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The southern elephant seal (''Mirounga leonina'') is one of the two extant species of elephant seals. It is both the largest pinniped and member of the order Carnivora living today, as well as the largest Antarctic seal. The seal gets its name from its great size and the large proboscis of the adult males, which is used to make extraordinarily loud roaring noises, especially during the mating season. Rather larger at average than the male northern elephant seal (''Mirounga angustirostris'') (which is 40% lighter) and male walrus (''Odobenus rosmarus'') (the average North Pacific bull, of the larger race, is 2.5 times lighter), the adult bull southern elephant seal is without rival the largest carnivoran alive.〔(''Mirounga angustirostris''. Northern Elephant Seal ). Smithonian National Museum of Natural History〕〔Carling, M. (1999). (Odobenus rosmarus walrus ). Animal Diversity Web〕〔(Walrus. Odobenus rosmarus ) . National Geographic〕 An average adult male southern elephant seal weighs six to seven times more than the largest terrestrial carnivorans, the polar bear (''Ursus maritimus'') and Kodiak bear (''Ursus arctos middendorffi'').〔 N.B. However, see: (Wiktionary > carnivore )〕〔Wood, The Guinness Book of Animal Facts and Feats. Sterling Pub Co Inc (1983), ISBN 978-0-85112-235-9〕 ==Description== The southern elephant seal is distinguished from the northern elephant seal (which does not overlap in range with this species) by its greater body mass and a shorter proboscis. The southern males also appear taller when fighting, due to their tendency to bend their backs more strongly than the northern species. This seal shows extreme sexual dimorphism in size, seemingly the largest of any mammal by mass, with the males typically five to six times heavier than the females. In comparison, in two other very large marine mammals with high size sexual dimorphism, the northern elephant seal and the sperm whale (''Physeter macrocephalus''), the males weigh on average about three times as much as the females, and only more than four times as heavy in exceptionally heavy bull specimens. While the females southern elephant seal typically weighs and measures long, the bulls typically weigh and measure from long.〔(【引用サイトリンク】 Southern Elephant Seal )〕 An adult female averages in mass, while a mature bull averages about . Studies have indicated elephant seals from South Georgia are around 30% heavier and 10% longer on average than those from Macquarie Island.〔 The record-sized bull, shot in Possession Bay, South Georgia, on 28 February 1913, measured long and was estimated to weigh a hulking , although it was only partially weighed piecemeal.〔 The maximum size of a female is and . The eyes are large, round, and black. The width of the eyes, and a high concentration of low-light pigments, suggest sight plays an important role in the capture of prey. Like all seals, elephant seals have hind limbs whose ends form the tail and tail fin. Each of the "feet" can deploy five long, webbed fingers. This agile dual palm is used to propel water. The pectoral fins are used little while swimming. While their hind limbs are unfit for locomotion on land, elephant seals use their fins as support to propel their bodies. They are able to propel themselves quickly (as fast as ) in this way for short-distance travel, to return to water, to catch up with a female, or to chase an intruder. Pups are born with fur and are completely black. Their coats are unsuited to water, but protect infants by insulating them from the cold air. The first moulting accompanies weaning. After moulting, the coats may turn grey and brown, depending on the thickness and moisture of hair. Among older males, the skin takes the form of a thick leather which is often scarred. Like other seals, the vascular system of elephant seals is adapted to the cold; a mixture of small veins surround arteries, capturing heat from them. This structure is present in extremities such as the hind legs. 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「Southern elephant seal」の詳細全文を読む スポンサード リンク
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