Researchers Learn How Female Bonobos Hold Their Own Against Their Larger, More Aggressive Male Counterparts

The females enact a very simple solution by utilizing power in numbers.

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As much as we strive for “normalcy” or to “fit in” with the status quo, outliers excite us. We’re fascinated when a person or group takes an alternative path and want to understand what leads them to do so. We analyze every aspect of these mavericks, whether they bring good or bad to society, to understand why they are the way they are.

Well, in the world of primates, bonobos are the rebels. Typically, within the great ape evolutionary family tree, males lead and hold the most power, even when outnumbered. However, in bonobo communities, it’s the females who run things, even though they are smaller than their male counterparts. This dynamic has intrigued researchers, especially since bonobos are tied with chimpanzees as our closest living relatives.

To learn more, an international team of scientists has spent nearly three decades investigating what makes the social dynamics of bonobos so distinct. They have discovered a simple yet highly effective strategy that the most successful female bonobos commonly employ.

Our Closest Living Relatives

Chimpanzees often get the credit for being our closest living genetic relative. However, we share just as much DNA (98.7 percent) with bonobos, making the two great apes tied as our closest living cousins.

The two primates share many similarities, especially in terms of appearance, to the extent that bonobos weren’t recognized as a separate species from chimpanzees until 1929. However, upon careful observation, bonobos are typically smaller, leaner, and darker than chimpanzees.

Along with similar appearances, both species exhibit complex social structures and relationships, characterized by hierarchies and impressive communication systems that resemble our own in some ways. Furthermore, chimpanzees and bonobos both utilize sex as a means of resolving social conflicts.

However, chimpanzee and bonobo societies differ in some important ways.

Social Structures

For both species, the males typically remain with the group they’re born into, while the females leave around adolescence to join other communities.

Chimpanzees form social groups and hierarchies in which males outrank females, which makes a certain amount of sense if the males are more likely to stay and are related. Meanwhile, the females come from elsewhere to join the communities. Plus, male chimps are also known for being particularly aggressive, which contributes to their dominance.

Like chimpanzees, most males within any particular group are typically related, while none of the females are. However, the response to this tradition vastly differs between the two species.

While female bonobos leave their natal group during adolescence to join other communities, and males remain in their natal group for life, it’s the females who lead bonobo societies.

Generally speaking, female-dominant social structures are rare among mammals, especially among apes. However, female bonobos join elephants and some whale species as one of the few animals that lead their social groups, typically with the eldest female serving as the matriarch.

Hirearchies

For chimpanzees, social status is typically won and lost through males competing with each other to ascend social ranks by tearing others down. Often, with the help of their male siblings or friends.

Meanwhile, despite spending their whole lives within their natal community and being related to the other males in their group, male bonobo hierarchy is correlated with their mother’s dominance level. The highest-ranking males are the matriarch's sons, while the lowest-ranking males are orphans.

Sex and Parenting

Both species use sex to help ease social tension, relieve stress, strengthen bonds, and repair relationships. However, bonobos are primarily known for their especially heightened sexuality.

Wild and captive bonobos habitually engage in sexual interactions with almost all age and sex combinations (except mothers with sons). Some even say bonobos use sex as casually as a handshake.

Due to the bonobo’s sexual liberation, there is a great deal of paternal uncertainty. As a result, offspring are mostly raised by their single mothers, with the help of their communities. While male bonobos don’t assume “fatherly” roles, they are attentive toward the group’s infants and, unlike chimpanzees, no male bonobo has ever been observed committing infanticide.

When it comes to parenting, many people might assume bonobo mothers would be “supermoms.” Yet, research found that bonobo mothers rarely intervene when a group member is “mean” to their children, unlike the typically overprotective chimpanzee mom.

Temperment

Maybe partly because of their sexual habits, bonobos are typically considered more peaceful than chimpanzees, though their communities aren’t always violence-free. If two groups of opposing bonobos come together, they can get into some serious brawls.

Also, compared to females, male bonobos are larger, louder, and can become highly aggressive. In fact, while chimpanzees have a reputation for being particularly violent, even murderous cannibals, recent research found that male bonobos fight three times more often than male chimps.

Yet, despite the males being bigger, stronger, and more aggressive than their female counterparts, it’s the female bonobos who lead their societies.

This unique social structure, compared to the rest of the great apes, makes scientists like Martin Surbeck — a behavioral ecologist who studies chimpanzees and bonobos in the rainforest — and his colleagues curious about what tips the social advantages in favor of female bonobos, and they have dedicated nearly three decades to finding out.

The Research

Between 1993 and 2021, Surbeck and an international team of researchers from the United States, England, Germany, and the Netherlands observed six wild bonobo communities in the Democratic Republic of the Congo to discover how and why female bonobos lead their communities and successfully assert dominance over their seemingly more threatening male counterparts.

They published the resulting study on April 24, 2025, in the journal Communications Biology.

The Study

While observing the bonobo communities, Surbeck and his colleagues measured the “rank” of each group by tallying the number of times females won conflicts with males, and evaluated the percentage of males that females outranked.

When comparing the information, they found varying levels of cooperation and dominance between the six groups. Surbeck explained to Jason Bittel of National Geographic:

“There is substantial variation in this trait of female power within groups.”

Overall, Surbeck found that around 70 percent of female bonobos outrank males in their communities. However, the percentage varied across specific populations, which suggests that high female bonobo social status is earned, rather than a birthright, and can be challenged.

Supporting this is the fact that such variation also occurs across time.

In their study, the researchers report that in 1998, the females of the Eyengo bonobo group consistently outranked the males and never once backed down from a fight with one. Such high female dominance doesn’t always last, though. Sometimes, as with the Ekalakala bonobo group in 2016, males held the upper hand, with only 18.2 percent of females occupying dominant positions.

However, as with how life seems to work, the pendulum returned to the females’ favor in 2020 when the female bonobos in the Kokolopori community won 98.4 percent of the conflicts against males.

Whilst observing these and more ebbs and flows of bonobo power dynamics over decades, the researchers witnessed the apes employ various strategies during conflicts, along with the outcomes. In a statement by the Max Planck Institute of Animal Behavior, Surbeck said:

“You can win a conflict by being stronger, by having friends to back you up, or by having something that someone wants and cannot take by force.”

However, the most successful female bonobos employed a single approach that proved highly effective.

Winning Strategy

After conducting intensive and time-consuming research, the scientists reached a simple conclusion, which Surbeck summarizes to Bittel:

“We have found what everybody already knows — that when you work together, you’re more successful and you gain power.”

More precisely, the researchers believe forming coalitions helps female bonobos achieve higher social ranks most often. These female-led coalitions typically comprise three to five bonobos, which sometimes include males.

It’s somewhat surprising that male bonobos would join a female-led coalition, considering that when these groups exhibited aggression, it was predominantly (85 percent) directed at males. Then again, the coalitions won 61 percent of the fights, so perhaps the males simply wanted to join a winning team.

Regardless, the scientists note in the study that while the males sometimes joined a female coalition against other males, they were always subordinate and never led a charge.

The females, however, had every opportunity to rise in social rank within these coalitions, especially after providing quality backup to other females during a conflict.

As for what initiated the formation of female coalitions, the researchers said it varies as well. In one site, Wamba, the female bonobos amassed social dominance in response to males behaving aggressively toward older females. Meanwhile, in three other bonobo communities, females formed coalitions after males showed aggression toward offspring.

When female bonobo coalitions turn on a male who’s stepping out of line, their reactions vary between screaming while chasing him through the trees to inflicting serious injuries. Surbeck told Bittel,

“In bonobo communities, females have a lot to say. And that's very different from chimpanzee communities where all adult males outrank all females in the group.”

The fact that female bonobos dominate their social groups by banding together to take on the trouble-making males is impressive and fascinating. That the females forming these alliances are not related and did not grow up together — sometimes they aren’t even friends — is even more so.

Zanna Clay, a primatologist and comparative psychologist at Durham University in the United Kingdom, who was not involved with the study, explained to Bittel that,

“The degree of group variation in female coalitions and female power between bonobo communities was one of the most fascinating findings from this study. This challenges the ‘one-size-fits-all’ view of our closest cousins, and suggests that like us, they show fascinating nuance and important variation in their behavior and traits.”

This research also indicates that male dominance is not inevitable. If great apes can be flexible in their social structures, so can we.

Broader Implications

The implications of Surbeck and his team’s extensive research excite other scientists who didn’t hold back from sharing some potential parallels between our ape cousins and ourselves.

Laura Simone Lewis, a biological anthropologist at the University of California, Berkeley, who was not part of the research, told Bittel:

“As bonobos are our closest living relatives along with chimpanzees, these data also provide support for the idea that humans and our ancestors have likely used coalitions to build and maintain power for millions of years.”

Christopher Krupenye, a professor at Johns Hopkins University who studies cognition in primates but was also not involved in the study, seems to agree with Lewis. He stated to Dino Grandoni of the Washington Post:

“In concert with related work in chimpanzees and other primates, it seems very likely that coalitions have been a tool for building and maintaining power for millions of years, dating back at least to our common ancestor with the other apes.”

Lewis took things even further when she shared with Bittel that,

“Women are often victims of male violence around the globe. This study could provide insight into how women could build power to better protect ourselves from male violence by forming and maintaining coalitions, or alliances, with one another, just like our bonobo cousins.”

Surbeck agreed that humans might find some inspiration from the research.

“It tells us that male dominance and patriarchy is not evolutionarily inevitable. This reinforces the idea that apes and humans are very innovative and flexible in their behavior. If anything, I think we can say that it does give us some hope.”

In the Future

As enduring and comprehensive as the new research is, Krupenye told Sara Hashemi of Smithsonian Magazine that more work needs to be done. One thing bugging him is whether the coalitions give female bonobos their power or if they form because the females already have power.

However, considering bonobos are an endangered species, we must first prioritize their protection. Currently, the only place where the approximately 50,000 remaining wild bonobos live is in the Democratic Republic of the Congo. As Surbeck told Annie Roth of the New York Times,

“Bonobos are an endangered species. As our closest living relative, they help us look into our past. If we lose them, we lose a mirror for humanity.”

Ideally, we’d protect bonobos because they’re incredible and intelligent animals, but since we can be a selfish species, we should at least protect them for our sakes — and Surbeck makes a great point.

Perspective Shift

Once upon a time, many other human species lived on Earth. Our Homo sapiens ancestors coexisted with at least a few, a couple of which we even interacted with and interbred. Their genetics live on within us today, even though we’re the only human species left.

Now, alone, we constantly search for other intelligent animals, and we’re finding them — Elephants, dolphins, the octopus, chimpanzees, and bonobos, among others, all exhibit remarkable intelligence.

Perhaps we shouldn’t let another one of our relatives go extinct, especially when, even after between 5.5 and 6.3 million years of evolutionary divergence, we - still - have - so - many - similarities.

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Bonobos at the San Diego Zoo - Image Source: Wikimedia Commons