Does same-sex attraction happen in animals too?
Is homosexual behaviour seen in other species? What do they do? Why? Find out in this week's Question of the Week...
In this episode
00:00 - Are other animals gay?
Are other animals gay?
Paul Vasey, Professor of Psychology and Director of Laboratory of Comparative Sexuality at the University of Lethbridge...
Khalil - There are lots of behaviours that we sometimes think of as exclusively human but in many cases upon investigation, we find out we're not so different from our animal cousins. To see if this is the case here, I heard from Dr. Paul Vasey from the University of Lethbridge in Canada.
Paul - Same-sex sexual behaviour such as courtship, mounting and pair bonding has been documented in well over 100 species worldwide. Same-sex sexual preferences in animals are harder to document conclusively because this requires demonstrating that an individual chooses a same-sex sexual partner, even though opposite-sex mates are both available and willing. Despite the fact that such data can be difficult to collect, preferences for sexual partners of the same sex have been documented in a number of animal species, most notably Japanese monkeys. In that particular primate species, females in certain populations routinely choose female sexual partners despite the fact that motivated male mates are available. In most species, individuals that engage in same-sex sexual behaviour also engage in sex with the opposite-sex mates, so overall they exhibit a bisexual pattern of sexual orientation. In domestic sheep however, about 6-10% of males only court other males and engage in same-sex sexual behaviour exclusively, never interacting sexually with females. Consequently, scientists talk about these rams as being homosexual with respect to their sexual orientation.
Khalil - This is higher than many estimates of homosexuality in the human population. Here in the UK for example, the Office for National Statistics reported in 2011 that roughly 1.5% of adults describe themselves as gay or lesbian. Estimates vary however and mostly rely on self-reported survey data which can result in inaccuracies. But why do animals exhibit homosexual behaviours in the first place? it certainly won't accomplish the most obvious purpose of mating which is to produce offspring.
Paul - In many instances, animals use same-sex sexual behaviour to facilitate adaptive social goals. For example, bonobos or pygmy chimpanzees, use same-sex genital rubbing to reduce tension associated with food sharing, to form alliances, and to reconcile conflicts. However, in some species like Japanese monkeys, individuals engage in same-sex sexual interaction simply because they're sexually gratified and not because they serve any sort of social function.
Khalil - Whether it's to enhance their social position, improve group cohesion or simply because they enjoy it, there are many natural examples of nonhuman animals exhibiting homosexual and bisexual behaviour. There is, however, no evidence of animals being ostracised for this, so homophobia appears to be a uniquely human trait. Food for thought, right?
Next week, we'll be getting hands on with this question from Hannah...
Hannah - I've heard that London cab drivers get bigger parts of their brain from having to know where all the roads are and I'm wondering if the bit of my brain that makes my right thumb type text messages on my phone might also be changing.