THE murder rate among chimps in the wild is similar to the worst parts of drug-ravaged Mexico, according to Scots academics.
A team from St Andrews set out to test whether lethal violence among chimps is natural – or a reaction to human behaviour.
The psychologists, Dr Catherine Hobaiter and Professor Klaus Zuberbühler, concluded that chimps have a inbuilt propensity to kill their own.
Professor Zuberbühler said: “What surprised me personally was that the ‘murder rate’ of chimpanzees is quite comparable to what is found in human societies, around 30 per 100,000 individuals per year.
“Currently, this corresponds roughly to the annual murder rate in Tijuana, Mexico.”
The team carried out the research by studying wild chimps in the Budongo Forest in Uganda.
Their findings shed new light on scientists’ understanding of human violence given that chimpanzees are our closest ancestors in terms of genetics and evolutionary history.
Their work was part of a comprehensive global study which gathered fifty years’ worth of data from 18 chimpanzee and four bonobo communities.
The results found that males were the most frequent killers and often ganged up on their victims eight to one
The study re-examined the hypothesis from pioneering primatologist Jane Goodall’s that chimpanzee violence could be a result of human activities such as destruction of habitat. However, the new research found that human impact has not influenced lethal aggression in chimps.
The murders were more common among larger populations and targeted other males from neighbouring groups. The scientists also discovered that the chimps were killing in order to gain more food and mates.
The overall study from a team of 29 scientists from around the world was led by Dr Michael L Wilson of the University of Minnesota.
Dr Wilson said: “Chimpanzees and bonobos are the two living species most closely related to us of all the animals alive today; we share the most in common in terms of genetics and evolutionary history.
“If we are using chimpanzees as a model for understanding human violence, we need to know what really causes chimpanzees to be violent.
“Based on our results, it’s clear that lethal aggression is something that chimpanzees naturally do. We found that chimpanzees sometimes kill other chimpanzees, regardless of whether human impacts are high or low, whereas bonobos were not observed to kill, whatever the level of human impacts.