Be heard on the issues that matter most to you!
SCIENCE
In Ducks, War of the Sexes Plays Out in the Evolution of Genitalia
By CARL ZIMMER
Published: May 1, 2007
Male ducks may have such extreme genitals because the females do too.
thanks zelda, i just got around to reading this article. i like to know that scientists think the same as the rest of us....
Dr. Brennan was oblivious to bird phalluses until 1999. While working in a Costa Rican forest, she observed a pair of birds called tinamous mating. “They became unattached, and I saw this huge thing hanging off of him,” she said. “I could not believe it. It became one of those questions I wrote down: why do these males have this huge phallus?”
“So what does the female look like?” she said. “Obviously you can’t have something like that without some place to put it in. You need a garage to park the car.”
it answered a few questions for me as i have wondered how birds "do it". i don't recall ever seeing a male bird mounting a female, but maybe they just prefer privacy and darkness...maybe she thinks her bottom is too big??
anyway, i did find the theory about the female beng able to expell unwanted sperm something that could be helpful to humans. apparently there a lot of duckie rapists out there!!!
Dr. Brennan argues that elaborate female duck anatomy evolves as a countermeasure against aggressive males. “Once they choose a male, they’re making the best possible choice, and that’s the male they want siring their offspring,” she said. “They don’t want the guy flying in from who knows where. It makes sense that they would develop a defense.”
Female ducks seem to be equipped to block the sperm of unwanted males. Their lower oviduct is spiraled like the male phallus, for example, but it turns in the opposite direction. Dr. Brennan suspects that the female ducks can force sperm into one of the pockets and then expel it. “It only makes sense as a barrier,” she said.
To support her argument, Dr. Brennan notes studies on some species that have found that forced matings make up about a third of all matings. Yet only 3 percent of the offspring are the result of forced matings. “To me, it means these females are successful with this strategy,” she said.
Dr. Brennan suspects that when the females of a species evolved better defenses, they drove the evolution of male phalluses. “The males have to step up to produce a longer or more flexible phallus,” she said.
