Same-sex sexual behaviour in primates is incredibly common - but why? Despite seemingly having no evolutionary advantage, scientists have now noticed something counterintuitive. This behaviour happens much more often in high-stress environments, where food is scarce, suggesting it may aid with social cohesion. It may even improve the success of straight sex - increasing the number of offspring in a group. Hear the full story on The world, the universe and us, a news podcast for the insatiably cu