Conclusion: Toward a Biology of the Twenty-First Century

The phenomena of nonreproductive and alternative heterosexualities have broad implications for how we look at animal behavior and sexuality in general. Animal social organization and biology do not revolve exclusively around reproduction and, in many cases, appear to be designed specifically to prevent procreation. Although heterosexual mating can (and frequently does) lead to reproduction, this is often an incidental consequence rather than an overriding “goal” (or ultimate “purpose”). Sexuality between males and females assumes a wide variety of forms, many of which necessitate recognizing sexual pleasure as a motivating force.¹⁵⁴ Homosexuality is, therefore, not unique in the animal kingdom by virtue of its “failure” to lead to procreation. It is simply one of many animal behaviors that lack the supposed “purpose” of contributing directly to the perpetuation of the species.

Nor is homosexuality unique in being considered a behavioral “anomaly” by scientists. Because they challenge some of biology’s most fundamental assumptions about how the natural world is organized—while also reflecting stigmatized human behaviors—nonreproductive and alternative heterosexualities have inspired many of the same negative reactions that homosexuality has. As one ornithologist observes, “Until quite recently, [heterosexual] infidelity among wild birds was written off as aberrant behavior, and males were excused as being ‘sick’ or having a ‘hormone imbalance’ or, in one case, being ‘dissatisfied at home.’” Likewise, the Brown-headed Cowbird’s habit of abdicating parental care (by “parasitizing” other species’ nests) was (and in some cases still is) considered particularly “loathsome” by many biologists. As a result, research on this common species has been severely hampered, and information on some basic aspects of its biology and social organization was lacking until fairly recently.¹⁵⁵ Analogously, behaviors such as masturbation, heterosexual trios, interspecies matings, nest desertion, reverse mounting, and forced copulations have all been labeled abnormal, aberrant, unnatural, or anomalous —in some cases as recently as a decade or so ago.¹⁵⁶

Unlike homosexuality and transgender, however, most of these phenomena are no longer pathologized by the majority of contemporary biologists, who now recognize that these behaviors are “normal”—that is, a routine aspect of the social and sexual organization of the species in which they occur. Nevertheless, nonreproductive and alternative heterosexualities continue to evoke profound “puzzlement” regarding their function, which closely parallels the ongoing attempt to find “explanations” for homosexuality. In a recent discussion of alloparenting (helping behavior) in Common Murres, for example, the list of possible “causes” or “functions” of this behavior was virtually identical to those currently invoked to “explain” homosexuality: mistaken identity, heterosexual “practice,” coercion or “manipulation,” hormonal factors, kinship, and nonadaptiveness.¹⁵⁷ Heated debate about their supposed “purpose” continues to envelop the scientific discussion of most other nonreproductive and alternative heterosexualities: adoption, divorce, nonreproductive copulations, infanticide, nest desertion, reverse mountings, sex segregation, nonmonogamous matings, masturbation, multiple copulations, rape, vaginal plugs, reproductive suppression, postreproductive individuals, and harassment of matings all remain “perplexing” and highly contentious phenomena.¹⁵⁸

Even “kisses” have prompted a barrage of functional “explanations.” Unable (or unwilling) to countenance the possibility of pleasure or affection in this “behavior” —much less something more intangible—biologists insist that kisses (even in humans) must be a vestige of ritual food exchange, or olfactory sampling, or have a specific social “function” such as reconciliation or alliance formation,¹⁵⁹ Perhaps this is true—but, as with other social/sexual behaviors, there is so much more to it than this. “The kiss” is a perfect symbol of the limitations of biological reductionism—for even if its origins can ultimately be traced to such functional considerations, something ineffable still remains in the gesture each time it is performed, something that continues to transcend its biological “purpose” and evade “explanation.” Poet e. e. cummings once warned of those who, “given the scalpel,” would “dissect a kiss.”¹⁶⁰ Considering that biologists now have the analytical tools and theoretical frameworks to “dissect” the function of the kiss—and apparently no qualms about doing so—perhaps his admonitions are more than metaphorical.

In 1923 a biologist “explained” polyandry (females mating with more than one male) in phalaropes (a type of sandpiper) as being caused by the “deranged sex organs” of female birds, whose “wanton” behavior was “forcing polygamy on the race.“On discovering this historical “explanation” more than half a century later, one ornithologist conceded that scientific theories often reflect “the passions and prejudices of the time,” adding, “Half a century hence, our successors will no doubt find similar amusement in ideas devolving from our present ignorance.”¹⁶¹ Much of the “present ignorance” of biology lies precisely in its single-minded attempt to find reproductive (or other) “explanations” for homosexuality, transgender, and nonprocreative and alternative heterosexualities. In the next chapter we’ll explore how biology can take a first step into the twenty-first century—by reconciling itself at the most fundamental level to the existence and apparent “purposelessness” of this broad panoply of behaviors, sexualities, and genders in the natural world.

The kiss: two male Chimpanzees (left) and female Squirrel Monkeys (right) kissing

Chapter 6