Very Important Scientists of the Month: Thomas Breuer & Mireille Hockemba

Doin' it gorilla-style
from New Scientist.com
Michael Marshall, online editorial assistant

Well, we had to have a Valentine's Day post, so here it is. For the first time, scientists have photographed wild gorillas mating face-to-face (see Photo).

Thomas Breuer & Mireille Ndoundou Hockemba, of the Wildlife Conservation Society, observed the behaviour during a long-term study of western gorillas in the Republic of Congo. They reported their findings in the April 2007 issue of Gorilla Gazette, but the photos have only now been released.

Face-to-face mating is unusual among primates. It's technically called ventro-ventral copulation, and is only frequently observed in bonobos and, of course, humans. Most primates prefer the dorso-ventral position, which our more plainly spoken readers may know as doggie-style.

The gorilla shown in the picture, who researchers call Leah, is something of a celebrity. In 2005 she was the first wild gorilla observed using a tool - she dipped a long stick into a pool of water to test its depth before wading in.

The story got me wondering about the evolutionary reasons for these different mating behaviours. On the face of it, you could argue that one sexual position is pretty much as good as another (unless you're endangering yourself by performing weird contortions, which seems to be a purely human preoccupation). After all, the point is to deliver the sperm to the egg in as efficient a way as possible, and so long as the male is fully inserted, what difference can it make?

However, some species copulate for reasons other than breeding. Famously, bonobos engage in large quantities of sex, partly as a way of forming and maintaining social bonds. They have also been observed having sex face-to-face, not to mention a whole catalogue of other activities including (and before we get complaints, this is the official term) penis fencing.

That suggests to me that face-to-face mating could have evolved to help strengthen emotional and social bonds, and promote teamwork. Focusing on your partners face would presumably emboss it in your memory, helping you to form a relationship with them. It has also been shown that eye contact makes you more attractive. Why this is so is unclear, but might it be a marker of openness and interest?

Oh, and in case anyone is wondering, the third gorilla (on the right of the picture) is Leah's young daughter Nancy. So probably not a gorilla peeping Tom - though given the range of sexual behaviours observed in primates, I won't be surprised if some of them engage in voyeurism as well.

more reports on Thomas & Mireille's work can be found at the links below:

*nature.news: Gorillas in the missionary position
*sciencedaily.com: Unique Mating Photos Of Wild Gorillas Face To Face
*reuters.com: Gorillas caught in face-to-face love action
*nationalgeographic.com: Gorillas Photographed Mating Face-to-Face -- A First
*NY Times blog: The Ultimate Valentine Card: Full-Frontal Gorilla Love