It's a well-established fact that ducks are having way kinkier sex than you, but new research shows they're also having safer sex while they're doing it. Duck semen kills germs--protecting sperm from damaging bacteria--and lady ducks might be able to tell which guy ducks have the most antibacterial semen just by looking at how colorful their beaks are, the BBC's Ella Davies reports.

Scientists already knew that female ducks considered beak beauty when picking mates. But now they realize that a handsome beak indicates stronger sperm and a lower risk of sexually transmitted diseases. Mallards with bright yellow pigments had the semen that was the most lethal to bacteria, researchers at the University of Oslo found.

This is not even close to being the first article about ducks' dating life, which, by the way, makes the human singles scene look absolutely delightful. Ducks must try to find their one true love (for the mating season) in the midst of an evolutionary genital arms race. A lot of duck sex is rape, Radiolab's Jad Abumrad and Robert Krulwich explained a few years ago. So lady ducks have evolved labyrinthine vaginas to protect their eggs from hostilely-fired sperm. Their vaginal canals are long, have offramps that lead to dead ends, and twist the opposite direction of duck penises. Male ducks' corkscrewing penises, on the other hand, are ballistic, Discover reminds us: they evert straight into their partner's vagina.

Here is a video of that corkscrewing phallus, because you just really do have to watch it. For science!
 

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Elspeth Reeve