Homosexual consortships (pair-bonding with sexual activity) among Japanese Macaques, for example, virtually never occur between mothers and daughters or sisters. In contrast, heterosexual brother-sister or mother-son relations, while not common, are much more prevalent than homosexual incest in this species. Interestingly, aunts and nieces among Japanese Macaques do not generally recognize each other as kin—when intervening on behalf of individuals during aggressive encounters, for example, aunts do not assist their nieces any more often than do nonrelatives, and significantly less often than do mothers, grandmothers, and sisters. Consequently, some blood relatives are able to form consortships with one another: about a third of all aunt-niece dyads interact homosexually. In other words, Japanese Macaques have an overall pattern of incest avoidance unique to homosexual relations, within which apparently incestuous aunt-niece pairs are “permitted” because such partners do not count as kin in the larger social framework.
In Hanuman Langurs, both heterosexual and homosexual incest taboos are in effect, but with slightly different restrictions. Heterosexual incestuous relations of any kind are generally avoided; sexual activity between mothers and daughters is also “prohibited” (accounting for only about 1 percent of all homosexual mounting). In contrast, half sisters (females with the same mother but different fathers) are “allowed” to have sexual relations with one another—and in fact, more than a quarter of all mounts between females occur between half sisters. In Bonobos, incestuous relations between females also generally appear to be avoided: when females immigrate into new troops as adolescents, they are usually unrelated to most of the other troop members, but sexual activity is not practiced with those females to whom they are related.68
These examples demonstrate that, at least in some nonhuman primates, homosexual (as well as heterosexual) relations are subject to various social prohibitions regarding choice of appropriate partners, especially where relatives are involved. These choices are not due to instinct (i.e., avoidance of an activity that would yield harmful genetic effects), because no offspring result from such relations, and because not all incest taboos are identical. Nor are they simply a “carryover” from heterosexual taboos, because same-sex and opposite-sex relations often have different prohibitions. Crucial distinctions exist between species, populations, and even between heterosexual and homosexual activity in the same species, concerning “allowable” incestuous relations—differences that cannot be attributed solely to biological (genetic) factors. Only some relatives actually “count” as related for the purpose of incest taboos, and which individuals are “tabooed” is, to a large extent, arbitrary. In other words, primates must learn what sort of kinship system(s), if any, govern sexual associations—both homosexual and heterosexual—in their social group. While the occurrence and expression of same-sex activity in these animals very likely has an instinctual or genetic component as well, homosexual relations exhibit important “cultural” characteristics that probably involve a high degree of social learning. “Taboos” exist in animals, and homosexuality is one area where such prohibitions manifest themselves in particularly compelling ways.
Ritual
Where do human rituals such as taking an oath come from? In a fascinating study of Savanna Baboon social systems, primatologists Barbara Smuts and John Watanabe offer a startling answer: they suggest that such symbolic gestures might be traced to the ritualized homosexual activities that take place between male Baboons. 69 As part of their social interactions, male Savanna Baboons perform a variety of formalized sexual and affectionate behaviors with each other, most notably “diddling,” that is, fondling of the penis and scrotum. Other ritualized homosexual activities include mounting; grabbing, fingering, and nuzzling of the rump; kissing and nuzzling of the genitals; and embracing and kissing on the head or mouth (similar activities are also found in a number of other primates, including Common Chimpanzees, Bonnet Macaques, and Crested Black Macaques). Although these behaviors undoubtedly have an affectionate or “pleasurable” tactile component as well as a sexual dimension, they have also been characterized by some scientists as “greetings” interactions, and it is thought that they may serve to negotiate and solidify cooperation between males as well. Indeed, two males sometimes pair up and form a stable “coalition” with each other in which their mutual defense and aid is symbolized by the reciprocity of their ritual sexual exchanges with one another. Smuts and Watanabe suggest that sexual gestures such as diddling, which involve one male placing his most vulnerable and intimate organs literally in the hands of another, are in a sense a prototypical form of oath-swearing: one male, by his actions, is indicating his trust and commitment to cooperate with the other.
Two male Bonnet Macaques embracing each other in a “greeting” gesture. The male on the left is fondling the scrotum of the other male with his right hand, an activity also found in male Savanna Baboons, where it is known as “diddling.”
But what does this have to do with human rituals of oath-taking? In our society at least, oaths usually involve gestures such as raising of the right hand, crossing the heart, or perhaps even placing the hand on a Bible, but certainly nothing so forward as fondling of the genitals. Surprising as it may seem, though, Smuts and Watanabe present some intriguing clues that gestures similar to the ritual homosexual activities of Baboons (and other primates) may in fact have been a part of human oath-taking at one time and are even still used in some contemporary cultures. In a number of Australian Aboriginal tribes, for example, holding of the pe- 1 nis is traditionally used as a gesture to express male allegiance and cooperation, as well as a ritual part of resolving disputes between “accused” and “defending” parties. Among the Walbiri and Aranda people, when different communities get together or when grievances need to be settled in formal “trials,” men participate in what is known variously as touch-penis, penis-offering, or the penis-holding rite. Each man presents his semi-erect organ to all the others in turn, pressing it into each man’s palm and drawing it along the length of the upturned hand (held with the fingers toward the testicles). By offering and grasping each other’s penis—said to represent “paying with one’s life”—the men make an avowal of mutual support and goodwill between them, or symbolize and solidify the agreement they have reached during the settling of a dispute. A similar gesture involving stroking of the genitals and/or scrotum is used as a greeting in some New Guinea tribes such as the Eipo and Bedamini.70
Closer to home, there is historical—even biblical—evidence that similar rituals may have been a part of the Judeo-Christian and Euro-American heritage. Ironically, the book that is today used in so many of our own oath-swearing ceremonies contains within it an allusion to these earlier practices. In Genesis 24:9 there is a reference to the servant of Abraham swearing an oath by placing his hand under his master’s “loins.” Moreover, according to the Oxford English Dictionary the words testify, testimony, and testicle are probably all related, sharing the common root testis, which originally meant “witness.” Although these connections are somewhat speculative, they suggest a line of continuity between ritualized homosexual behavior in primates and human social rituals such as oath-taking. As Smuts and Watanabe point out, notions of truth and sanctity as expressed by the human ceremonies are vastly different from those of Baboons (if present at all in the nonhuman context). Nevertheless, the forms of these rituals—and their social outcomes—are strikingly similar.