While it has long been known that bonobos engage in homosexual acts, much less is known about the behaviours of other Great Apes.
Now, for the first time, homosexual behaviour between female gorillas has been documented by an Australian scientist.
While conducting a study on the feeding ecology of Rwanda’s mountain gorillas, Associate Professor Cyril Grueter from the University of Western Australia saw homosexual behaviour between females and decided to investigate further.
[The first recorded homosexual activity among female gorillas [Image: Associate Professor Cyril Grueter, UWA]
After studying 22 gorillas, Professor Grueter found 18 engaged in homosexual activity of some kind.
Several theories were tested, including asserting dominance, making up after a fight and strengthening social bonds, but none seemed to fit.
“So a more prosaic explanation was considered - that homosexual behaviour reflects elevated arousal, as there was evidence that homosexual behaviour was more frequent at times when females also engaged in heterosexual copulations,” said Professor Grueter.
“My impression is that these females derive pleasure from sexual interaction with other females.”
This theory is in line with Professor Grueter’s observations of females directing their sexual advances to other females after the male showed no interest, so females served as an alternative outlet for their libido.
The research has been published in PLOS ONE Journal.