *: The Black Sea bottlenose dolphin (''T. t. ponticus'') lives in the Black Sea.〔 〕 * The Indo-Pacific bottlenose dolphin (''T. aduncus'') lives in the waters around India, northern Australia, South China, the Red Sea, and the eastern coast of Africa; the back is dark-grey and the belly is lighter grey or nearly white with grey spots.〔 〕 * The Burrunan dolphin (''T. australis''), found in the Port Phillip and Gippsland Lakes areas of Victoria, Australia, was described in September 2011 after research showed it was distinct from ''T. truncatus'' and ''T. aduncus''. The following is sometimes recognized as a subspecies of ''T. truncatus'': * The Pacific bottlenose dolphin (''T. gillii'' or ''T. t. gillii'') lives in the Pacific, and has a black line from the eye to the forehead.〔 (【引用サイトリンク】url=http://www.ubio.org/apps/Hershkovitz/index.php?func=s&ID=42&t=s )〕 The two ecotypes of the common bottlenose dolphin within the western North Atlantic〔 (【引用サイトリンク】url=http://www.nmfs.noaa.gov/pr/pdfs/sars/ao2003dobn-wnos.pdf )〕 are represented by the shallower water or coastal ecotype and the more offshore ecotype.〔 Their ranges overlap, but they have been shown to be genetically distinct.〔 They are not currently described, however, as separate species or subspecies. In general, genetic variation between populations is significant, even among nearby populations.〔 As a result of this genetic variation, other distinct species currently considered to be populations of common bottlenose dolphin are possible.〔 Old scientific data do not distinguish between the two species, making it useless for determining structural differences between them. The IUCN lists both species as data deficient on their Red List of endangered species because of this issue.〔 (【引用サイトリンク】 title=Tursiops truncatus: Species Information )〕 Some recent genetic evidence suggests the Indo-Pacific bottlenose belongs in the genus ''Stenella'', since it is more like the Atlantic spotted dolphin (''Stenella frontalis'') than the common bottlenose.〔 〕〔 〕 Dolphins belong to the Odontoceti (Toothed Whales) suborder, the largest of them is the sperm whale. The sister branch of Odontoceti is Mysticeti (Baleen Whales), the largest of them is the blue whale. 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「Bottlenose dolphin」の詳細全文を読む スポンサード リンク
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