Explosive penises and the anatomical prevention of duck rape: You may not have known this (most of the Ars staff didn’t), but most birds copulate without the benefit of a penis. One of the primary exceptions to this are, of all creatures, ducks. As it turns out, male and female ducks have elaborate and rapidly evolving genitalia. There appears to be a behavioral habit driving this evolution: duck rape or, more properly, forced copulation. It seems that males tend to force themselves on females, and females have been evolving convoluted reproductive passages in order to thwart them.
The paper in question here actually capture video of the male erection process, which normally takes place inside the female: “Eversion of the 20 cm muscovy duck penis is explosive, taking an average of 0.36 s, and achieving a maximum velocity of 1.6 m s−1.” But the female reproductive tract contains awkward bends and blind alleys that can apparently stop the process cold, allowing the female a degree of control over the father of her offspring, regardless of how aggressive he may be.
Buy This Item: [Click here to buy this item]