Same-sex sexual behaviour among non-human primates may help reinforce social bonds and maintain group cohesion during environmental or social stress, according to new research. The study, published in Nature Ecology & Evolution, analysed reports of such behaviour across 59 primate species, including chimpanzees, Barbary macaques and mountain gorillas. Researchers from Imperial College London found the behaviour was more common in species living in harsh, dry environments with scarce resources and higher predation risks.
The analysis suggests same-sex behaviour is linked to complex social systems, longer lifespans, and greater size differences between males and females, traits often associated with intense competition in large groups. Lead author Chloe Coxshall said both genetic and environmental factors appear to influence the behaviour, which may help reduce tension and aggression. Co-author Prof Vincent Savolainen noted the findings could offer insights into early human evolution, though the team cautioned against drawing direct parallels with modern human sexuality. External experts welcomed the study’s evolutionary perspective while stressing that human behaviour is shaped by many additional social and cultural factors.
