In recent years, studies on homosexuality in the animal world have multiplied, with particular attention to non-human primates. This research has led us to discover that homosexual behaviors are neither a human invention nor a rarity in the animal world.
Among primates alone there are 59 different species in which they have been observed, and now, thanks to a study from Imperial College London, we have a more precise idea of why these behaviors develop, and what the probable role of homosexuality in monkeys is. The study was published on Nature Ecology & Evolution.
An omnipresent behavior. The first step of the study was to identify the species of non-human primates in which homosexuality is present: the analysis returned, as mentioned, 59 different species, including chimpanzees, mountain gorillas and macaques. This result alone suggests two possible explanations for the birth of homosexuality: either it has very ancient origins, at the roots of the evolutionary family tree of primates, or it has evolved several times and independently in different species.
Environmental factors. There are still no elements to establish which of the two is the correct answer, but the interest of the authors of the study is actually concentrated elsewhere: what are the elements that “trigger” the evolution of homosexuality?
The comparison between species first demonstrated a fundamental fact: homosexual behaviors are more widespread in those species that live in drier environments, with scarce resources and a greater risk of predation.
Make love, don’t make war. This, according to the authors, means that homosexuality also emerges (perhaps above all) due to environmental causes: this type of relationship improves cohesion and mitigates competition, and this in turn increases the chances of survival of the group even in more hostile environments. However, there are not only environmental factors behind homosexuality, which is more widespread in species that live longer, and especially in those with a more complex social life and in which there are notable differences in size between males and females – a classic indicator of fierce competition.
Social purpose. In short: not only is homosexuality widespread among primates, but it also has an environmental origin, a social purpose and a strong adaptive value. However, the authors warn against a possible logical fallacy, which is that of associating these results also with humans.
The fact that we too are primates does not mean that homosexuality has the same function for our species: the authors point out that “sexual orientation, preferences and identity in humans are complex factors”and we cannot apply to our species the same conclusions that apply to other primates.
