Duck penises get bigger when they are surrounded by other males

Depending on what corners of the Internet you frequent, you may have heard about the horrific corkscrew penises ducks use to solicit often non-consensual sex. If you’ve never stopped to wonder about the reproductive habits of this barnyard classic, maybe take a moment to sit down and kiss your blissfully innocent mental image of the bird goodbye, because, that’s right, horrific corkscrew penises. And a new study offers further revelation about the how ducks use this organ to their advantage.

Certain species of ducks’ penises become longer when the birds are fighting with other males to catch a female’s eye. That’s according to a paper published today in the journal The Auk.

The team of researchers, from Mount Holyoke College and other institutions, wanted to study the penises of ducks with different mating styles to see if there were any apparent consequences. So they called up a nearby waterfowl conservancy and asked to organize the birds’ roommate situations.