Anatomy differences, other clues suggest coevolution of genital traits
The first intimate duck videos show that it’s mate and checkmate in the battle of the sexes.
High-speed cameras document that a male Muscovy duck can fully extend his 20-centimeter penis in a third of second, says evolutionary biologist Patricia Brennan of Yale University. (Watch the researchers' video.) That may be about all the time he has with a resisting female trying to escape him. Male Muscovy ducks rank among the waterfowl that often fail to take no for an answer.
Also on camera, duck handlers coaxed males to deploy into glass tubes instead of into females. The tubes featured bends and wrong-way spirals that kept the males from extending very far, Brennan and her colleagues report online December 22 in Proceedings of the Royal Society B.
Real female ducks have such shapes, even spirals that squiggle in the direction opposite to male anatomy. And Brennan has proposed that a female duck refusing to