Maybe the old preachers were on to something about the missionary position being a sign of civilisation. Leah (centre), the female western gorilla first spotted using a stick as a measuring rod to test the depth of a lake in 2005, was recently seen mating face to face with George, the dominant male in their group in the Nouabale-Ndoki National Park in the Republic of Congo. Thomas Breuer, of the Max Planck Institute for Evolutionary Anthropology in Germany, was the scientific voyeur, according to Nature.com, the science weekly's Web news service.

Until now, wild gorillas have been known to have sex only face to back, though those in captivity and bonobos (or pygmy chimpanzee) in the wild had been spotted doing it in the manner pictured.

Does her tool-making ability make her a sophisticate among her brutish mates in carnal matters? Dr Breuer wouldn't speculate, saying more research was needed. But one thing we know for sure - her behaviour has helped spread her considerable fame far and wide.