Chimps Show Lethal Side
In a cooperative venture aimed at understanding the most uncooperative of acts, researchers studying different African communities of wild chimpanzees have pooled their data and found that the apes sometimes kill each other nearly everywhere they’ve been studied.
Chimp homicides occurred most frequently in groups with the most adult males, anthropologist Michael Wilson of the University of Minnesota in Minneapolis reported April 12 at the American Association of Physical Anthropologists’ annual meeting.
Wilson persuaded researchers at 10 wild chimp sites, containing a total of 17 communities, to contribute their findings on lethal attacks collected over the past several decades.
Chimps spend most of their time in peaceful pursuits, such as playing, foraging and grooming each other. Yet researchers, beginning with Jane Goodall more than 40 years ago, have described occasional chimp homicides. Some investigators have speculated that these animals get lethally riled up by human intrusions, such as deforestation, hunting and feeding of chimps by eco-tourists.
But the new study found that chimp communities with the most documented killings had no or only rare encounters with humans. Groups of males carried out most killings, and most victims were male adults and infants in neighboring communities.
“The new findings suggest that killing is an evolved strategy, mainly for adult males to eliminate rivals and competitors for mates,” Wilson said.
Researchers documented 86 cases of chimp homicide, either by observing lethal attacks in person or finding dead bodies with fresh wounds, often after hearing attacks in progress.