*To say nothing of sleeping with their friends: Bonobos of both genders are, in a word, rather sweetly slutty. They’ll do it solo or in an erotically contorted, polymorphous cluster. (The original swingers, they’ve been observed in flagrante delicto while hanging from a branch.) Unlike all other primates except you-know-who, they French kiss with osculating abandon and have sex face-to-face. Much of it isn’t exactly sex as we understand it, though, but quick, erotically tinged assurances of affiliation, affection, and conciliation—what one scientist calls “full-body hugging.” De Waal has a standard shibboleth: “The chimpanzee resolves sexual issues with power, and the bonobos resolve power issues with sex.”