Zoology: With Peacocks, the Eyespots Have It

© 1994 The Washington Post (LEGI-SLATE Article No. 214551)

Peacocks know that looks count for a lot in this world.

Research has shown that peahens choose their mates based on the quality of their plumage - the size and distribution of "eyespots." But until now, scientists did not know whether that choice had any positive effect for the birds and their offspring, especially because the males do not help raise the brood.

In a letter to the journal Nature, Marion Petrie of Oxford University's Department of Zoology described an experiment in which Petrie raised groups of peafowl sired by different males. The offspring of the males with the most eyespots, Petrie found, were generally larger at 84 days of age than the others. Then, the peacocks were released into the relative wilds of nearby Whipsnade Park, where such predators as foxes thinned the population to 41 percent of its original size within two years. The bigger peacocks were likelier to survive than the punier birds. "The results show the offspring of highly ornamented males tend to grow better and that these advantages translate into differences in the chance of their subsequent survival under almost natural conditions," Petrie concluded. "These data provide support for the idea that females may be gaining good 'viability' genes for their offspring when mating with attractive males."



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