A Perth-based researcher is documenting same-sex sexual behaviour among wild female gorillas for the first time in the mountains of Rwanda. According to Cyril Grueter, an associate professor and primate expert from the University of Western Australia, the behaviour between the two female gorillas is simply motivated by sexual arousal.

Grueter was studying the feeding ecology of mountain gorillas in Rwanda when she encountered the behaviour. After observing 22 female gorillas for 18 months, the researcher found that almost all of the animals practised homosexual behaviours.

“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,” says Grueter. “My impression is that these females derive pleasure from sexual interaction with other females.”

female gorillas

Two male lions cuddling photographed by Belgian lawyer and photographer Nicole Cambre. Photo from Youtube

The female gorillas engaged in sexual activity with each other after the male gorillas showed no interest in them. Apparently, the gorillas used genital stimulation.

After further observations, Grueter concluded that female gorilla sexuality is very flexible, just like how women are more fluid in sexuality than men. The female gorillas can easily switch from heterosexual sex to homosexual sex, engaging in same-sex sexual activity with other female gorillas when no male gorillas are around to mate with them.

Other experts asserted that animals engage in homosexuality activity to assert dominance, bond or settling after a fight. However, there is not enough evidence to support these theories. Nevertheless, the new observations add up to proof that same-sex sexual behaviour is common among animals.

The same-sex behaviour by animals was observed recently by Belgian photographer and lawyer Nicole Cambre. Cambre took photographs of two male lions cuddling with each other.

Others argued that one of the lions is likely a female but Cambre insisted that the animals were males. While many claimed it was a “Brokeback Mountain” moment, University of Minnesota Professor Craig Packer claimed that the behaviour was just another instance of bromance.