Sex has been used in conflict resolution for millions of years

New research suggests that using sex to ease social tension may have roots going back more than six million years, to a common ancestor shared by humans, bonobos, and chimpanzees. 

While it’s no surprise that humans don’t only have sex to reproduce, this study highlights a similar pattern in our closest ape cousins, offering a window into how this behavior might have evolved in our own species.

Comparing bonobos and chimpanzees

Bonobos have long been recognized as “hypersexual” apes that turn to sexual activity to diffuse tension and mend rifts after disagreements. 

Chimpanzees, on the other hand, have tended to be seen as more aggressive, leaving scientists uncertain about whether they also rely on sex to settle social conflicts. 

In a study led by Durham University and published in the journal Royal Society Open Science, researchers compared these two species under similar conditions to see how each used sex during tense moments.

The team observed bonobos and chimpanzees at two African great ape sanctuaries, logging more than 1,400 hours of data over seven months in 2019. They focused on two scenarios: after natural social altercations and just before feeding time, when appetites and power dynamics can lead to conflict. 

The findings showed that while both species use sex to ease friction when competition is high – particularly before mealtimes – bonobos tended to rely on post-conflict “make-up sex” more frequently, whereas chimpanzees often used other forms of reassurance, such as grooming and body kissing.

A peek into our evolutionary past

The fact that bonobos and chimpanzees both use sexual contact to manage tension points to an ancient evolutionary trait, one that we humans appear to share. 

“Whilst bonobos, who are famously hypersexual, were more likely to engage in so-called ‘make-up sex’ after periods of conflict, we found that chimpanzees, who some view as our more aggressive cousin, also use sex to ease tensions in many circumstances,” said lead author Jake Brooker, a postdoctoral researcher in Durham’s Department of Psychology.

Because bonobos and chimpanzees diverged from their common ancestor with humans over six million years ago, these findings hint that harnessing sex for social reasons – beyond mere reproduction – may have been part of that ancestral ape’s behavioral toolkit. 

Bonobos’ reputation for “peace through pleasure” may not be so different in spirit from how chimpanzees and humans also use sexual bonds to relieve stress and reinforce alliances.

Using sex to prevent conflict 

Another fascinating observation emerged when the researchers noticed that older apes in both species were more likely to initiate sexual interactions before feeding. This could mean that employing sex to prevent or reduce conflict is a learned or socially reinforced behavior. 

Meanwhile, female bonobos and male chimpanzees showed a particular inclination toward initiating these interactions, though sex occurred across both heterosexual and same-sex pairings.

In contexts following disagreements, bonobos were more prone to using sex to patch things up, while chimpanzees often turned to other comforting gestures. 

This difference might reflect the broader cultural or societal norms within each species – bonobos relying on a more sexually driven approach, and chimpanzees mixing sexual contact with an array of conciliatory activities.

Sex as a social tool

While humans are obviously different from apes in many ways, the study adds to a growing body of evidence that sex can serve social functions, such as conflict resolution, stress relief, and relationship maintenance. 

Since bonobos, chimpanzees, and humans are all closely related, observing similarities in how these behaviors emerge under pressure can teach us more about our shared past.

It also challenges simplistic stereotypes: bonobos aren’t always the carefree “hippies” of the ape world, nor are chimpanzees unrelentingly belligerent. The reality is more nuanced. Even chimpanzees, known for aggressive tendencies, use sexual contact to manage stress when circumstances demand it.

“Against the assumptions of pacifist sex-mad bonobos and aggressive chimpanzees, we found that both species used sex in similar ways during tense situations. This study highlights that beyond reproduction, sex plays an important role in their societies, and most likely for our early ancestors too,” said senior author Zanna Clay, a professor at Durham University.

With further research, scientists hope to learn more about how sex functions in different contexts for these apes, including how it varies in wild populations. 

Such insights could add yet another layer of understanding to the intricate ways humans and our closest relatives navigate social life – both during times of strife and everyday interactions.

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