Chimps' True Nature is Violent: Like Humans, These Primates Kill Their Own

Chimpanzees are one of the most closely related species to humans still living on this planet. Now, it turns out that we may share something more in common. Scientists have found that humans and chimps are some of the only species to engage in coordinated attacks on other members of the same species and they may just have an explanation for why that is.

In the past, researchers have thought that there were increased gains and benefits to killing off competitors. More specifically, getting rid of the competition can open up access to new resources, such as food or mates. Yet another theory holds that the strife seen between chimps is actually a result of human impact on the animals, such as habitat destruction.

"This is an important question to get right," said Michael Wilson, lead author of the new study, in a news release. "If we are using chimpanzees as a model for understanding human violence, we need to know what really causes chimpanzees to be violent."

In order to learn a bit more about whether or not chimp aggression is natural for the species, the scientists assembled data sets spanning five decades of research gathered from 18 chimp communities. All communities experienced varying degrees of human influence and in all, the data included 152 killings by chimpanzees.

"Humans have long impacted African tropical forests, and one of the long-standing questions is if human disturbance is an underlying factor causing the lethal aggression observed," said David Morgan, co-author of the new study. "A key take-away from this research is that human influence does not spur increased aggression within or between chimpanzee communities."

In fact, the researchers found that the majority of attackers and victims of attack are male chimpanzees. This, in particular, is consistent with the idea that these violent acts are driven by adaptive fitness benefits rather than being driven by human impacts.

"The more we learn about chimpanzee aggression and factors that trigger lethal attacks among chimpanzees, the more prepared park managers and government officials will be in addressing and mitigating risks to populations particularly with changing land use by humans in chimpanzee habitat," said Morgan.

The findings are published in the journal Nature.