handicap principle

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handicap principle A controversial idea, advanced by A. Zahavi in 1975, which explains the existence of extravagant male traits (e.g. the tail of a peacock) by proposing that sexual selection favours them because they indicate male prowess: the male demonstrates to females his ability to thrive despite the handicap (in this example of a heavy, cumbersome tail). Similarly, elaborate bird-song may demonstrate the success of the male in finding food quickly, allowing more time for song, and in avoiding predators, and elaborate plumage may demonstrate an ability to control skin and feather parasites. Compare runaway hypothesis.