
Primate same-sex behavior widespread, hinting at social roles in evolution
A Nature Ecology & Evolution study synthesizes data showing same-sex sexual behavior in 59 nonhuman primates (including bonobos, chimpanzees and macaques) with repeated instances in 23 species, suggesting such behavior helps reduce social tension, build bonds, and manage competition under environmental stress—driven by genetics and context rather than reproduction, though not all species are equally studied.













