‘The most violent attack ever documented’: Five female bonobos kill a male, challenging beliefs about the species’ peaceful nature (Javier Salas, El País, Oct 22 2025)
"The assault lasted 25 excruciating minutes for Hugo, who tried to cover his head while the entire clan watched without intervening, including some of his relatives.
“The females jumped alternatingly on Hugo’s body, stomping on his back and biting his head, legs, neck, fingers and toes.
One female bit off a part of Hugo’s ear, two others engaged in genito-genital rubbing with each other on top of him.
One of the perpetrators bit into his foot and chewed on the removed tissue, then bit his testes,” the scientists who documented the case describe in detail. (…)
Male chimpanzees maintain strict hierarchies and form long-lasting bonds with each other, while using violence against females to secure offspring.
Bonobos, by contrast, live in a matriarchy: females dominate the group through alliances, reinforced by behaviors such as mutual genital rubbing, which is largely about pleasure. (…)
Males are larger and stronger, yet it is the females who wield violence as a tool of social control.
Perhaps that is why it has gone largely unnoticed.
“It reflects a very male-centric view,” admits Martin Surbeck, from Harvard University, who has also worked with the bonobos of Lui Kotale, in Salonga National Park, but did not participate in this study.
Surbeck published a study in April that reviews 30 years of observations to understand the power of bonobo females.
Eighty-five percent of violent coalitions are led by females seeking to keep males in check, demonstrating that their ferocity is clearly functional: to prevent them from becoming like chimpanzees.
In some communities, females win 100% of conflicts, showing that their dominance is structural.
“The power of these female coalitions is one of the main mechanisms that reverses the power dynamics between the sexes within bonobo groups,” Surbeck added via email.
When female bonobos form aggressive alliances to exert social control over males, they demonstrate that power can be derived not from physical strength, but also from social support.
This is where the attack by the five females on Hugo begins to make sense.
According to primatologists monitoring this community, a couple of days earlier, Hugo had acted aggressively toward the infant of the youngest attacker, Bella (15 years old).
Infanticide is a common male strategy in many species to ensure reproductive success: a male fathers offspring once the female is no longer caring for the children she had with others.
“Bonobo females, however, have managed to reverse this trend, which chimpanzees do, thanks to an unusual cooperation between them,” explains Pashchevskaya, “and they even attack males who misbehave with their young.”
“Extreme violence would be better explained as a response to the extreme threat: infanticide,” summarizes the lead author of the case now detailed in Current Biology."
