Bonobos have long had a reputation as the hippies of the ape world. Famously nonaggressive, their matriarchal societies, strong female friendships and largely vegetarian diets have stood in stark contrast to the macho bloodlust of their two closest relatives — chimpanzees and humans.
Until now.
New research published in Current Biology upends a deep-seated understanding about bonobos and, as a result, could change our understanding of how early humans lived, worked and ate.
Female bonobos, it turns out, aren’t just fruit-eating pacifists, but vicious hunters.
Bonobos are as closely related to humans as chimps. New evidence that female apes are the primary hunters in their troops could radically alter the prevailing model of early human societies, in which men felled big game like bison and antelope, while women engaged in less risky tasks like gathering berries and nuts.
“It really does challenge this idea of the male warrior — that the male hunter is the ancestral model that we should be leaning on,” said Jake Brooker, a primatologist at Utrecht University in the Netherlands, who was not involved in the work.
Notions of an ancestral “man the hunter” have long been kicked about by anthropologists and ethnographers. The idea was largely based on studies of living hunter-gatherer societies, like the San people of southern Africa, in which men dominate hunting and fighting.
“If people go out and study a tribe in the Bornean jungle, if they go to Bushmen,” said Gottfried Hohmann, a primatologist at the Max Planck Institute of Animal Behavior and lead author of the study, “it is usually men that are more active in hunting.”
Researchers found further fodder for the theory in our closely related primate cousins, chimpanzees. Male chimps are deeply territorial, form strong bonds with other males and hunt in organized groups to take down prey or fight competing troops.
The man-the-hunter narrative seemed robust until bonobos “just kind of screwed it all up,” said Dr. Brooker. Male bonobos are subservient, wield little power in their troops and have few friends other than their mother or siblings.
Both bonobos and chimpanzees hunt, supplementing their diet of fruit and herbs with the occasional captured monkey or small deer. While male chimps are the clear hunters in their troops, the hunters in bonobo groups had largely remained a mystery.
The new work, derived from data collected over nine years, centers on two groups of wild bonobos living in the Salonga National Park in the Democratic Republic of Congo, a remote region in the heart of the second-largest rainforest on earth. To get there, researchers had to board a charter plane to a small airstrip in the dense Congo jungle, hike nearly 20 miles through bush, savanna and swamps and cross a large river by dugout canoe.
“You feel like a little insect,” said Dr. Hohmann. The tall jungle canopy stifles the daylight and it can often feel claustrophobic. “It is dark. It is wet. It is smelly. So, it is not for everyone.”
The researchers documented hunts between February 2014 and August 2023, often waking up around 2 a.m. to watch the bonobos descend from their treetop nests and commence a hunt.
The scientists focused exclusively on activity where they could discern the primary hunter, creating a catalog of 158 such hunts. Their data revealed that females led a majority of hunts across both troops: 99 of the hunts were led by females, while only 59 were led by males. It was typically the older, more dominant females that led the way.
“It can be a pregnant female — it can even be a female who carries a young infant still suckling,” said Barbara Fruth, a behavioral ecologist and bonobo expert at the Max Planck Institute and an author of the study.
The most common prey was the red colobus monkey, the killing of which required coordinated teamwork from the bonobos. As many as 20 female bonobos were recorded descending on equally large groups of monkeys.
Male bonobos are larger and stronger than females, but they are not the dominant members of the troop, showing that the ability to hunt is not necessarily about big muscles or a tolerance for risk.
Dominant female bonobos decide how the hunt is shared, doling out meat as a way to form alliances, Dr. Fruth said. Males, on the other hand, risk having their kill stolen by a more authoritative female.
The study, researchers said, may indicate that what is true today about modern human societies may not have been true about our ancestors millions years ago.
“Our two closest cousins have this completely opposite approach to how they live their lives,” said Dr. Booker. “If we’d have studied bonobos from the start, what would we think now?”
