TL;DR
- A new study reports documented same-sex sexual behavior in 59 nonhuman primate species.
- Researchers found repeated occurrences in 23 species, making it the broadest primate review so far.
- Authors suggest the behavior evolved to ease tension, reduce conflict, and build social bonds in complex groups.
- The review links higher rates to harsh environments, intense competition, predation risk, and strict hierarchies.
- Scientists stress there’s no single “gay gene”—behavior reflects genes + environment.
- The findings don’t claim to explain modern human sexuality, but they undercut the idea that same-sex behavior is “rare” in nature.
Primate hookups aren’t just for babies — and same-sex sexual behavior is part of the deal
Turns out humans aren’t the only primates getting busy in ways that have nothing to do with making babies. A sweeping new study reports same-sex sexual behavior across 59 nonhuman primate species — including bonobos, chimpanzees, and macaques — and argues it likely evolved because it helps primates survive the messiest part of nature: living with each other. The research, published in Nature Ecology & Evolution, is being billed as the most comprehensive review of same-sex behavior in primates to date (humans weren’t included), and it lands with a simple message that will make the “unnatural!” brigade choke on their talking points: this behavior is widespread, and it appears to be useful.
The researchers dug through existing data and observations covering 491 primate species, looking for documented cases of sexual behaviors between members of the same sex — things like mounting and genital contact — while excluding nonsexual interactions to avoid fuzzy interpretations. They found repeated behavior in 23 species, and additional documented instances across dozens more. One of the study’s authors, Imperial College London scientist Vincent Savolainen, said the takeaway is that same-sex behavior isn’t some rare anomaly — it’s woven into primate social life, often as routinely as feeding or fighting.
When the jungle gets stressful, sex becomes “social glue”
Here’s where it gets juicy — and actually, very practical. The authors argue that same-sex sexual behavior likely evolved as a social tool: a way to cool down tension, prevent conflict, build alliances, and keep group life from turning into nonstop chaos. The study suggests it’s more common when primates face tougher conditions: harsher environments, higher predation risk, fiercer competition for resources, or strict dominance hierarchies. Translation: when life is stressful and everybody’s fighting over food, rank, and safety, sexual behavior can function like a pressure valve — or a relationship “currency” some individuals use to navigate the social order.
This idea isn’t brand-new to animal behavior experts, but the scale of the review adds weight. Researchers have long observed, for example, female bonobos engaging in genital rubbing during tense moments, and same-sex behavior is widely documented among macaques and chimpanzees. The study also points to a familiar reality in biology: behavior is typically shaped by both genes and environment, not a single on/off switch.
University of Minnesota evolutionary biologist Marlene Zuk, who wasn’t involved in the work, praised the breadth of the data and used it to spotlight a common misconception: people act like animal sex is always a straight, minimal, reproduction-only transaction. In reality, animal sexual behavior can be social, strategic, and complicated — just like humans love to pretend we invented.
What it means for LGBTQ+ people — and what it doesn’t
The study is careful not to claim it explains modern human sexual orientation, and it doesn’t try to draw a direct line from primate observations to human identity. But let’s be real about the cultural impact: findings like these help dismantle the tired myth that queer behavior is “against nature.” When same-sex behavior shows up across primates — our close evolutionary cousins — it reinforces what LGBTQ+ people have always known: queer existence isn’t a glitch. It’s part of the spectrum of life.
It also supports another crucial point: the science world has moved on from the simplistic idea of a single “gay gene” that dictates everything. As Zuk notes, there isn’t one identifiable gene that guarantees an animal will exhibit only same-sex behavior. Like most traits, it’s influenced by multiple genetic factors interacting with environment and social context. That nuance matters, because anti-LGBTQ rhetoric often leans on fake “biology” that cherry-picks science to police people’s lives.
And there’s an uncomfortable subtext the study calls out: the topic itself has been under-studied — partly because observing and interpreting the behavior can be hard, and partly because funding and researcher bias have historically treated it as taboo or irrelevant. That silence doesn’t erase the behavior; it just leaves the public with ignorance — and ignorance is where stigma thrives.
Bottom line: the primates are doing what primates do — bonding, negotiating, surviving — and same-sex sexual behavior is one of the tools in the kit. For LGBTQ+ communities, that’s another reminder that “natural” isn’t something bigots get to define. Nature already did.