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Sexy Swallows

December 15, 2005

You may think that one of the advantages to settling down is not having to spend so much time on your looks. But a new study in birds suggests that letting yourself go could be a big mistake.


How to keep your mate from straying. I’m Bob Hirshon and this is Science Update.

Even after a guy has settled down, he still has to look sharp—at least if barn swallows are any indication.

[barn swallow sounds]

Evolutionary biologist Rebecca Safran, previously of Cornell University, was part of a team that used ink to intensify the colors of male swallows’ feathers. That makes them sexier to females. Using genetic tests, they found that the chicks born in the nest after the enhancement were more likely to be the male’s biological offspring than before, meaning the females were less likely to cheat on sexier mates. Safran says the intense colors are akin to human status symbols like fancy cars and jewelry.

REBECCA SAFRAN (Cornell University):
Maintaining signals of status and quality are something that we can relate to and something that we spend a lot of time and energy on long after pair bonds have formed—meaning that they probably still have some important function in our society.

I’m Bob Hirshon, for AAAS, the science society.