Research finds chimp violence is organized

In Yale Daily News
By Alberto Masliah
Staff Reporter
Published Monday, April 4, 2005

Chimpanzees and Al Capone have more in common than opposable thumbs. While a chimp would never be seen gunning down its foes against a brick wall, Yale's anthropology professor David Watts is delving into the arena of organized chimpanzee violence.

Watts has been studying the behavior, ecology and social make up of chimpanzee communities. He researches how they protect their territory, and their women as an extension of that territory. As a relatively new field, essentially started by Jane Goodall in the 1960s, the social behavior of primates is still somewhat of an unknown, Watts said.

The majority of Watts' work is conducted out in the field, where he can roam the territory with the chimpanzees themselves. He said the premier place to analyze chimpanzee communities is Ngogo, which is in Kibale National Park, east of the Democratic Republic of the Congo in Uganda. The Ngogo chimpanzees live in groups three times larger than found anywhere else, Watts said.

"[Ngogo] is a really exciting research place, because there are about 150 chimps in the community," he said.

It is not always happy and peaceful in Ngogo -- the chimpanzees get aggressive with each other. Studying the animals' behavior takes a lot of time, because at first, Watts said, the chimpanzees are terrified of human scientists. The chimpanzees must first become acclimated to having their less furry evolutionary siblings following them around, and humans have to give the chimpanzees nourishment so the animals realize it is beneficial to be followed.

But when they do become comfortable with their new companions, the showdown begins. Watts and his team are trying to determine why that happens.

Chimpanzees roam their land in what anthropologists call a party, a component of the larger community. In this case, Watts said, the community is Ngogo.

Male chimpanzees stay in the community that they are born in, and young females migrate to a community where their mating capacity will be needed. Watts said this behavior is not found in most mammals.

"What people realized at [Ngogo] is that the chimpanzees from one community meet and hear the chimps from neighboring communities and are actually quite good at assessing the amount of chimpanzees in the other group," he said. "If there are too many in the other community, they will do one of two things, either make a show with some noise and charge around for a while and eventually leave, or just leave and concede silently."

This, Watts said, is a way for the community to measure whether or not they would be able to fight off the other community and defend their territory and females. If they do decide to stay and defend their territory, the males will congregate and move toward the edges of their land before charging into the neighboring territory.

"It really all depends on the numbers -- if there are 15 of them and 10 of us, we would probably say 'No. Too much risk,'" Watts said. "But, if there are 15 of us and two of them, we would say 'Let's do it.'"

According to Watt's research, there is one main reason explaining why the chimpanzees interact in this manner, and, as can be seen in human interaction, it stems from the mystery baffling men for ages -- women.

Females are something the male chimpanzees must defend and find, and this may not always be possible without aggression.

"Since this is a group of mammals in which the women move around, and not them, the men have to put up a show to say 'Look, we're tough chimps' and beat each other up because, if they don't prove their strength, how will they show the females that they will be strong enough the protect the infants?" Watts said. "In addition, these females need protection from being attacked."

Since chimpanzees are the only group of animals, other than humans, to have this sort of aggression with neighboring communities, and since they are the only animals where it is the females and not the males that roam about, Watts said violence can erupt which sometimes ends in death.

Students who work with Watts said he is passionate about his work.

"When we were out on the field for seven months at Ngogo, he was out with the chimps from 7 a.m. to 7 p.m. every day of the week," Simone Teelen GRD '05 said. "You could really say that he loves his work, especially since he would only go into town once every two or three months to renew his visa, and that trip really kind of made him unhappy."

Even in the classroom, where students who are not necessarily interested in animals may encounter Watts, students pick up his excitement about chimpanzees.

"You can just tell that he is really interested in what he does, and that is really nice to see in a professor," Kristin Andersen '07, a student in Watts' "Primate Ecology and Social Behavior" class, said. "He always has great pictures of the chimpanzees which makes his class pretty interesting, especially since I have never taken a class that has to do anything with animals."

Watts will be featured in the final episode of the three-part PBS television series "Deep Jungle" on the show "Nature." The series airs April 17, April 24 and May 1.

Courtesy David Watts
Anthropology professor David Watts focuses his research on the communities of chimpanzees in Ngogo, part of the Kibale National Park in Africa.