Brian Hare, assistant professor of evolutionary anthropology at Duke University, spends several months of the year in the Democratic Republic of Congo, where he studies bonobos. He focuses on their behavior, specifically on how they solve problems and interact with other bonobos. Bonobos are genetically close to humans, yet most people know very little about them. Credit: Vanessa Woods, Duke University

Humans share 98.7 percent of our DNA with chimpanzees, but we share one important similarity with one species of chimp, the common chimpanzee, that we don't share with the other, the bonobo. That similarity is violence. While humans and the common chimpanzee wage war and kill each other, bonobos do not. "There has never been a recorded case in captivity or in the wild of a bonobo killing another bonobo," notes anthropologist Brian Hare.

Hare is an assistant professor in evolutionary anthropology at Duke University. With support from the National Science Foundation (NSF), he and his wife and colleague, Vanessa Woods, studied bonobo behavior at Lola ya Bonobo in the Democratic Republic of the Congo, an orphanage for young bonobos whose parents were killed for the bush meat trade. The war-torn Congo is the only place in the world where these endangered apes can be found.

"We go to this sanctuary and we play these fun problem-solving games with them to just try and get inside their heads and figure out exactly how they think," says Woods. "They're wonderful animals to be related to. It's a shame so few people have heard of them."

Woods is author of the book "Bonobo Handshake," a memoir about her experiences with these peaceful, playful primates, and some of the differences she noted between bonobos and common chimpanzees.

"Chimpanzees can be very empathetic, loving but they also have this darker side. They have war, they kill each other, they beat their females. Bonobos don't really have any of that," explains Woods. "They're different because they've managed to live in a society virtually without violence. How do they do that? Humans, for all of our intelligence and all our technology, we haven't managed to live without war, and so I think that's something very important that bonobos can teach us."

One way bonobos deal with conflict and tension is to have sex. Yes, they're the ultimate hippies--they make love, not war. "Whenever things get tense in the bonobo world, they'll usually have some kind of sociosexual activity and this seems to really help everybody get along. But another one of the ways that they sort of have this peaceful society is they're naturally more tolerant. They share more, and if one of them gets upset, it's not just sex but they can also hug and comfort one another."

In one study, Woods and Hare were surprised when a hungry bonobo opened a gate to share prized treats with another bonobo. "The idea that you would give something to someone else at a cost to yourself, we thought this was something only humans would do."

Bonobos' generous nature likely evolved because they live in an area of the Congo where food is plentiful. They never had to compete with gorillas or kill for a meal like common chimps do.

The females stick together, creating a matriarchal society, and when necessary will gang up on threatening males. "Females will work together to protect themselves from male aggression. So male aggression is just simply not tolerated," says Hare.

With chimps, the most aggressive males tend to team up to dominate females and weaker males. In bonobo society, Hare says it's the mother and son relationship that commands the most respect.

"Basically, bonobos are the ultimate 'mama's boys.' Essentially, it's more like a debutante society where mothers have to introduce their sons into polite society and it's through your mother, as a bonobo, that you will gain access to other females," explains Hare.

How did two such similar species, the bonobo and the common chimpanzee, evolve so differently? Hare says understanding that may shed light on human behavior, considering that we are a lot like both of them.

"Humans are probably the most generous species on the planet," notes Hare, which is very bonobo-like. But like chimps, Hare says, we have that dark side. "Bonobos don't have a darker side. So, although they can't fly to the moon, they don't kill each other. I think they challenge your normal notion of what intelligence is. I think we have a lot to learn from them."