…and masturbation. So much of what is unique about our most socialable of species finds expression in aloneness, Jesse Bering in Scientific American:
…[We] are the only primate species that seems to have taken these seminal shedding benefits into its own lascivious hands. Unfortunately, there have been a paltry handful of studies tracking the masturbatory behaviors of nonhuman primates. Although some relevant data is probably buried in some mountain of field notes, I didn’t come across any targeted studies on the subject in wild chimpanzees , and even the prolific Jane Goodall doesn’t seem to have ever gone there. But nevertheless by all available accounts, and by contrast with human beings, masturbation to completion is an exceedingly rare phenomenon in other species with capable hands very much like our own. As anybody who has ever been to the zoo knows, there’s no question that other primates play with their genitalia; the point is that these diddling episodes so seldom lead to an intentional orgasm.In a 1983 study from the International Journal of Primatology , the sexual behaviors of several groups of wild gray-cheeked mangabeys were observed for over 22 months in the Kibale Forest of Western Uganda. There was plenty of sex, particularly during the females’ peak swellings. But just two incidents of male masturbation leading to ejaculation were observed. Yes, that’s right. Whereas healthy human males can’t seem to go without masturbating for longer than 72 hours, two measly cases of masturbating mangabeys were observed over a nearly two-year period.
University College London anthropologist E.D. Starin didn’t have much luck spying incidents of masturbation in red colobus monkeys in Gambia, either. In a brief 2004 article published in Folia Primatologica , Starin reports that over a 5.5-year period of accumulated observations totalling more than 9,500 hours, she saw only 5–count ‘em, five –incidents of her population of five male colobus monkeys masturbating to ejaculation, and these rare incidents occurred only when nearby sexually receptive females were exhibiting loud courtship displays and copulations with other males.
Intriguingly, Starin says that although females weren’t in the immediate vicinity, it is possible that the females could still be seen or heard by the masturbating male while the incident at hand occurred. (In other words, no mental representation required.) In fact, the author’s descriptions of these events strike me as producing accidental, rather than deliberate, ejaculations. Not that they weren’t happy accidents, but still. “During each observation,” Starin writes, “the male sat and rubbed, stretched, and scratched his penis until it became erect, after which additional rubbing produced ejaculate.” I know what you’re thinking: What did the monkeys do with the “product”? Well, they ate their own ejaculate—and in one case, a curious infant licked it off the adult’s fingers. Also, out of the 14 female colobus monkeys observed during this time span, “three different females were observed possibly masturbating” by self-stimulating their genitals—only possibly because none of these episodes culminated in the telltale signs of colobus orgasm: muscle contractions, facial expressions or calls.
So why don’t monkeys and apes masturbate even nearly as much as humans? It’s a rarity even among low status male nonhuman primates that frustratingly lack sexual access to females–in fact, the few observed incidents seem to be with dominant males. And why haven’t more researchers noticed such an obvious difference with potentially enormous significance for understanding the evolution of human sexuality? After all, it’s been nearly 60 years since Alfred Kinsey first reported that 92 percent of Americans were involved in masturbation leading to orgasm.
The answer for this cross-species difference, I’m convinced, lies in our uniquely evolved mental representational abilities—we alone have the power to conjure up at will erotic, orgasm-inducing scenes in our theater-like heads … internal, salacious fantasies completely disconnected from our immediate external realities. One early sex researcher, Wilhelm Stekel, described masturbation fantasies as a kind of trance or altered state of consciousness, “a sort of intoxication or ecstasy, during which the current moment disappears and the forbidden fantasy alone reigns supreme.”
[I]t’s not an uncommon problem for many caretakers of adolescent and adults with mental impairments, whose charges often enjoy masturbating in public and making onlookers squeal and squirm in discomfort. (Not unlike some captive primates housed in miserable conditions such as laboratories or roadside zoos, where self-stimulation sometimes becomes stereotypical.) But one thing that clinicians dealing with this problem may wish to consider is that the individual’s cognitive limitations may not allow them to engage in more “appropriate” private masturbation because of difficulties with mental representation. In fact, frequency of erotic fantasies correlates positively with intelligence. The average IQ of Lukianowicz’s sample was 132. So perhaps public masturbation, in which other people are physically present to induce arousal, is the only way that many with developmental disorders can achieve sexual satisfaction.