Chimpanzees pick over the dead body following a brutal attack at the Fongoli Savanna Chimpanzee Project in Senegal Pruetz, JD, Ontl, KB, Cleaveland, E et al. Int J Primatol (2017)

Anthropologists have recorded a grisly attack on a West African chimpanzee that was beaten and eaten by his own tribe in Senegal.

The brutal incident is one of only a handful of recorded cases of chimpanzees turning on their own. The attack took place after former alpha male, Foudouko, had been overthrown, spent several years on the periphery of the social circle, then tried to reintegrate with his community. Anthropologists got close enough to record the aftermath of the episode, when his dead body was repeatedly beaten by a young adult male and an older female, the latter “cannibalis[ing] the body”, according to the report in International Journal of Primatology.


One key reason for the event may be the disproportionate number of males in the group - typically, there are more adult females – and this kind of imbalance increases the need for competition for reproduction rights. Jill Pruetz, anthropologist at Iowa State University and co-author on the paper, referred to Foudouko’s initial reign as tyrannical in an interview with the New Scientist. He was ultimately pushed out as the alpha - and the group as a whole - after he refused to cut ties with his injured beta male. He was only accepted back in 2013 after the beta male regained his position. Foudouko failed to regain his own authority after years spent living on the fringes of the mini society and a number of the males took umbrage with his presence, repeatedly trying to chase him off.

Subscribe to WIRED

Read next This is what life on Venus might look like – and how we’ll find it This is what life on Venus might look like – and how we’ll find it

In this context, Foudouko may have been perceived as an outsider to some extent, and one who was repeatedly attempting to antagonise the hierarchy.

When the Fongoli Savanna Chimpanzee Project team came across his deceased body after hearing screams, Foudouko's injuries were horrendous: cracked ribs, cuts on his fingers, a bite on his right foot, a huge cut on his back and a ripped anus, reports the New Scientist. They speculate that some of the chimpanzees held down the body while others attacked. Pruetz and her team witnessed the chimpanzees continuing to abuse the body after he was dead.

“It was striking,” Pruetz said. "The female that cannibalised the body the most, she’s the mother of the top two high-ranking males. Her sons were the only ones that really didn’t attack the body aggressively.”

"When the team came across the body, injuries included cracked ribs, cuts on his fingers, a huge cut on his back and a ripped anus"


She concluded by suggesting the beta male might be next in the firing line, after being treated in a similarly dismissive way of him after the attack.

The story comes two years after a study published in Nature suggested aggression among chimpanzees was not the result of human influence - as has been argued in the past - but a natural result of competition. That study looked at data gathered from 18 chimpanzee communities, across 426 collective years of observation. They found repeated incidents of killings taking place while male chimpanzees were patrolling their community borders, and it was discovered deaths correlated to the number of males in a community and the local population density, as was the case with this most recent incident in Senegal.

Human intervention, either through the introduction of food or changing of the habitat, did not appear to be a factor. In the case of Foudouk, a certain degree of human intervention does appear to be at fault, however. Pruetz, who has been studying the community since 2001, told the New Scientist she believed poaching of female chimpanzees may be behind that gender imbalance that ultimately upped the competition stakes within the Fongoli Savanna Chimpanzee Project community.