Does homosexual behaviour exist among gorillas?

Such behaviour has been observed under certain conditions, both between females and between males. Among free-ranging gorillas, homosexual behaviour has been observed in mountain gorillas.

Female gorillas: Adult gorilla females are sexually active almost exclusively during oestrus, i.e. during the phase of their cycle when they are ready to conceive. During this time, they demonstrate their interest in mating mainly to males, but occasionally they seem to be sexually attracted to female group members. The two females then sit together in close physical contact, such as a close embrace, and rub their genitals on the ground or on the other female’s body.

Male gorillas: Homosexual behaviour is observed very rarely in harem groups (occasionally during play between youngsters), but it is common in all-male groups. Silverbacks approach their (younger) partners with the vocalisations they usually produce when mating with females. If the younger partners take the initiative, they are more likely to take on the role of the female. The copulation itself and the positions taken by the partners resemble those of heterosexual couples.