New research leads authors to conclude that bonobos are no less aggressive than chimpanzees. Nevertheless, there are significant disparities in how aggression manifests between the sexes across the two species: female bonobos are more prone to attacking males, whereas the reverse is true for chimpanzees, where males exhibit greater aggression toward females.
Bonobos (Pan paniscus) and chimpanzees (Pan troglodytes) stand as our closest living relatives. These two species diverged from a common ancestor between 1.5 and 2 million years ago. Their native territories in Central Africa are geographically separated by the Congo River. Scientists hypothesize that the species split occurred when ancestral bonobos crossed the river and became isolated.
Despite their close kinship, chimpanzees and bonobos look and behave quite differently. Bonobos are smaller, possess more slender physiques, and exhibit less pronounced sexual dimorphism than chimpanzees. Female coalitions dominate bonobo communities; this strategy is thought to enable females to exert control over the larger males. In contrast, male chimpanzees occupy the apex of the hierarchy.
In popular culture, largely shaped by scientific narratives, bonobos have acquired an image as the “hippies” of the primate world. They are often perceived as the peaceful “cousins” of volatile and aggressive chimpanzees, purportedly resolving all disputes through sexual contact.
Certain scientists suggest that chimpanzees developed greater belligerence because their side of the Congo River offered scarcer food resources, forcing them into competition with gorillas for sustenance. Conversely, the bonobos’ environment provided greater abundance of food and fewer predators.
Meanwhile, aggression remains a crucial social behavior among apes, serving functions such as territorial defense, mate selection, dominance establishment, and securing resources.
Recently, growing evidence suggests that aggression is certainly not foreign to bonobos either. For instance, a paper published in Current Biology in October 2025 detailed observations by German animal behavior specialists of a brutal attack by five wild female bonobos on a single male within their group.
Findings from a recent study published in Science Advances indicate that bonobos are just as aggressive as chimpanzees, but they target males and females differently in their aggressive encounters.
A team of biologists from Utrecht University (Netherlands) and the University of Antwerp (Belgium) analyzed observational data concerning intra-group interactions within 22 captive groups of chimpanzees and bonobos housed in European zoos: nine chimpanzee groups (totaling 101 apes) and 13 bonobo groups (totaling 88 apes).
At each zoo, researchers spent two to three months stationed near the enclosures, meticulously recording every instance of aggression—ranging from vocalizations to physical violence—that occurred throughout the daily period.
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