As discussed in previous blog posts, a number of unusual sexual behaviors have been documented in human beings, from cutting a hole in one’s pants in order to masturbate easily in public to letting insects bite one’s genitals during sexual activity. However, humans aren’t the only ones with curious sexual proclivities—unusual behaviors also occur in the animal kingdom with some frequency. In this post, I’d like to share what is perhaps the most interesting scientific study of animal sexuality I have ever come across.

On June 5, 1995, Kees Moeliker, the curator of the Natural History Museum of Rotterdam, heard a loud bang just outside of his office [1]. He went over to the window and discovered that a drake mallard had hit one of museum’s windows at full speed and died. Moeliker observed another male mallard came over and start picking at the dead duck’s head. The live mallard then proceeded to mount the corpse and rape it. This activity went on for a full seventy-five minutes, during which time the perpetrator took only two short breaks. Moeliker documented the entire event by taking notes and photos from safely behind the museum's windows. When the necrophiliac mallard was finished, Moeliker secured the violated corpse and stashed it in a freezer for later examination.

I found this observational study fascinating on multiple levels. Of course, the fact that someone would watch a dead duck being raped for over an hour, not to mention take copious notes while doing so, is interesting in and of itself. But what was even more fascinating to me about this article was finding out that neither necrophilia nor homosexuality is all that rare in mallard ducks. In fact, scientists have previously observed male mallards attempting to mate with deceased females, and researchers estimate that up to 1 in 5 mallard duck pairs consist of homosexual males [2]. It turns out that the only unique thing about this case was the combination of mallard necrophilia with homosexuality.

So why did the rape occur in this instance? We don’t know for sure, but Moeliker suspects it was the result of an “attempted rape flight.” What happens in ducks is that when they pair off for mating, some of the males invariably get left out. Those males who fail to find a partner start sexually pursuing every other nearby duck, regardless of whether it is of a different species or of the same sex. Moeliker theorizes that the male mallard who died was simply trying to escape the sexual advances of the other duck until it hit the window.

This probably won’t come as much of a surprise, but Moeliker won a coveted Ig Nobel Prize for Improbable Research for the journal article he wrote describing his observations. In case you aren’t familiar with the Ig Nobels, these distinctions are awarded to scientific research that makes us laugh and think. As you might imagine, sexual scientists are good at winning these awards (see here for another winning study that involves beetles making love to beer bottles). I suppose the prevalence of these awards isn’t necessarily a bad thing for our field, as long as people don’t start calling us “quacks.”

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[1] Moeliker, C.W. (2001). The first case of homosexual necrophilia in the mallard Anas platyrhynchos (Aves: Anatidae). Deinsea, 8, 243-247.

[2] Bagemihl, B. (1999). Biological exuberance, animal homosexuality and natural diversity. London: Profile Books.

Image Source: iStockphoto.com

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