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Desert Diary
Biology/Expendable Males


Ever wonder why some critters, such as birds, sport all those bright colors? After all, isn't that kind of like telling every predator in the neighborhood, "Here I am"? Exactly! But you'll notice that most often it's the male that's brightly colored, and from the viewpoint of natural selection, often the tradeoff is the chance to reproduce. In many species, it's the female that makes the decision as to who will father her offspring; and on average in these species, it's the most brightly colored male that's chosen.

Now it's not necessarily that the females are so dimwitted that superficialities win them over. At least one suggested explanation is that brightly colored males are healthier than dull ones, and thus more apt to produce high quality young, and beyond being able to produce brilliant colors, the fact that such a male has told every predator within reach to bring it on and has survived, is itself an advertisement of fitness. And if a male doesn't make it? Well, in most species, males are cheap and expendable.
pen and ink

Listen to the Audio (mp3 format) as recorded by KTEP, Public Radio for the Southwest.


Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.

Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.