|Compared to the chimpanzee, and to most other primates, the period of sexual receptivity of bonobo females is drastically extended.|
|Because the vulva in ventrally directed, the genital anatomy seems adapted to face-to-face copulation, a frequently adopted position.|
|Characteristic of the species are lateral genito-genital rubbing
movements between females mounted in a ventr-ventral position, one
female carrying the other [...].|
The bonobos were observed for nearly 300 hours by the author [...]
[...] Sociosexual contacts of adults and adolescents with the infant frequently were initiated by the infant herself. [...]
Two oral sociosexual patterns occurred almost exclusively in the group of juveniles.
|One pattern is the mouth-to-mouth-kiss, which in the bonobo has strikingly sexual character [...]|
|The second pattern is fellatio, that is, one partner taking the penis of another in the mouth.|
These two sociosexual patterns frequently occurred in the context of rough-and-tumble play. [...]
[...] Males more often initiated contact with younger partners than did females. [...] Isosexual initiatives, finally, were mainly directed at partners of the actor's own or a younger age class. [...]
All that can be concluded is that [...] no evidence was found that potentially fertile partner combinations engaged in sociosexual behavior more often than did infertile combinations. [...]
[...] These contacts appeared to reduce the tension an to allow for food sharing. [...] The interaction could even take the form of an exchange, e.g., a female presents to a male who is holding a large bundle of branches and leaves and takes the entire bundle out of his hands immediately following sexual intercourse. [...]
The majority of instances of genital massage, for instance, followed aggressive incidents in which the adult male had chased one of the adolescent males. After a couple of minutes, the younger male would return to the aggressor to present his genitals.
Humans' close primate relative, the bonobo, shows a large amount of intergenerational sexual behavior. As in other primates, this behavior can partly be explained as an exploration and preparation for adult reproductive sex.
Yet, the specific context in which intergenerational sex occurs among captive bonobos suggests an important additional function, which also applies to this species' intragenerational sex. Sociosexual behavior occurs in all possible age and sex combinations as a mechanism of reassurence and appeasement. This function of sexual behavior patterns does not interfere with the fertilization function of these patterns, because males appear to limit penetration and ejaculation to contacts with mature females.
Both in the wild and in captivity, the bonobo (Pan paniscus) exhibits a surprising variety of sexual and erotic behavior patterns. A quantitative study of 10 captive members of the species kept at the San Diego Zoo investigated the role of sexual and affiliative behavior patterns in the regulation of social tension.
These behavior patterns increased in frequency at moments of competition, such as at feeding time, and following aggressive incidents in the colony. Sociosexual behavior occurred with equal frequency and equal intensity in all age and sex combinations possible. Intergenerational sex was part of this general pattern.
The bonobo's sexual reconcilation and reassurance patterns were described and contrasted with the behavior of the chimpanzee, which virtually lacks this nonreproductive function of sexual behavior. The evolutionary origin of this difference was sought in heterosexual bonding among bonobos in their natural habitat.