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Why penguins dumped flight for flippers

发布时间:2017-05-22 06:01:02来源:未知点击:

A CANADIAN seabird may help explain why penguins cannot fly. The thick-billed murre (Uria lomvia) is a diving bird that flies – just not very well. In fact, when Robert Ricklefs at the University of Missouri at St Louis and his colleagues studied murres in flight, they found the bird used almost three times as much energy as the bar-headed goose, previously considered the least efficient flying bird. Underwater, though, the murre can swim with an efficiency only 30 per cent below the level expected of a penguin of similar size (PNAS, DOI: 10.1073/pnas.1304838110). “You can’t have a wing that’s both good for propulsion in water and in air,” says Ricklef. The murre may ultimately reach a point where using wings as flippers would trump using them for flying,