Why Are Bonobos Called the Peaceful Ape? Facts and Myths

Peaceful compared with whom?

The reputation comes mainly from comparing bonobos with their sister species, the chimpanzee. Chimpanzee males patrol their territory, attack members of neighboring communities and sometimes kill them. Infanticide and violent power struggles also occur within chimpanzee groups.

Bonobos show very little of this. A major study published in 2014 pulled together decades of observations from 18 chimpanzee communities and 4 bonobo communities. It recorded more than 150 killings by chimpanzees but only one suspected killing by bonobos. The authors concluded that lethal aggression is a natural strategy for chimpanzees and not simply a reaction to human disturbance, and that bonobos really are different.

Female alliances keep the peace

The most important reason for bonobos’ calmer society is the power of females. Young females leave their birth group and join another, so the adult females in a community are mostly unrelated. Even so, they form strong friendships and alliances.

When a male harasses a female or tries to take her food, other females often band together to drive him off. Together, females can dominate males, and in most communities a coalition of senior females, with some high-ranking males, leads the group. Male bonobos do not form strong alliances with each other the way chimpanzee males do, so they have less ability to coordinate attacks. A male’s status depends largely on his mother, who supports him throughout her life.

Sex, play and food sharing

Bonobos are famous for using sexual contact, between males and females and within the same sex, as a social tool. It occurs especially when tension rises, such as when a group finds a rich food source, and it is used to greet, reconcile after a quarrel and strengthen bonds. Researchers often describe it as a way of easing stress rather than simply reproduction.

Bonobos also groom, play and share food more freely than chimpanzees. In experiments, bonobos have even chosen to share food with bonobos they had never met before. When neighboring communities meet in the wild, they often mix calmly, groom, play and feed together for hours or days, which would be dangerous for chimpanzees.

Why might bonobos have evolved to be less violent?

Scientists have proposed several ideas, and they may all play a part:

• Food supply. Bonobos live south of the Congo River, where they do not compete with gorillas for the abundant herbs on the forest floor. A steadier supply of food may allow bonobos to travel in larger, more stable groups, so females can stay together and support each other.
• Female choice. Because females are not easily coerced, they can prefer to mate with less aggressive males. Over many generations, this may have favored more tolerant males.
• Self-domestication. Some researchers suggest bonobos underwent a kind of “self-domestication,” in which selection against aggression also produced juvenile-looking features and playful behavior, similar to changes seen in domesticated animals. This idea is debated.
• Concealed ovulation cues. Female bonobos show sexual swellings for much of their cycle, making it harder for males to know exactly when a female is fertile and less useful to fight over her.

Myth: bonobos are gentle hippies

The “hippie ape” image, summed up in the slogan “make love, not war,” is popular but too simple. Bonobos argue, chase, slap and bite. Males compete for rank and access to females, and individuals can be badly injured. Some primatologists have also argued that early descriptions relied heavily on captive bonobos, which may behave differently from wild ones.

A 2024 study comparing wild males at long-term sites found that male bonobos were actually involved in aggressive incidents more often than male chimpanzees, roughly three times as often. The difference was in the kind of aggression: most bonobo conflicts were brief, involved two individuals and rarely caused serious injury, while chimpanzee males more often attacked in coalitions, including deadly raids on neighbors. In the same study, the more aggressive bonobo males tended to mate more often.

Do bonobos fight with other groups?

Bonobos do not defend fixed territories, and the home ranges of neighboring communities overlap widely. Encounters between groups can start with tension, calls and chases, but they rarely escalate. Instead, members of the two groups often sit near each other, groom across group lines and even travel together for a while. Researchers have recorded bonobos forming friendly ties with individuals from other communities, something almost never seen in chimpanzees.

So are bonobos peaceful?

The best answer is that bonobos are much less lethally violent than chimpanzees and have powerful ways of preventing and repairing conflict, but they are not free of aggression. Their society shows that even close relatives can evolve very different ways of living together. For a full side-by-side look, see chimpanzee vs bonobo, and for their range south of the Congo River, see Where do bonobos live?