Same-sex sexual behaviour in nonhuman primates

Same-sex sexual behaviour occurs across the animal kingdom, and is observable in various invertebrate and vertebrate clades. Nonhuman primates are known to exhibit same-sex sexual behaviour more frequently than other mammalian groups. The drivers and origins of this behaviour are poorly understood, and multiple contrasting hypotheses have been posited. Writing in Nature Ecology & Evolution, Coxshall and colleagues identify key social and ecological drivers of same-sex sexual behaviour in nonhuman primates.

The drivers of this behaviour are therefore complex; it is determined by a suite of characteristics that operate collectively. Considering their results, the authors suggest that same-sex sexual behaviour is context dependent, and perhaps driven by stress from environmental or social factors that results in strong relationships between individuals. This study highlights the importance of a broad phylogenetic scope alongside granular trait data for biotic and abiotic factors when exploring the evolution of animal sexual behaviour.