Homosexual behaviour is hardly unheard of in the animal kingdom. But for the first time, a biologist has documented evidence of female gorillas in the jungle getting hot and steamy together.
The behavior was observed in Volcanoes National Park, Rwanda by a researcher from the University of Western Australia (UWA). The findings were recently published in the online journal PLOS ONE.
The study, led by Dr. Cyril Grueter, associate professor of UWA’s School of Anatomy, Physiology and Human Biology, details how he observed females engaging in “genital closeness” and “genital rubbing,” with pelvic thrusts. It also notes that the gorillas were “uttering copulatory vocalizations” during the act – which presumably is scientific language for “talking dirty”. He also managed to capture photographs of the act, which so far has only ever been observed in captivity.
But this was far from a one-off occurrence. It was discovered that 18 out of the 22 studied female gorillas were also found to engage in sexual activity with other females.
“Given that all these observations come from wild groups, not gorillas held in captivity, it is obvious that homosexual activity is part of the gorillas’ natural behaviour,” Dr. Grueter said in a statement. “My impression is that these females derive pleasure from sexual interaction with other females.”
This stands in contrast to other theories that homosexual behaviour in primates is used either as an aggressive assertion of dominance or as a form of social bonding.
Dr. Grueter also noted what he called a “pornographic effect”. In a few instances, he noticed that females would engage in same-sex behavior just shortly after they had witnessed an adult male initiate sex with another female. This suggests that this behavior could act as an alternative outlet for their sexual arousal.
Alternatively, another hypothesis of the study, which Greuter readily admits has remained unverified, is that females engage in this behaviour to decrease other female's motivation to have sex with males, in order to secure their own reproductive success.