Same-sex sexual behaviour in non-human primates may help reinforce social bonds and maintain group stability during environmental or social stress, according to new research. Scientists analysed reports across 59 primate species, including chimpanzees, Barbary macaques and mountain gorillas, and found the behaviour to be widespread. The study, led by researchers including Prof Vincent Savolainen of Imperial College London and published in Nature Ecology & Evolution, suggests the behaviour is more common in species facing scarce resources, higher predation risk and harsher climates.
The researchers found same-sex behaviour was also linked to longer lifespans, pronounced size differences between sexes and complex social hierarchies, all markers of intense social competition. First author Chloe Coxshall said both genetic and environmental factors appear to influence the behaviour, which may reduce tension, increase cooperation and help groups navigate challenges. While the authors cautioned against directly applying the findings to humans, they noted early human species may have faced similar pressures. Independent experts welcomed the study’s contribution to understanding primate sociality, while stressing that human sexuality remains far more complex and should not be simplistically compared to animal behaviour.
