females of all ages, from adolescent to very old, but if an older and a younger female are interacting, often the younger female will be on top. Sexual activity may also be more common when the females are of different ranks. Homosexual interactions are often initiated with a characteristic series of “courtship” signals: approaching the partner and peering closely, standing on the hind legs and raising the arms over the head while making eye contact, and/or touching the shoulder or knee while staring. Among captive Bonobos, partners may also use a highly developed “lexicon” of manual gestures to help negotiate the position(s) to be used in sexual interactions (see pp. 66–69 for more detailed discussion).
Females may have multiple sexual partners. In one troop containing ten females, each female interacted sexually with five other females on average, and some had as many as nine different partners. Group sexual activity also occasionally takes place, with three to five females simultaneously rubbing their genitals together. Some females are considered especially “attractive”—usually because of the shape, size, and coloration of their genital swellings—and individuals may have preferred partners that they tend to interact with more often. In fact, females typically form strongly bonded, enduring relationships with one another that are fostered by sexual interactions and include such activities as mutual grooming, play, food-sharing, and alliance-formation (often for challenging males). Females generally prefer each other’s company, and their same-sex bonds form the core of social organization. In addition, when new females (usually adolescents) join a troop, they often pair up with an older female with whom they have most of their sexual and affectionate interactions. These bonds need not be exclusive—either party may have sex with other females or males—but such mentorlike pairings can last for a year or more until the newcomer is fully integrated into the troop. In this species, a sort of homosexual “incest taboo” is in effect for these pair- bonds: most females are unrelated to the Bonobos in their new troop, but those who are related are not chosen as special partners. Some homosexual activity does, however, occur between mothers and their daughters.
Male Bonobos also have a wide variety of homosexual interactions. Sometimes, two males mutually stimulate each other’s genitals using a face-to-face position similar to GG-rubbing: one male lies on his back and spreads his legs while the other thrusts on him, rubbing their erections together (in this and all other male homosexual activity, anal penetration is not involved). If there is an age difference between partners, often the younger male will be on the bottom. Occasionally, two males hang from a branch facing each other and engage in what is known as PENIS FENCING, swinging their hips from side to side as they rub their erect penises on each other or cross them as if they were fencing with swords. Another activity is RUMP RUBBING, in which two males stand on all fours in opposite directions, pressing their buttocks against each other and mutually rubbing their anal and scrotal regions. Both males often have erections. Males also mount each other from behind and either mountee or mounter may make thrusting movements. Sometimes the males switch positions, and the mounter may scream or grin in sexual arousal as in lesbian or heterosexual interactions. Bonobo males have also been seen standing on their hind legs, one embracing the other from behind. Other sexual activities include oral sex, or fellatio, in which one male sucks another’s penis at the initiation of either partner (usually seen only in younger males). Manual stimulation of the genitals by a partner also occurs: typically an adolescent male spreads his legs and presents his erect penis to an adult male, who takes the shaft in his hand and caresses it with up-and-down movements. Younger males (and occasionally females) also sometimes give each other openmouthed kisses, often with extensive mutual tongue stimulation. Although males do not appear to form pairlike bonds with sexual partners (as do some females), occasionally two or three males are intimately associated as companions, constantly accompanying each other and foraging together.
Nonreproductive and Alternative Heterosexualities
Variety, flexibility, and frequency of sexual interactions are not limited to contact between Bonobos of the same sex—heterosexual activity is replete with nonreproductive behaviors. Rump rubbing, fellatio, and manual stimulation of the genitals by either sex (including fondling of the scrotum) are all aspects of male-female sexual interactions. In addition, females occasionally mount males from behind (REVERSE mounts), and heterosexual copulation often does not involve penetration and/or ejaculation, but simply mutual rubbing of genitals. Both male and female Bonobos also masturbate (males sometimes using inanimate objects to stimulate themselves). Group sexual activity occurs as well, often with one individual thrusting against a pair who are copulating, and individuals may participate in several bouts of heterosexual activity in rapid succession. Sometimes, because of the frequency and persistence of sexual invitations—often associated with begging for food—individuals (especially males) may even become annoyed and try to avoid further heterosexual interaction. In addition, females occasionally cooperate with one another in harassing and attacking males, in some cases causing severe injuries by holding a male down and biting his ears, fingers, toes, or genitals.
Bonobos mate during all phases of a female’s sexual cycle, and about a third of copulations occur during periods when fertilization is unlikely or impossible. Mating also takes place during pregnancy, sometimes as late as one month before delivery. Both adult males and females interact sexually with adolescents and juveniles (three- to-nine-year-olds). In fact, young females go through a five-to-six-year period sometimes referred to as ADOLESCENT STERILITY (although no pathology is involved) during which they actively participate in heterosexual mating (often with adults) but never get pregnant. Sexual behavior between adults and infants of both sexes is also common—about a third of the time it is initiated by the infant and may involve genital rubbing and full copulatory postures (including penetration of an adult female by a male infant). Another form of nonreproductive sexuality involves contact with other species: younger male Bonobos have occasionally been observed engaging in playful sexual interactions with redtail monkeys
*Blount, B. G. (1990) “Issues in Bonobo (
*Enomoto, T. (1990) “Social Play and Sexual Behavior of the Bonobo
*Furuichi, T. (1989) “Social Interactions and the Life History of Female
