I’ll bet you a beer you don’t know the species with DNA most closely matching humans.

The answer is the bonobo at 99.6%. (I’ll take a Bass Ale, thanks.) They look like chimpanzees, but behave quite differently. You could call chimpanzees the evil-parallel-universe versions of bonobos (minus the goatees). Chimps can be warm and loving, but they also maim, rape and kill each other. According to Vanessa Woods, however, bonobos cooperate rather than compete, literally preferring to make love rather than war.

Woods’ book Bonobo Handshake chronicles her study of bonobos in the Congo. She also describes the political backdrop of humans who do a lot of maiming, raping and killing of their own. (It’s like Jane Goodall meets Hotel Rwanda.) And don’t think that can’t happen here. The college students in the Stanford Prison Experiment, normally docile in their native environment, went Lord of The Flies in only six days.

Darwin himself wondered how good ever evolved. When others steal and kill, altruistic behavior is a sucker’s ticket to extinction. Darwin speculated some group-level selective advantage; others later developed models of nepotistic “kin selection.” But you still had the problem of free riders sleeping on the genetic couch of the altruists and outbreeding them. Enter George Price, who developed a mathematical model demonstrating how altruistic traits could be passed on genetically. Unfortunately, this convinced him selfless altruism didn’t exist.  He later gave away all his money, and ultimately committed suicide.

Today, people distinguish between “biological” altruism (evolutionary self-interest) and “psychological” altruism (intentional and empathetic). Getting back to bonobos, Woods saw one put herself between a fallen comrade and a gun, leading her to believe bonobos are capable of psychological altruism. She helped conduct experiments suggesting that bonobos trust and unselfishly share to a degree that chimpanzees would metaphorically fling feces at in contempt.

I was disappointed when Woods suggested an environment of plentiful food, rather than harsh competition, may have shaped the bonobos’ character.  Still, if the cruelty that comes so easily to us is absent in our closest relatives, further study seems like a good idea.