Thanks to the detailed research of Patricia Brennan and the fluent coverage of it by Ed Yong and Carl Zimmer, a lot of people have not only heard of the impressive duck penis, they’ve seen it in all its explosive glory (if you don’t know what I’m talking about, take a moment to click on the links above — trust me, it’s worth it).
Image from Herrera et al., Fig 1.
But while ducks and their fellow water fowl boast these impressive, large penises, the penes of most birds are nothing to squawk about. Ninety-seven percent — over 10,000 species of birds — have either reduced or non-existant penises that are incapable of penetration. “One of the most puzzling events in evolution is the reduction and loss of the phallus in birds,” explains biologist Marty Cohn in a Cell Press Video Abstract. “It’s remarkable that a group of animals would eliminate a structure that is so important for reproduction.” Given that, like us, birds conceive through internal fertilization, you would think a penis would be essential. How else is the male’s sperm supposed to get all up in the female’s vagina?
While scientists still debate about why the chicken lost most of its penis, a new study published this week in Current Biology finally explains how it was lost, a crucial first step in unraveling this evolutionary enigma. Continue reading “Why did the chicken cross the road? Maybe it was looking for its penis.”
Facebook gleefully reported earlier this week 
