Same-sex sexual behaviour among non-human primates may help reinforce social bonds and reduce tension when groups face environmental or social pressures, researchers suggest. Writing in Nature Ecology & Evolution, scientists led by Prof Vincent Savolainen of Imperial College London analysed records from 59 primate species, including chimpanzees, Barbary macaques and mountain gorillas. They found the behaviour to be widespread and more common in species living in harsh, dry environments with scarce resources and higher predation risks.
The study indicates such behaviour is also linked to longer lifespans, pronounced size differences between sexes and complex social hierarchies, all traits associated with intense social competition. Lead author Chloe Coxshall said environmental influences on this behaviour have often been overlooked. The researchers argue same-sex behaviour can increase bonding, lower aggression and help groups navigate challenges. While they caution against direct comparisons with humans, they note early human species likely faced similar pressures. Independent experts welcomed the findings but stressed that human sexuality remains far more complex and should not be directly inferred from animal behaviour.
