In experiments where chimpanzees could not overcome their aggression in order to cooperate in pulling ropes to access a food-filled box, bonobos in the same setup played, foreplayed, and happily shared the treats. Compared to their warmongering, covetous, calculating chimp cousins, bonobos play nice.

Females bonobos call their own shots, choosing whom they wish to mate with and when. And they’re not very choosy. Females often initiate sex, and unlike chimps and other mammals, bonobos prefer the belly-to-belly, eyes-to-eyes position.

Female chimpanzees mate only during estrus (that is, when they’re in “heat”); female bonobos seem never to glance at their watch. Bonobos seem fully liberated. I call them trisexual; they’ll try anything with anybody, anytime they please.

Caring means sharing, and males in bonobo groups sire equivalent numbers of young. And unlike the politically motivated male coalitions of chimpanzees, a bonobo male’s closest lifelong bond is with his mother.