The Demonic Ape - questions and answers

How are chimpanzees similar to humans?

Chimpanzees and humans share many common traits. Genetically chimps share over 98% of their DNA with humans. They are our closest living relatives, and we share a common ancestor with them from over 5 million years ago. From this ancestor both humans and chimpanzees diverged to evolve into the separate species you see today. Chimpanzees also make and use tools – a trait previously thought to be solely human. They also have a primitive form of language and appear to use vocalisations to communicate in a sophisticated manner. Recent research by Professor Sarah Boysen suggests that chimpanzee vocalisations are 'word-like'. Chimpanzees also exhibit culture – the handing down of learned traits from generation to generation. Males of both species also share similarly violent traits.

Are chimpanzees the only primates that kill their own kind?

The only other primates that kill their own kind are in fact, us. Humans and chimpanzees show a common aggressive tendency and will actively seek out and kill members of their own species. Chimpanzees and humans are the only other species that, out of 4000 other mammal species and 10 million other non-mammal species, have been observed to hunt and kill members of a rival group. Explanations for this behaviour are fascinating and covered in depth in Professor Richard Wrangham’s book, “Demonic Males”.

Why do Chimpanzees kill their own kind? Is it for food, or just to reclaim territory?

It is thought that male chimpanzees kill other members of their species in order to extend their territory size to gain access to more fruit, and increase the number of females that might enter their group.

What is the Demonic Male hypothesis?

The demonic male hypothesis was put forward by Richard Wrangham (Harvard University) to explain the violent behaviour seen in both male chimpanzees and male humans. The hypothesis suggests that as only the males of both species illicit this behaviour, that this propensity for male violence has been inherited from our common ancestor 5 million years ago.

Why do scientists think that Frodo is so much more violent than the other chimpanzees?

Frodo is the dominant alpha male of the longest studied group of wild chimpanzees in the world. He is now highly habituated (familiar with human contact) and shows no fear of human beings. He has always ruled his group with force and maintains his high status in the group as a result. His violence has always been apparent - even as a youngster he used to throw rocks at Jane Goodall. His escalating violence as an adult is probably due to a combination of habituation, his alpha status and increased competition for resources as a result of increased human encroachment on his dwindling habitat.

Are there other signs that chimpanzees are stressed by human encroachment other than their aggression?

Chimpanzees in different parts of Africa (Uganda particularly) show other, more shocking signs of increased competition between humans and chimpanzees. Many chimpanzees are missing a foot or a hand as a result of snaring. The chimpanzees of Gombe have also been affected by many serious respiratory infections believed to have been transmitted from humans. In recent years this has been of considerable concern to the researchers at Gombe who are now implementing ways of reducing human contact.

Are there other places except Congo where the chimps aren’t violent at all?

The chimpanzees at Prof Christophe Boesch’s research site on the Ivory Coast appear to be less aggressive towards people. This might be due to the fact that they are less habituated and that the forests are more pristine.