In their ancestral lands in the far north of the Kunene River region of Namibia—a country bordered by Angola above, Botswana to the east, South Africa below, and first the Namib Desert and then the Atlantic Ocean along its western edge—live the Himba. They are the region’s last seminomadic people, pastoralists who grow calabash, millet, and maize but also depend on the milk and meat of the goats, sheep, and cattle they raise. The Himba live in compounds of two dozen or so people, in huts of mud and cow dung, around which they build fences of mopane wood to contain their livestock. But they move often, setting out whenever grazing conditions decline. Only an estimated 30,000 to 50,000 Himba remain in Northern Namibia and across the border in Angola, after surviving near extermination by German colonizers in the early 1900s, intermittent years of devastating drought, and the bloody Namibian revolution of the 1980s.
Relatively isolated in the remote, mostly desert environment where they eventually settled after so much upheaval, protected by the Namibian government, and proudly attached to their ancestral traditions, the Himba have managed to preserve many of their long-standing cultural practices, even as they adapt to change by allowing themselves to be photographed (sometimes for money), journeying to shop at supermarkets, and sending their children to schools. Every morning Himba women cover their skin and long plaited hair in otjize, a vivid orangish-red mixture of fragrant herbs, butterfat, and ochre—a naturally occurring mineral from the region’s soil—that has antimicrobial properties useful in an arid climate where bathing is rarely possible, and that the Himba believe makes them beautiful. Aside from this layer of otjize, women leave their breasts exposed. They wear fabric or cowhide skins around their waists, don leather headdresses that vary according to their age and social status, and carry their babies on their backs in slings made of wood and animal hide. Himba women wear heavy, decorative stacked bands of copper, iron, bone, and sometimes PVC or barbed wire around their wrists. They wear similar bands stacked from their ankles to their lower shins, too, which also serve to protect them from snakebites.
Himba women generally spend their days milking and tending to goats and cattle, gardening, collecting water and firewood, cooking, and repairing and building the structures around the encampment. They are almost always in close contact with their babies; older toddlers who have been weaned and children are also somewhat dependent upon one another, playing as a group, with the older kids informally teaching and tending to the younger ones. Livestock are in many ways the center of Himba life. In the twenty-three Himba compounds the UCLA anthropologist Brooke Scelza studied in the Omuhonga Basin area, about one hundred miles from the main district town of Opuwo, women often remain at the main camp while men make excursions to remote cattle posts, where they may stay for weeks and sometimes even months at a time.
Long-term physical separation of spouses is a fact of Himba life. So is infidelity, which Scelza, like many anthropologists and sex researchers, prefers to call “extra-pair partnership,” “multiple mating,” or “extra-dyadic sexuality.” It is not uncommon for a married Himba man to take one of his several wives with him to the cattle stations or to have a girlfriend there (unmarried men spend time at the cattle stations as well). And many of the Himba wives who stay behind in the main camp take lovers while their husbands are away. This should come as no surprise given that infidelity is a cultural universal—anthropologist Helen Fisher, who began studying it in the 1980s, told the New York Times in 1998, “There exists no culture in which adultery is unknown, no cultural device or code that extinguishes philandering.”
While they are not unusual in that they cheat, the Himba are remarkable in their relative openness about their extra-pair involvements. Married people discuss their “affairs” more freely among themselves than we do, certainly, and also speak about them with anthropologists like Scelza, probably because there is little reason not to: the Himba are one of the rare cultures where there is not the kind of taboo against adultery that we have and might expect to be “universal.” Spouses expect a degree of consideration from each other, to be sure, and there is a code that governs how lovers are to behave—“I don’t like it when her boyfriend is here in the morning when I come back from being away” is the gist of what one Himba man told Scelza. As Scelza explained to me, “There’s a framework, and there has to be respect.” But affairs are an open secret, or perhaps more accurately a non-secret. More extraordinary still, unlike many societies where only male infidelity is tolerated, women too are relatively open about having affairs. Among the Himba, female infidelity is widespread, openly acknowledged, and in many ways a boon to the women who practice it. In fact, Scelza discovered that through an unapologetic embrace of female “adultery”—a practice we Americans are so accustomed to thinking of as inherently risky and even perilous for women, or as a sign that something is undeniably “wrong”—Himba women actually improve their lot in life in ways that are scientifically verifiable and statistically significant. Their world appears to be a place apart, a universe where women who cheat, and especially mothers who cheat, come out on top.
A cattle-rich Himba man can have several wives—and often does. Young men typically get married for the first time at the age of nineteen or twenty. But they don’t always choose their own brides. Arranged unions are common—young girls may be “married off” to strengthen a strategic alliance between families, pay back a favor, or otherwise serve the interests of a girl’s mother and father. (These marriages are not consummated until a girl is older, and she may grow up and divorce her first husband in such a case, Scelza explained to me.) A man can have several wives simultaneously, but a girl or woman has one husband at a time. In this way, polygyny seems asymmetrically disadvantageous for girls and women, apparently limiting their options in a way that it does not for men.
But it turns out things are more complicated than they appear. Brooke Scelza discovered that, somewhat like Alicia Walker’s interviewees, Himba women and girls have a “workaround” strategy. Dr. Scelza, a petite brunette and a mother who had two toddlers at the time I interviewed her, has observant, deep-set blue-green eyes and a calm, thoughtful demeanor. She began her career studying maternal and child health in Australia, and first came to the Himba’s Namibia in 2009 in search of a natural fertility population—that is, one without birth control. She initially set out to analyze how Himba mothers and their adolescent daughters interact as the girls enter their reproductive years. True to her background in evolutionary biology, Scelza has described arranged marriages among the Himba as “a form of parent-offspring conflict that daughters often lose.” Love matches, on the other hand, “reflect the young woman’s own choices, with her preferences coinciding with or superseding those of her parents.” Over lunch at the noisy, bustling UCLA faculty cafeteria where she had agreed to meet me, Scelza became animated as she explained that the crux of her work is an exploration of precisely how these different types of matches among the Himba—those made by parents with agendas versus those made by the lovers themselves—play out over each woman’s life history, and over her children’s. But she’s interested in this issue in the broadest sense as well. What does it matter, Scelza wants to know, whether women choose or live out the choices of others? And when they are forced to do something they don’t want to do, coerced into a situation that circumvents their options, what are their options then? To put it in the parlance of anthropology, what counterstrategies are available to these young Himba women in the face of constraints? Finally, Scelza wants to know not only how Himba women make the best of a situation not of their making but what their practices might reveal about our collective evolutionary past, present, and future, as well as the role that environment and ecology play in women’s sexual and reproductive choices.
To understand the Himba, what their cheating ways mean, and the important implications for the rest of us, we need to take a long and somewhat complicated detour down the road of a scientific conundrum called “female choice.” It is a path strewn with assumptions, agendas, biases, fruit flies, murderous male langurs, vibrators the size of dining-room tables, babies with more than one father…and hope.
The notion of “female choice” looms large in Brooke Scelza’s work, aligning her with a number of other scientists—many of them women—who have over the last decades challenged their field’s fundamental beliefs about female and male reproductive strategies, as well as its emphasis on supposedly universal sex differences. “Female choice” in matters of sex and reproduction has, until relatively recently, been overwhelmingly portrayed as a passive affair. This characterization began with The Descent of Man, and Selection in Relation to Sex (1871), wherein Charles Darwin outlined his great, important, and original theory of sexual selection, a type of natural selection that arises when individuals of one sex prefer certain characteristics in the opposite sex. He believed that females of most species, including humans, essentially “auditioned” males, passively (in relative terms to male competition) turning some down in search of the one with the biggest horns or the most symmetrical features or the highest status, presumably because he had the best to offer: sperm quality, resources, protection. Darwin introduced this idea of selecting by auditioning, which was later dubbed “intersexual choice.” He believed that males, on the other hand, actively fought one another to be noticed, to put their best qualities on display and to “win,” either by being chosen or by excluding their male rivals so a female would have no choice but to mate with them. Cue two male bighorn sheep dramatically crashing their heads together, the startling noise of the impact echoing through the mountains. Now imagine a peacock displaying his extravagantly beautiful iridescent feather train. Darwin also noted the phenomenon of masculine striving and struggling and display, all this peacocking pageantry that is today called “intra-sexual competition.” That is, competing with your own sex because you want to vanquish your rival either physically or by getting the other sex to notice you and choose you over him.
Because males were performing, displaying, and being chosen, the thinking went, it was males who were acted on by sexual selection, their traits passed along, or not, motored by female (comparatively) passive choice. It was just a heartbeat from this view that “active” males fought or competed or assertively displayed for “passive” females to the idea that females were not only discerning but also naturally coy, demure, and reticent in their mating strategy compared to males:
The female…with the rarest exception…is less eager than the male…she generally requires to be courted; she is coy, and may often be seen endeavoring for a long time to escape from the male…Man is more courageous, pugnacious, and energetic…Woman seems to differ from man in mental disposition, chiefly in her greater tenderness and less selfishness.
As primatologist Sarah Hrdy observed, “To Darwin, elusiveness was as integral to female sexual identity as ardor was to that of their male pursuers.” And the stakes of this distinction between male and female, ardent and elusive, active and passive, coy and eager, selfish and tender, were high. Indeed, all of civilization, Darwin and his contemporaries suggested, hung in the balance. The English gynecologist William Acton, author of the ambitious and influential The Functions and Disorders of the Reproductive Organs in Childhood, Youth, Adult Age, and Advanced Life, Considered in the Physiological, Social, and Moral Relations (1857), may have influenced Darwin’s thinking and was another voice contributing to the culture’s discourse about “inherent” female sexual restraint and even aversion to sex. Women with sex drives, asserted this well-respected thought leader of his time (who also believed that masturbation depleted life energies and contributed to illness), were exceptional:
…the majority of women (happily for them) are not very much troubled with sexual feeling of any kind. What men are habitually, women are only exceptionally…There are many females who never feel any sexual excitement whatever. Others, again, immediately after each period do become, to a limited degree, capable of experiencing it; but this capacity is often temporary, and will cease entirely till the next menstrual period. The best mothers, wives, and managers of households know little or nothing of sexual indulgences. Love of home, children, and domestic duties are the only passions they feel.
In Acton’s characterization, women are at once chaste, lauded, and sentimentalized supra-sexual beings; and creatures driven by biology (their menstrual periods). But in no instance do they exercise agency in matters of their sexuality, which, after all, they do not “have,” their “passion” having been rerouted into “love” of the domestic sphere. In many ways, Darwin’s view of sexual selection and Acton’s take on female sexuality culminated in Krafft-Ebing’s apocalyptic vision of what would happen if we undid such an order of things, which he offered up in 1886: “If a woman is normally developed mentally, and well-bred, her sexual desire is small. If this were not so, the whole world would become a brothel and marriage and family impossible.”
Female passivity and sexlessness is the homeostasis that keeps the world in balance.
And yet. During this very era, husbands were literally paying other men to serve their wives sexually. In her book The Technology of Orgasm, Dr. Rachel Maines tells us that from the 1850s to the early twentieth century, women with various nervous disorders and complaints visited doctors who palpated and massaged them below the waist in order to cure their “nervous conditions” with a “release of nervous energy”—an orgasm. After this physician-administered “hysterical paroxysm,” which doctors considered “a medical duty like breaking a fever,” in Maines’s words, many women found themselves temporarily cured of exhaustion, melancholy, and nervousness. The process could take up to an hour, however, and left doctors longing for a quicker, less labor-intensive way to do it for their female patients. The vibrator was born of male (medical) frustration in the face of (muted) female sexual demand, giving birth to large, steam-engine-powered contraptions like The Manipulator, invented by US physician George Taylor in 1869. It was the size of a dining-room table and had a small, vibrating sphere attached to a cut-out section. It wasn’t just big—it was also a lot of work. “Doctors didn’t like shoveling coal into it,” Dr. Maines gamely told a reporter in 2012. Cumbersome as they were, such outsized orgasm machines cut the time to “paroxysm achievement” from an hour to five minutes. In addition to their efficiency and efficacy, these proto-vibrators reassured everyone that Krafft-Ebing’s vision of cultural collapse had been averted, preserving and reasserting as they did the notion that female sexuality was as passive as a pallid, unconscious neurasthenic lying motionless on her gurney.
Woe to the woman like the twenty-four-year-old middle-class Boston wife who threatened to destabilize that belief and the entire social order by speaking, even privately to her physician, about wanting and needing sex. In 1856, an unfortunately honest patient the gynecologist Dr. Horatio R. Storer called “Mrs. B.” told him of her vivid dreams of sexual intercourse with men other than her husband. These adulterous visions tormented her in her sleep. And even in her day-to-day life, she confessed, speaking to a man might trip off nearly overwhelming sexual feelings, fantasies, and urges about him. Mrs. B. further confided in the doctor that, while she had remained true to her husband, she feared she might not be able to hold off temptation forever. She attributed her problems to being childless, and also to her husband’s trouble maintaining an erection and so his inability to have intercourse with her daily, as had until recently been their habit. In her book Nymphomania, Carol Groneman notes that given the prevailing beliefs about women being asexual, Mrs. B. must have been extremely worried about her adulterous thoughts and what we would today call her libido in order to override the fear of censure and discuss them at all. After a physical exam, Dr. Storer reported that “her clitoris was normal-sized, her vagina slightly overheated, and her uterus somewhat enlarged.” He also reported that Mrs. B. complained her clitoris always itched. When Storer touched it, he wrote, she shrieked with excitement. The shaken doctor told her that if she did not immediately undergo treatment, she would probably need to be committed to an asylum. His prescription: that she abstain from intercourse with her husband, who moved out of their home temporarily, and that her sister move in to supervise her course of treatment. Mrs. B. was forbidden to eat meat or drink brandy and directed to avoid any stimulants that “might excite her animal desire.”
The patient was ordered to replace her feather mattress and pillows with ones made of hair to limit the sensual quality of her sleep. To cool her passions, she was to take a cold sponge bath morning and night, a cold enema once a day, swab her vagina with a borax solution…[and] give up working on the novel she was writing.
Agency was the issue. While it was fine to require that an orgasm be administered while one lay prone, splayed, and immobile on an examination table, a married woman needing or desiring one from a lover or even her own husband was pathological. Thus merely speaking about it would bring down a vast array of sadistic containments masquerading as cures—everything from chemical torment of one’s vagina to the quashing of artistic ambition.
Such hysterical reactions to the expression of female sexual desire worked to contain and constrain Mrs. B. And other women too. The paradigm that females are sexless and decorous protectors of the hearth prevailed for decades, even in the face of intervening generations of abolitionists, suffragettes, and crusaders from Ida Wells to Margaret Sanger critiquing it with their pointed activism. And while flappers—originally a derogatory English term for prostitute—made real strides by boisterously presuming the liberties and freedoms that suffragists and others attempted to engineer through lobbying, legislation, and political protest, with the onset of the Great Depression in 1929, historians of the era tell us, these pioneering young disruptors were bludgeoned back into propriety. In fact, even working outside the home was suspect for the next decade, and women who tried might well be subjected to public censure, “taking jobs from men.” Making matters still more difficult for women of color, between 1932 and 1933, 68 percent of jobs posted by the Philadelphia Employment Bureau stipulated the jobs were “white only,” doubling down on the discrimination.
Women arguably didn’t have an opportunity to challenge rigid gender scripting that placed them in the domestic sphere and men in the world of action and agency, reasserting an overarching vision of female passivity consistent with Darwin’s, Acton’s, and Krafft-Ebing’s, until men were off to Europe and the South Pacific for World War II in the early 1940s. Then, with holes in the industrial labor force, American women took jobs in factories and shipyards; others ran offices and their households. It was a world without men, a world of burgeoning female competence and confidence, even in traditionally male arenas like heavy manufacturing. Women wore jeans and made bombs in factories, with Rosie the Riveter exhorting them all along, “We Can Do It!” Female agency, aptitude, and autonomy were not merely tolerated; they were encouraged, nurtured, and publicly extolled as patriotic. Between 1940 and 1944, female labor force participation grew by nearly half. And with most men away, women weren’t just working in factories, rising to the top in their office jobs, and generally running the show. Historians, cultural critics who study gender, and sex researchers have noted that “situational lesbianism” is common in contexts—from Saudi Arabia to all-girls schools to women’s prisons to wartime—where there is a dearth of men. And with social scrutiny relaxed and men out of the picture, lesbians had unusual freedoms, notes historian Jessica Toops, while avowedly heterosexual women were more likely and able to pursue romantic and sexual relationships with other women, acting on what sex researcher Lisa Diamond calls “female sexual fluidity.”
But such freedoms were contingent and relatively short-lived. The notion that females were naturally and should be sexually reticent, domestic, heterosexual, and a whole lot more got another shot in the arm in 1948. That year, an English botanist and geneticist named Angus Bateman, who had previously focused on the genetic properties of barley and rye and cross-pollination in seed crops, published a paper in the Journal of Heredity about Drosophila melanogaster, or fruit flies, and their mating strategies. What these flies allegedly did, and what it all supposedly proved, would have surprisingly vast implications for human women.
Bateman assembled and observed groups of equal numbers of male and female Drosophila melanogaster, held in bottles. They mated freely. Later, Bateman classified the offspring by genotype.
Bateman had undertaken this experiment because he was keen to emphasize that while Darwin had a theory of sexual selection based on observation, he had no proof. Bateman quickly made two claims based on his own study results. First, he asserted that males’ reproductive success was more “variable” than females’ reproductive success. That is, nearly 96 percent of the females reproduced, while only 79 percent of the males managed to. Bateman also observed that “male fertility increased in a linear manner as a function of the number of copulations achieved, whereas the fertility of females showed little increase as a function of the number of copulations beyond the first.” That is to say, males benefited from copulating again and again, according to Bateman; for females, it made little difference.
Why should it be the case that males benefited from multiple mating, while females didn’t? Why was what was good for the gander not good for the goose? Bateman and those who later embraced his findings believed that a female’s reproductive success was limited by biology—the number of eggs she could produce—while for the male “fertility is seldom likely to be limited by sperm production, but rather by the number of inseminations or the number of females available to him.” Like Darwin, Bateman was sure sexual selection acted more directly on males than on females, because of differences between the sexes when it came to the cost of producing gametes. Eggs were labor-intensive, relatively precious treasures; sperm, in contrast, were presumably much cheaper. There were so many of them! This incontrovertible biological difference not only drove but determined both sexual and social behavior:
There is nearly always a combination of an undiscriminating eagerness in the males and discriminating passivity in the females. Even in a derived monogamous species (e.g. man) this sex difference might be expected to persist as a rule.
Bateman’s paper and its assertions dropped at a moment—1948—when troops had returned home and were readjusting to a social world that had been radically reordered. How would men be reintegrated into a universe in which they had been, for a time, not only absent but irrelevant?
For starters, men needed their jobs in manufacturing and industry back. And so women would have to give them up. Society mobilized to get them to do just that—through shame, guilt, and a propaganda program about the social importance of stay-at-home wives and mothers. As historians have pointed out, the rise of 1950s suburban living in the US, with its dearly held belief that a woman’s place was in the home and that to be female was to be fulfilled by the calling of intensive care for one’s children, household, and mate was certainly aided and abetted by the GI Bill, television shows like Leave It to Beaver and The Adventures of Ozzie and Harriet, and even fashion (Christian Dior’s lavish, wasp-waisted, and stilettoed “New Look” made it aggressively clear that it wasn’t chic to dress for a factory line anymore). One government PSA from the period showed a female factory worker in court, imploring the judge for a light sentence for her son accused of vandalism. “The message to women was clear,” writes historian Melissa E. Murray. “There was no need to [stay] in the labor force. Instead, women were needed back at the hearth in their traditional role as mothers responsible for the careful rearing of productive citizens.”
Good mothers didn’t work. They went to court to bail their kids out. They cooked and cleaned. Their work was the home. Bateman’s conclusions participated in cajoling women out of the workforce in an admittedly indirect but hardly subtle way. Insights about Drosophila melanogaster helped reassert plough-informed gender roles by giving scientific credence to the idea that females are by nature sexually exclusive nesters who find satisfaction not in the world of action, competition, and earning but in monogamous heterosexual mating and intensive investment in their offspring.
Die, Rosie the Riveter.
Bateman’s paper wasn’t just efficacious in the short term, useful in the overarching social effort to guide women from the factories to the kitchen and reestablish the hierarchy between men and women that had been upset by the war’s reorganization of who did what. Over the next decades, it became an urtext of sorts, indisputable evidence that sexual selection acts differentially on males than on females and that only males—reaffirmed to be “pugnacious, courageous, and assertive,” just as Darwin had described them—benefit from multiple mating. “Intra-sexual Competition in Drosophila” has been cited directly more than three thousand times since its publication, according to Google Scholar; historian Donald Dewsbury notes it “became standard fare in textbooks” and lectures in the fields of biology, genetics, and anthropology. Just as important, Bateman’s findings have been presumed universally relevant and generalized to females of other species, including, as Bateman suggested, to humans. In the 1970s, the dashing and controversial Harvard sociobiologist Robert Trivers popularized Bateman all over again, bringing his views to an even wider audience. Trivers refined Bateman’s point by suggesting that a female invests more in offspring both before and after it is born, because fertilization and gestation—often of only one offspring at a time—take place in her body. And because if she is a mammal, she lactates. As a consequence, he argued in his theory of Parental Investment, her maximum reproductive output is limited compared to a male’s. Males, on the other hand, could reproduce pretty much limitlessly, if they were sufficiently caddish. Which, it seemed, was in their best interest.
In this view of the “natural order of things,” a female’s one-shot monthly fecundity, energetically costly and risky gestation, and her consequent strategy of comprehensive investment in her young put her fundamentally at odds with males. She wanted quality, not quantity—one great guy with great genes and one or two young at a time to take care of intensively. But males, those comparatively footloose and fancy-free XY scoundrels with their boatloads of quick, inexpensive sperm, would naturally want to spread themselves around, siring as many offspring with as many females as possible. They wanted quantity, not quality in the mating and fathering game. The bottom line, yet again, was that monogamous social behavior and all the qualities presumed to go with it—being demure, choosy, reticent, and retiring—was essentially female behavior. Males, this line of thinking went, were naturally “eager.”
Primatologist Sarah Hrdy points out that what has been called “the Bateman paradigm”—the linked notions that males have greater variation of reproductive success than females do; males gain from multiple matings and females do not; males are generally ardent and females retiring; and the implicit presumption that females are more logically and naturally monogamous than males—has influenced entire generations of thinkers. After Trivers put forth his gloss on Bateman, everyone from evolutionary psychologists to biologists to writers for GQ and Maxim, who produced pat article after pat article asserting that “men stray while women stay because of genes,” perpetuated it.
If Bateman’s conclusions about sex roles and sexual selection, and science and popular culture’s embrace of it, read like a suspiciously wistful and retroactive justification narrative in which males are active doers, competing and winning and losing and striving and eager to spread their seed and then bolt, as passive, coy, choosy females rain on their collective parade and try to get them to be true while expecting never to pay for their own drinks, that’s because it is. As real gains in equality put women in charge of their reproduction, their earnings, and their destinies more generally in the last decades of the twentieth century, Bateman’s ideas would be periodically reactivated like a virus by anxiety about social change. Wherever and whenever women were independent and in little need of being protected and provided for, the notion that they should passively choose the one most powerful male to safeguard and provision them, and all that it implied about femaleness versus maleness, would be aggressively promulgated by a range of scientists, writers, and politicians whose interests it served. A simplified and essentialist version of sociobiology revved its engine and got remarkable traction throughout the 1970s (a 1977 cover of Time showed a man and woman hanging from marionette strings, arms intertwined, with the headline “Why You Do What You Do: Sociobiology”) in part because, as had been the case in the Drosophila paper after World War II, it was a response to a home-front social and sexual revolution, including the dismantling of a rigid gender script and rejiggering of traditional gender roles. Thirty years later, as women in the US continued to make strides in the workplace, closing the pay gap and grappling with “having it all,” Bateman’s notion of universal, timeless biologically based differences of sexual strategy found expression in a bestselling memoir:
In primitive times women clung to the strongest males for protection. They did not take any chances with a nobody, low-status male who did not have the means to house them, protect them, and feed them and their offspring. High-status males displayed their prowess through their kick-ass attitudes. They were not afraid to think for themselves and make their own decisions. They did not give a crap about what other people in the tribe thought. That kind of attitude was and still is associated with the kind of men women find attractive. It may not be politically correct to say, but who cares. It is common sense and it is true and always will be.
The anthropologist Holly Dunsworth has written about all the ways Trump got evolution wrong here, from his misapprehension that it was competition rather than cooperation that helped us thrive to his fantasy that human females are “naturally” power-fixated gold diggers. This highly selective version of sexual selection’s role in evolution is one that plays in Trump’s America, and the version of masculinity it suggests—muscular, fearless, and dominant—arguably helped Trump win the election. It did not hurt that his opponent was an “unnaturally” ambitious woman who didn’t know her place (or essence, apparently) and whom Trump suggested he might “lock up.” (“Lock her up is right!” he enthused as supporters in Pennsylvania chanted the phrase.) Like Dr. Storer’s patient Mrs. B. in 1856, women who slipped out of the bounds of the Trumpian Eden, where passive females seek the protection and sperm of active and assertive males, were a threat to be contained and then annihilated. Instead of recommending a borax vaginal wash, the man who is now our president used and continues to use verbal coercive tactics, including, famously—in a phrase that reasserted that essential differences were essential destiny while it echoed William Acton’s preoccupation with menstruation—describing a woman who stepped over the line as having “blood coming out of her wherever.”
But as for Bateman’s science—popular, popularized, politicized, and sometimes populist—it wasn’t merely biased by and influential upon its cultural moment. Over the intervening years a number of scientists, many of them women, began to suggest it was also highly questionable in light of how females of many species—including non-human female primates and women—actually behave. The presumptions built upon Bateman’s findings (“Men have sports cars to get lots of women,” “Women just naturally want to stay home with the kids and one man—that’s how it was in caveman times,” “All females need and want an alpha,” “Males naturally want sex more than females do,” and so on) began to fall like so many houses arrogantly, haphazardly erected on quicksand.
Primatologist Sarah Blaffer Hrdy was one of the first scientists to challenge Bateman’s conclusions, though she told me she had no inkling that’s where her work would lead at the time. “I just wanted to study langurs,” she told me with a laugh as we sat in the living room of her home in Northern California and I asked her about being David to the Goliath that was her field’s faith in the received notion of sexual selection, female choice, and “coy, choosy” females contrasted with “ardent” males. Hrdy’s adventure started, as those of so many female primates do, with sex. For work on her doctoral dissertation while she was a graduate student at Harvard, Hrdy traveled to Mount Abu in Rajasthan, India, to observe Hanuman langurs (Semnopithecus entellus) there. She noted that the females sometimes left their troops to copulate with outside males, seeking them out for sex even when a more familiar male was in residence. Why would that be? And how could it be if, as Bateman asserted and everyone knew, “sexually adventurous females were not supposed to exist,” in Hrdy’s words? Hrdy had been inspired, even compelled, to trek to Mount Abu by what would turn out to be a life-altering undergraduate lecture in a course taught by Harvard anthropologist Irven DeVore. He mentioned that in a species of monkey she had never heard of before, Hanuman langurs, males sometimes attacked and killed infants. At the time, it was thought that this bizarre male behavior was due to overcrowding. At Abu, Hrdy did indeed witness males attacking infants but realized the attacks were almost always by males who had recently entered the troop from outside it. Stalking a female with an infant sometimes for days, these invading males acted with sharklike intent. When an opportunity presented itself, the male would attempt to seize the infant from its mother and sink his daggerlike canines into its skull or other body part. While females sometimes fought back, even forming coalitions with other females to fend off the attackers, the males usually won. Disconcertingly to us humans, and perhaps especially to us human mothers, the mothers of the dead infants would then mate with the killers of their offspring. Resident males, on the other hand, were extraordinarily tolerant of infants and never attacked them, suggesting that by itself population density was not the issue. What was going on?
For Hrdy, an idea soon began to take form. An infanticidal male “eliminated the offspring of the last choice a female had made,” thereby causing the mother (who was no longer lactating) to resume cycling and to ovulate sooner than she would have had her infant survived, drastically “distorting her options.” In order not to be outbred by competing females, she needed to mate with the male now available, the male who would presumably keep another potentially infanticidal invader at bay, even if that male was her baby’s killer. “All this made sense in light of Darwin’s ideas about sexual selection, that is, males competing with other males for access to matings with the outcome for the loser of not death, but few or no offspring,” as Hrdy told me in an email recalling her fieldwork in Abu. But what about the females? What was motivating them? How might their behavior be adaptive? Once a male had killed her offspring and she cycled again, particularly if the murderous male was guarding her closely from other males, it was in a female’s best interest to mate with him. But she wouldn’t stop there. Once she realized that males were only attacking offspring born to females with whom they had never mated, offspring they could not possibly have sired, Hrdy hypothesized that females might seek to manipulate information available to males about paternity by preemptively mating with potential invaders. Confounding prevailing wisdom that female primates only mate at midcycle, when they are in estrus, Hrdy also realized that these females would solicit copulations from males at times other than midcycle, even when they were already pregnant. She wondered if such situation-dependent estrus behavior could be a preemptive female strategy to counter male infanticidal coercion. Might copulating with multiple males allow the female to “game” paternal certainty and plant a seed of confusion, so to speak? After all, by mating multiply, a female langur was engineering the possibility that these lethal males, potential killers of her infant, had actually sired it. And this, Hrdy realized, would make it less likely that a male would kill the infant that might be his. The only way to fool the males was to mate polyandrously, sometimes even in rapid sequence with numerous partners. Not only was this not “unnatural,” it was beneficial, Hrdy asserted, suggesting that female langurs bred multiply as a form of insurance.
Later, Hrdy hypothesized that such mating behavior, which she reframed as “assiduously maternal”—behavior likely to keep her baby alive—and now widely reported for many species of primates, could under other circumstances actually increase the odds that males, even more than one “possible father,” would protect, care for, and even provision her infant. All in all, given the right ecological and social circumstances, mating with multiple males might be very beneficial to females indeed.
Logical, reasoned, and grounded in solid science as her ideas were, Hrdy set off shockwaves with her suggestion that infanticide might be an adaptive reproductive strategy for males and, stranger still, that it might be adaptive for females to engage in multiple matings so as to confuse paternity. “Those monkeys are deranged,” she recalls a prominent physical anthropologist saying dismissively of her work and her 1977 book on the topic, The Langurs of Abu. It was easier for that anthropologist, and anthropology in general, to pathologize an entire troop of langurs and dismiss Hrdy’s many months of meticulous fieldwork than it was to concede that males might operate selfishly rather than for the “good of the species.” Perhaps even more shockingly, Hrdy’s insights challenged the Darwin-Bateman paradigm, which was so foundational to the thinking not only of scientists but of Americans, who were deeply invested in the generations-old belief that sexually passive, “coy” females who once mated with the “best” available male would have no incentive to stray.
In her 1981 book, The Woman That Never Evolved, Hrdy took aim even more directly at the passive, coy, monogamous female hypothesis, suggesting that observational data demonstrated it simply wasn’t the case in many primates, including humans, and that Darwin’s notion that retiring, disinterested, exclusivity-craving females drove sexual selection by seeking the one “best” male was more based in wishful thinking and social convention than in actual primate behavior. Moreover, she made the case that female primates, particularly mothers, were not exclusively tender, monogamous, and passive. Females might also be sexually assertive, selfish, shrewd, and, under some circumstances, not even necessarily nurturing.
In her later book Mother Nature, she would show that among primates where mothers need a lot of help from others in order to rear their young (as is the case in humans), the same mother who lavished her infant with attention under favorable ecological circumstances might, when short on social support, refuse to nurse it or even abandon an infant at birth. Rather than being unnatural, such a mother was balancing her own well-being against that of her current offspring and also potential offspring she might bear in the future. Such a mother might be devoted and doting—or indifferent. She might nurse diligently, long past the time when her conspecifics had given it up, or tirelessly allow her infant to ride ventrally, clinging to the fur rather than locomote on its own. And then that same indulgent and fastidious mother might set her infant down, casting it momentarily, or more permanently, aside. As with female mating behaviors, maternal behaviors were far more variable, flexible, and strategic than previously assumed.
Hrdy’s assertion that female primates were sexually strategic and acted with agency left her open to criticism. One colleague writing in the Quarterly Review of Biology equated her hypothesis that female primates benefited from mating with multiple males with “parapsychology.” Others made it more personal, accusing her of projecting. “So, Sarah, put another way, you’re saying you’re horny, right?” one colleague inquired. (Hrdy called this “one of the more mortifying moments of my life.”) But her work also opened the floodgates for more research that challenged the status quo.
It was soon observed and eventually widely accepted that males of many mammal species committed infanticide to force females into estrus, and that females bred not passively but strategically, and often, and frequently with multiple males. From female macaques in captivity who craved sexual variety so much that they grew listless and depressed if keepers didn’t cycle in new males every three years; to ostensibly “monogamous” female gibbons who copulated with other males when their partners were out of sight; to female chimps who risked their lives attempting to join new troops in order to copulate with novel males—there was good reason, primatologists including Meredith Small, Alison Jolly, Barbara Smuts, and Jeanne Altmann argued, to reexamine with a critical eye the presumed “universal” sex differences in sexual and reproductive strategy based on Bateman’s principle. Females had a lot more agency than previously supposed. Under a variety of circumstances they did mate multiply and they did benefit from it.
How, exactly? Not only could “promiscuous” females decrease the likelihood of infanticide. They also could increase their chances of conceiving by upping their likelihood of getting high-quality sperm. They could hedge against male infertility. Multiply mating females improved their odds of heterozygosity—a good match between their egg and the sperm that fertilized it, resulting in a healthier baby. But there was more to it. It turned out there were non-procreative benefits of multiple mating for females as well. By copulating with a slew of males when she wasn’t in estrus or fertile—basically by having sex recreationally—a female primate could deplete the sperm available to rival females. She could recruit males to her social group, thus having more potential caregivers and protectors and provisioners. She could trade sex for resources or “friendship.” Of course Hrdy’s female langurs didn’t have some conscious endgame. They didn’t mate multiply because they figured, “Hmmmm, better confuse the issue of paternity and line up multiple possible ‘dads’ to protect my baby” instead of attack it. Nor did other primate females think, “Boy, would I ever like to increase my odds of heterozygosity” or “get some really good genes,” or—in species where male support is essential—get several males to care for or provision her offspring, thinking, “I need to line up several providers.” Females solicited males because they were conditioned to additional matings that might feel good. And it felt good because of the way ancestral female primates were built. This was the “legacy” we human primates inherited from ancient ancestresses living under quite different conditions than women do today.
Sure, we have been portrayed not infrequently over the last centuries by science, medicine, and art as the passive, comparatively disinterested sex. But biology suggests a vastly different backstory, a tale of passionate, voluptuous pleasures and sometimes of tremendous risk-taking in the pursuit of sexual satisfaction. Our bodies are designed for sin; they are hedonists even when we’re not.
Women, along with female chimps, bonobos, and a number of other non-human primate species, evolved a forward-facing, richly innervated clitoris. Previously thought to be a mere button, now known to be a superhighway of decadent sensation-for-the-sake-of-it, including three- to four-inch-long paired legs, the human clitoris is truly, as suggests the ancient Greek word that denotes it, “the key” when it comes to understanding the anatomical and biological underpinnings of female sexuality. It is vast, the same size as a penis, but on the inside. Yet even just the part of the clit we can see, the glans—think of it as the tip of the iceberg, or perhaps better, the mouth of a simmering volcano—has more than eight thousand nerve endings, meaning it has fourteen times the density of nerve receptor cells as the most sensitive part of a man’s penis, also called the glans. That makes the clitoris epically more responsive and excitable than the tip of the penis.
Terminology like “glans” aside, men—whose junk develops from the very same embryonic tissue women’s does—are very different in one respect. Their penises are functional, for urinating as well as ejaculating, multitaskers for biology, sensation, and reproduction. Meanwhile, the little bud that stands at attention, the clit we thought we knew, is merely the ticket to the roller-coaster ride and serves no greater or lesser purpose than to make us feel good. The entirety of what is now known as the “female erectile network” (FEN) or “internal clitoris” snakes back nearly to our anus on either side; extends along our labia, which swell with pleasure; and includes our urethral sponge (previously called the G-spot) and something called the perineal sponge too.
And women, unlike men, can have orgasm after orgasm. “Women don’t require a refractory period like men do, so we’re able to stay aroused longer and have [subsequent orgasms] with little effort,” says Rachel Carlton Abrams, MD, co-author of The Multi-Orgasmic Woman. Conventional wisdom has it that men come and are done.
But female orgasm is, in actual real-life conditions—in beds and showers and the backseats of cars, in dorm rooms and conference rooms and marriages and hookups and trysts—a moody bitch. She is notoriously reticent. And like the clitoris itself, which retracts under its hood when stimulated, female orgasm can be elusive. Her rewards take some know-how, and patience. According to Manhattan psychiatrist and sex therapist Elisabeth Gordon, MD, studies tell us the average time for a woman to orgasm from intercourse after stimulating foreplay ranges from ten to twenty minutes, while for men it is two and a half to eight minutes. “The only hard and fast facts regarding time to orgasm are that there is a range, and women take longer on average, and that it’s faster from self-stimulation.” And it’s not uncommon for women to fear they are taking “too long,” Gordon observes. There is no doubt that this latter fact is at least in part a symptom of a culture-wide failure to tell women that great sex is our right, and that we are entitled to “release” as we have been taught men are. Among heterosexuals, there is a significant “orgasm gap” as well as a sexual entitlement gap: one study found that when it comes to sex with a familiar partner, heterosexual men come a hefty 22 percent more often than women do. (Bisexual women fare no better than straight women, while lesbians come out on top, experiencing orgasm nearly 75 percent of the time during partnered sex.) Another study found that in first-time hookups, straight men have over three orgasms for every orgasm a straight woman has.
The unpredictable nature of orgasm—will we or won’t we?—may drive us to constantly seek its fulfillment. We know that when it comes to playing slot machines, we become addicted not by getting what we want every time but by the happenstance nature of our win. Same with checking our iPhones. If we had the emails and texts we craved every time we looked, we would soon grow bored of and devalue the very rewards we sought. Consistent fulfillment doesn’t stoke desire the way the hope and anticipation of unpredictable fulfillment does. It is intermittent reinforcement, with its non-pattern pattern of the occasional jackpot, researchers tell us, that keeps us coming back for more.
In addition, the fact that stimulation that leads to orgasm is cumulative is something that has long intrigued primatologists, including Hrdy. We experience a sense of “buildup” as we draw nearer to climax, and it takes time, particularly from intercourse. More time than it takes a man.
This specific cluster of characteristics defining female orgasm may well have helped make the human female, under certain conditions, a restless and relentless sexual adventuress. Our ancestors, like many non-human primates today, including our closest relatives, chimps and bonobos, may well have regularly consorted with several males in rapid succession, seeking, with each partner, to build up to the eventuality of an orgasm or multiple orgasm.
The proof is in the primates. By now it’s well established that rather than being uniquely human, female orgasms occur in other primates as well, in chimpanzees and various species of macaques. Laboratory studies using implanted transmitters record physiological response to genital stimulation, including spasmodic contractions of uterine and vaginal muscles and changes in heart rates accompanied by distinctive vocalizations and facial expressions, such as “O faces,” Hrdy told me as the sky clouded over and we contemplated the lunch of chicken potpie she planned that day. I sat with her for several hours. She demonstrated an O face, which is exactly what it sounds like, an open round-mouthed facial expression like the one female macaques, chimps, bonobos, and humans make at That Magical Moment. “This suggests that female orgasm is a legacy that predates hominins, making it not just very old but a retention from what was possibly also an essential adaptation for our prehuman ancestresses,” she explained. (At this point Hrdy’s husband, Dan, entered the room to discuss when we’d eat. “We’re talking about the evolution of female orgasms!” Hrdy enthused. Dan turned and headed in the other direction, waving his hand and saying gamely over his shoulder, “I have heard a lot about that already.”)
In an essay earlier in her career Hrdy observed, “Based on both clinical observations and interviews with women, there is a disconcerting mismatch between a female capable of multiple sequential orgasms and a male partner typically capable of one copulatory bout.” And, she further suggested, since a relatively low percentage of women experience orgasm from intercourse alone, it’s hard to warrant any claims (there have been some) that the female orgasm evolved specifically in humans as an adaptation for fostering heterosexual monogamous pair bonds. Au contraire. Given all the advantages of mating multiply, it makes sense that there might be this “variable reward system” in response to sustained, even cumulative, stimulation, unpredictable and delightful, that over millions of years has kept female primates soliciting successive copulations. It can be no coincidence, Hrdy observed, that so far female orgasm among non-human primates has been best documented in non-monogamous species. As she wrote to me, forget trying to explain the evolution of female orgasms or contemporary mismatches by studying women under current conditions. Rather, we need to ask how this ancient legacy, inherited from prehuman ancestresses, has changed over human evolution and human history.
Sex at Dawn authors Christopher Ryan and Cacilda Jethá suggest that the story of a woman’s cervix makes Hrdy’s version of females conditioned to seek orgasm with multiple partners in rapid succession for deep reasons even more likely. For the human female cervix, like that of a promiscuous macaque who may breed with ten males or more in rapid succession, actually serves not so much to block sperm, as was previously believed, as to busily filter and assess it, ideally several different types of it from several different males, simultaneously. It evolved not as a simple barrier but to sort the weak and bad and incompatible sperm from the good, suggesting by its very presence that there was a need to do such a thing—i.e., that females were mating multiply. Such a wondrous bit of equipment also partially buffers the female in possession of it against making a poor mate choice in the heat of the moment—our cervix is there to help us judge who’s eligible when our eyes fail us.
Male equipment tells a similar story about the likelihood of a long history of females mating multiply. Consider the size of a human male’s testicles. They are larger than those of gorillas, whose teeny-tiny balls relative to their body size suggest that only a small amount of sperm was needed to successfully inseminate a female, who is unlikely to have other potential mates (gorillas live in social formations some primatologists still call “harems”—a male and multiple females). A man’s testicles, in contrast, are proportionally larger, arguably more like those of chimps and bonobos, whose females are notoriously promiscuous. Logically, when dealing with a female consorting with multiple males, you need a lot of sperm to compete with other sperm inside the vaginal canal. The more you can squirt, the better. As to sperm itself, it also tells a tale. Sperm plugs—just what they sound like: a mixture of ejaculate, mucous, and coagulating protein that gums up a female’s vagina in an attempt to keep one’s own sperm in and block a rival’s from getting up there—are a thing among chimps and bonobos, with whom we share an estimated 98.7 percent of our genetic material, and numerous other primate species. When dealing with rival sperm, you don’t just want to get yours in. If you weren’t first to the party, you want to get the other guy’s out. And the coronal ridge—the thing at the tip that makes the penis look like a shovel—is a remarkably effective remover of ejaculate. In one experiment, scientists found that a dildo with a coronal ridge removed nearly three times more of an ejaculate-like substance (made from a mixture of cornstarch and water) from a dummy vagina than ones without. And the final spurts of human male ejaculate contain a spermicide-like ingredient. “Take that!” it asserts to any rival who comes along in the subsequent hours (or minutes).
Still other researchers see our very cries of pleasure as proof that when it comes to being untrue, females were ever thus. Primatologist Zanna Clay actually studied chimp vocalizations during sex and learned it is a way females effectively signal to males, “Here I am, and I’m interested in you, other guys!” even during the act of copulation itself. Moaning and groaning may be an ancient script of sorts, by which we communicate to any other males in hearing range, “Receptive and ready just as soon as this is over!”
We are not chimps or langurs, of course. But Hrdy and the numerous scientists and thinkers she has influenced ask, Why would human females be designed as we are (and why would males have the penis shaped the way it is, and ejaculate with spermicide, and testicles the size they are) if women hadn’t been able to seek out the rewards our bodies promised, presumably serially and without much trepidation or undue fear of serious reprisals or consequences? And if seeking sex with multiple partners had always been restricted and at times even as lethal as it is today, how could we be here, designed as we are now? To consider the clitoris and the nature of female orgasm and the cervix too, as well as male equipment and the way we have sex, is to confront not just the vague possibility but the likelihood that women are made for sexual gratification and for pursuing it, and for mating multiply, in ways that men—who come and are done—are not. Female biology suggests that women are built for sexual experimentation, for reckless days and heedless nights, putting us in conflict with our current cultural container, to put it mildly.
There is no one way of having sex we “evolved” for—we are flexible sexual and social strategists. But our essence, if we can be said to have one, is likely less matron and more macaque. Female infidelity is a behavior with one foot in the present day and the other in our ancient past, linked to anatomy, physiology, and reward seeking. And the best mother is the one who, when circumstances are right, does what it takes to line up allies who will be well disposed toward her offspring. She might do so on her back, or with her rump in the air.
In the field of primatology, from Hrdy’s game-changing multiple-mating and infanticide hypothesis and insights about the nature of female orgasm to Barbara Smuts’s unexpected observations about female olive baboons who choose mates from among numerous male “friends” to Meredith Small’s assertion that the single most observable characteristic among female non-human primates is a preference for sexual novelty, presumptions that female monogamy is timeless and essential have taken a beating.
—why, she would hang on him,
As if increase of appetite had grown
By what it fed on; and yet, within a month—
Let me not think on’t—Frailty, thy name is woman!
—Hamlet, act 1, scene 2
Over the last several decades, as primatologists challenged the accuracy of the assertion that monogamy is our legacy, as well as the assumption that it was driven by females because of their biology, their insights pressured a shift of perspective about how, where, and why human females practice multiple mating. For example, on the Mosuo practice of sese, or “walking marriage,” in southwestern China, wherein women live with their kin and sexual partners slip into their rooms at night. Mosuo men do not support their offspring financially or socially (it’s a woman’s brother who “fathers,” so that Mosuo uncles are “dads”). And women are permitted to have multiple marriages. Rather than focus solely on how this arrangement benefited men, anthropologists began to see the benefits to women of raising their children in the context of an extended family without input or potential conflict from unrelated men. There are polyandrous arrangements in rural Tibet, where a woman may be married to several male siblings, a strategy that is thought to make it more efficient to farm the challenging mountainous terrain in order to provision kids and adults alike, and to prevent skirmishes over land inheritance. But it also benefits women, in an unstinting climate, to have several related “father figures” invested in her child’s (and by extension her own) well-being. And there are many more societies with “non-classical polyandry” in which women have multiple partners simultaneously or over time, with very little or no social censure. Ethnographic evidence of such informal polyandry has been reported in a total of 53 societies (and primatologist and anthropologist Meredith Small, in a survey of 133 societies, said there was not a single one without female infidelity). By 2000, Sarah Hrdy asked, “Why is polyandry so rare in humans?” and immediately amended her question by posing another: “Or is it?” Hrdy observed that “informal polyandry”—women having multiple partners at the same time or in succession—is a reality, period.
The notion that there were universal differences of sexual and reproductive strategy based on the essential, inflexible biological fact of gamete production was being battered as Hrdy and other anthropologists documented that female polygamy or “promiscuity” was a flexible behavior, an adaptation to circumstances. Women were markedly more likely to partner up with more than one man under certain conditions:
In her work among the Pimbwe of Tanzania, where divorce is a matter of one partner moving physically out of the house, with no additional legal or formal proceedings, UC Davis human behavioral ecologist Monique Borgerhoff Mulder discovered yet another reality that challenged the Bateman paradigm. Through interviews and recording of reproductive histories, she documented that, directly contradicting Bateman’s oft-cited assertions, multiple mating increased the reproductive success of Pimbwe women (meaning it increased the number of their children who survived to go on themselves to reproduce), but not of Pimbwe men. Borgerhoff Mulder further concluded that “polyandry is everywhere…but we think of it as polygyny.” That is, when we view the world and female sexuality, social behavior, and reproduction through the lens of the Darwin-Bateman paradigm, we miss the very facts that challenge this view of demure females acquiescing to sexually assertive males, who supposedly benefit from multiple mating as women do not.
Indeed, at the outer extreme of multiple mating that benefits females, anthropologists discovered and documented that many indigenous peoples of the Amazonian lowland—at least eighteen tribes, including the Canela, the Mehinaku, and the Yanomami—subscribe to a belief called “partible paternity,” which holds that a child can have more than one father. For example, when questioned by the anthropologist Kim Hill, who was attempting to learn about their kinship, 321 Aché—hunter-horticulturalists who live in eastern Paraguay—said they had a total of 632 fathers. They told Hill their different terms for their various fathers. Miare is “the father who put it in,” while peroare is “the man who mixed it.” Momboare means “the ones who spilled it out,” while bykuare means “the father who provided the child’s essence.” Opaque as these descriptors might sound to us, they point to a mind-blowing and crystal-clear belief: intercourse with more than one man is the best way to make a baby, which “accumulates” like a snowball from successive applications of semen. Women in partible paternity cultures like the Aché and the Bari have sex with several men over the course of their pregnancy, and these men in turn support her and the baby when it is born. Anthropologist Stephen Beckerman discovered that among the Bari—rainforest horticulturalists of the southwest Maracaibo Basin, which spans the border between Colombia and Venezuela—kids with more than one father are more likely to survive to adulthood, thanks to improved nutrition and protection provided by their extra dads. Eighty percent of Bari kids with secondary fathers saw their fifteenth birthdays, while only sixty-four percent of those with a single father did. In these contexts, a woman who is monogamous may well be considered prudish, selfish, and deserving of condemnation. But a woman who lines up too many fathers will find that uncertain fathers are reluctant to help. The optimal number of fathers under the environmental and ecological conditions that prevail where the peoples who believe in partible paternity live appears to be two, Hrdy tells us. A notable exception: the Canela of central Brazil, where a woman may have ritual sex with twenty or more men during community ceremonies, leaving her with many “fathers” to choose from and rely upon.
In partible paternity societies, child-rearing, unsurprisingly, often becomes a collaborative endeavor, with many adults looking out for a child’s well-being. Anthropologists call this collective raising of kids “cooperative breeding,” and many believe it is both the “how” and “why” not only of female multiple mating but also of the survival and success of Homo sapiens, when other hominins bit the dust. It was not the monogamous heterosexual pair bond that made us who we are today and ensured that we would endure, they argue, but the shared raising of offspring by multi-member groups and females who mated multiply.
On the strength of this body of data, some scientists began to rethink the idea that men had the potential to reproduce without limit. They discovered that—guess what?—sperm is not so cheap after all. Since it takes millions of sperm to fertilize a single egg, the relevant comparison is not between a precious egg and a sperm that is cheap because males produce scads of them. The relevant measure is the difference between the cost of scads of sperm and the cost of a single egg. Measured that way, sperm is more expensive than we thought. And semen, it turns out, actually contains crucial bioactive compounds that are markedly energetically costly for males to produce. Moreover, males can and do run out of sperm—a phenomenon called sperm depletion. Between the actual cost and potential scarcity of sperm, it makes sense that males may themselves in certain circumstances be quite choosy and coy about which females they have sex with. (The study of male choice is increasingly popular in biology now.)
In addition to costly sperm and sperm depletion and the reality of male choosiness, anthropologists and zoologists now question the notion of male primates fathering dozens or even hundreds of offspring just by being sexually active. This idea simply does not line up with several realities on the ground. Namely: harems are rare in the primate world, conception is statistically rare as well, and rates of miscarriage are high. How likely is it that a male hits the timing of conception just right in a single copulation? Or in multiple copulations with multiple females? Not very. And since such a significant number of pregnancies across species end in miscarriage, stillbirth, and fatal breech births, the math gets even more unfavorable for the male who ejaculates and disappears. Mating and leaving means creating the possibility that the female will mate with another male, and also that his sperm failed to do the job, or that he will not be there to try again if the pregnancy does not result in a healthy offspring. Many scientists have recently come to believe that, given all these factors, the range in male and female lifetime reproductive success actually tends to be equal. This holds true for humans and a number of non-human primates as well. Finally, as many zoologists, biologists, and anthropologists have been able to demonstrate, offspring of many species are more likely to survive if there are high levels of not just maternal but paternal care.
For all these reasons—costly sperm, the difficulty of having and guarding multiple females, the difficulty of conception, the high likelihood that a gestation may fail, the fact that dependent offspring may do better with paternal care than without—inseminating and running was never such a great strategy. The idea of naturally polygamous males and naturally monogamous females (guys who favored multiple mating over care and gals who wanted the one “right” guy) was cast increasingly in doubt in the decades after Sarah Hrdy’s insights about strategically promiscuous female langurs.
But perhaps the most fundamental blow to the belief that males benefited from multiple mating but females did not, making males “logically” more promiscuous than females, came from the laboratory of UCLA evolutionary biologist Patricia Adair Gowaty. After years of work on sexual selection, and in light of the growing body of evidence that females of many species did partake in and benefit from polyandrous or multiple mating, Gowaty put Bateman to the test in 2012, repeating his endlessly cited and vastly influential experiment, only modernized with DNA data. Gowaty discovered that Bateman’s findings could not be replicated, even in the very Drosophila he had studied. Could Bateman’s science, upon which he and a subsequent generation of thinkers had built their assumptions about female versus male nature, be wrong? At first, many experts were surprised. And surprised again—that until Gowaty, no one had ever thought to replicate Bateman’s foundational work in more than six decades. It was a classic case of confirmation bias. Scientists and social scientists had sought out behaviors that confirmed Bateman’s findings and simply didn’t see the evidence—supplied by Hrdy, Small, Smuts, Jolly, Altmann, and others—that contradicted it as anything other than exceptional. Gowaty’s lab work, combined with the burgeoning literature on populations where non-human female primates and women have sex and reproduce in ways that contradict the Bateman model, offered overwhelming proof that it was wrong to continue asserting universal difference in male and female reproductive strategies and sexual behavior based on the false dichotomy between “expensive eggs” and “cheap sperm” and between demure, monogamous females and naturally assertive, polygamous males. Males don’t have meaningfully faster reproductive rates than females. These notions were so many castles in the air.
Now what?
Brooke Scelza had been influenced by both Gowaty and Hrdy, and inspired by each of their perspectives on females as anything but passive in the evolutionary and reproductive process. And while she had originally intended to study the relationship between Himba mothers and their adolescent daughters as the young women approached their childbearing years, she wound up stumbling on a word that set her on a different path, further contributing to the comprehensive upending of assumptions about female choice and coy, choosy, passive females.
When she first arrived at her Himba field site in Namibia in 2009, Scelza began a survey of the mothers she intended to interview, gathering their marital and reproductive histories. “Who’s your husband? Is he your first husband? How many kids do you have?”—the basics every anthropologist asks of her subjects in the field in order to get an accurate demographic portrait of the population. But Scelza quickly found herself having an experience not unlike Kim Hill’s with the Aché, many of whom told him, as he diligently worked on kinship charts, that they had more than one father. Early in the interview and data collection process, a woman informed Scelza, “This child is from my husband, and these two children are omoka.”
Confused, Scelza asked her Himba translator what the word meant.
It meant “to go to the far place to get water,” he explained.
Seeing the anthropologist’s confusion, the translator elaborated that “going to the far place to get water” might be a way of creating cover, so to speak, when heading off to a tryst. Omoka child means a child “from the far place we go to get water”—a child a married woman conceives during an affair, or one born out of wedlock. The women knew whether they were having omoka children by counting back from the day of their last menstrual period and figuring out whom they’d had sex with and when.
Scelza had read about polygyny among the Himba, and that the women had lovers just like the men did. But this term was something new. She continued to press her translator, who insisted that, yes, the term was in common usage since, after all, many married women had children by men other than their husbands. And sure, he told her, go ahead and ask the Himba anything you want about these arrangements and practices. Married men and women alike will speak to you openly about their lovers and who fathered which child, he assured her.
Scelza told me that at first she suspected she might be misunderstanding the meaning of the word omoka and all it suggested. But as she continued asking women about their marital and reproductive histories, many of them repeated the term omoka, confirming that the practice was far from uncommon. A married Himba woman who is pregnant, in other words, is likely to have become so by a man other than the one she is married to. And a married woman with a child may well have had it by a man other than her husband. And nobody seems to think much of it.
Scelza suspected that the number of omoka kids a Himba woman had could unlock some secrets about female infidelity more generally. For starters, unlike many Western industrialized populations where women can “conceal” sexual infidelity by not bearing a child thanks to birth control, in a natural fertility population like the Himba there will be a much closer match between rates of infidelity and rates of extra-pair paternity—rates of kids born to women married to men not their fathers. In the US and the industrialized West, for example, rates of extra-pair paternity hover between 1 and 10 percent. That’s very low, given that rates of female infidelity are thought to range anywhere from 13 to 50 percent in our world. From the Himba, for starters, Scelza could get a more unadulterated rate of female adultery to contribute to the worldwide ethnographic literature on women and extra-pair sex. And just as important, she might also be able to get information on why Himba women cheat.
First, though, Scelza had to figure out just how promiscuous Himba women were. The short answer was: very. She included 110 women in her analysis, recording 421 births. The women Scelza interviewed attributed each of their births to either her husband or an extramarital affair—an omoka birth. Scelza then classified each marriage as arranged or a love match. She felt confident of the women’s paternity assertions when she saw that the women’s calculations of when they became pregnant and by whom were supported by anthropologists’ records that married Himba couples often spend “significant periods apart.” In the end, Scelza determined that nearly 32 percent of the women in her sample had at least one omoka birth during her lifetime. Of the group of women who had at least one extra-pair birth, twenty had one, nine had two, and six had three or more omoka children with their lovers. Only 329 of the 421 births were from within wedlock. The long and short of it was that the Himba had the highest reported rate of extra-pair paternity of any small-scale society in the world: nearly 18 percent of all marital births were omoka. And just under one in three Himba women—nearly a third—had babies with their lovers while married.
But why? How can the Himba’s beliefs and practices be so different from ours—and what factors, precisely, contribute to their radically accepting view of not only female “promiscuity” but the bearing of omoka children?
Scelza knew going into her analysis that biology, ecology, environment, and culture all play a role in human behavior. The Himba’s comparatively relaxed attitude about extramarital sex was obviously a contributing factor in their tolerance of infidelity and omoka births. Himba women asked her repeatedly, “Brooke, why do you sleep alone all night in your tent?” When she replied that it was because she was married, they laughed or shrugged and teased her. “That doesn’t mean you can’t have a lover,” they insisted. “Aren’t you lonely in your tent by yourself, Brooke?”
But this belief that a “lonely” woman can and should take a lover regardless of whether she’s married didn’t emerge from thin air. Certain ecological and environmental factors create a context where the conviction that it’s normal for a married woman to have sex with a man who is not her husband can take root. “The Himba have few heritable resources,” Scelza told me, “and fathers do not invest heavily in kids.” These realities mean that men are at less risk of misdirecting energy and investment to children not their own. In addition, Himba children help out around the compound, becoming net contributors to the group at a relatively young age compared to kids in other contexts, like the industrialized West, where kids are costly and burdensome to their parents. These differences mean that Himba men are motivated to tolerate paternity uncertainty—basically because it costs them very little, and even benefits them in some ways. Kids do chores, herd, and generally offset the cost of their keep and then some. And a Himba man’s wife’s lover often drops off food for the omoka child, further lowering the “cost” to the husband.
In addition, Himba men do not pay a high bride-price for their wives; and their cows are not passed down patrilineally, a practice that would create the possibility that a father might bequeath his cows to another man’s child. For all these reasons, a Himba man has very little to lose if his wife has a lover or even a child by another man. Moreover, if a married man is at a remote cattle station with his girlfriend, the benefits of guarding his wife at home in order to prevent her from taking a lover of her own become prohibitive. It’s impossible to be in two places at once and extremely difficult to watch over an autonomous woman from a distance. It’s also pretty unpleasant to obsess over it. It is better and less “expensive” in every sense for a man to develop a tolerant attitude, and enjoy a girlfriend at the cattle station or in town who may, after all, bear him a child of his own. It also might serve him to have someone else watching out for his wife in his absence.
As for Himba women, specific social circumstances work in their favor as well when it comes to affairs and omoka children. While a Himba woman moves to her husband’s compound upon marriage, she usually maintains very strong ties to her own parents and siblings and other relatives, visiting their compound often. If she has co-wives, as many Himba women do, owing to more or less formal arrangements, they can watch her children and keep her husband happy while she visits with her family for days at a time, or while she gives birth and then recovers among her own kin. Where women have strong ties and access to their own kin in marriage, they have increased autonomy, including sexual autonomy. Among the Himba, the reality of the omoka child proves this is the case. And, Scelza told me, there are plenty of benefits for the Himba woman with a lover. If her husband is away and there is a drought and she needs to pay for supplementary food, or she needs to take a child or herself to the clinic, she has a larger circle of helpers. “Unlike the Upper East Side of Manhattan, where cheating is an incredibly risky strategy if you’re married to someone with high status and high wealth, for Himba women it makes complete sense and insulates against risk,” Scelza explained, making the importance of context dramatically clear and personal for me.
So why doesn’t every Himba woman of childbearing age have an omoka child?
In her research, Scelza discovered something else. Reviewing her data, she realized there were no omoka children born to women in love matches. Of the seventy-nine women she interviewed who had chosen their own husbands, not a single one had an omoka child. Meanwhile, there were omoka children in nearly a quarter of arranged marriages.
Far from the choosy, coy female that Darwin and Bateman imagined, or the specter of the more heavily invested mother who would naturally want quality over quantity, some Himba women assertively and actively exercise choice after their options have been circumscribed, Scelza concluded, going for both quantity and quality. In the face of coercion—being compelled to marry a man they have not themselves selected—their counterstrategy is to do what they are asked to do but also to do what they want. They have affairs. And then they have babies with their lovers. Omoka children and the high rate of extra-pair paternity among the Himba prove that Himba women are what Hrdy wants us to understand all primate females, including women, to be: not essentially retiring and naturally monogamous because of our biology but creatures who live at the intersection of biology and culture and ecology, making us “flexible and opportunistic individuals who confront recurring reproductive dilemmas and trade-offs within a world of shifting options.”
We might well think that if exerting their choice to have an extramarital relationship helps Himba women in arranged marriages achieve emotional and sexual satisfaction, it is reward enough. But there’s more to it, Scelza discovered. Himba women who have arranged marriages and then take a lover or lovers and bear their children actually improve their reproductive success. (Even when a young woman divorces her first husband, Scelza explained, he remains responsible for any children she bore during her marriage to him. Even if they are not his own. This makes an early arranged marriage a better deal than it may appear on the face of it.) Scelza documented that women in arranged marriages with lovers have more children who survive to age five than do the Himba women who marry the men they choose themselves. Clearly, mating multiply is beneficial to these women’s reproductive success.
Scelza, studying the Himba and when and why they “go to the far place to get water,” has served up a version of female choice that is strategic and far from sexually reticent, and presented us with a population where having “affairs” benefits women in terms of the number of helpers they have and the number of children they have. It is a glorious rebuttal to the Darwin-Bateman paradigm and a blow to the insistence that men and women are naturally one way or another socially and sexually because of who they are biologically. But one of the most important things about Scelza’s work with the Himba may be that it throws us a fascinating, unexpected, and richly suggestive curveball that forces us to continue thinking through female choice. Himba woman who exercise unconstrained choice, marrying the men they pick themselves and then choosing to stay true to them, have lower reproductive success. They may do what they want and stick with that independent, personal decision—and in so doing, they may potentially disadvantage themselves in the most basic and fundamental way, by having fewer children who survive to adulthood. Scelza was cautious about this detail when I asked about it. She pointed out that lower reproductive success and being monogamous might not be a simple equation, and there might be an implied causality in this instance “that we’re not sure of.” It’s possible, for example, that these monogamous women simply have lower fertility, or their partners do. But the possibility that monogamy may be straight up disadvantageous in particular contexts, including among the Himba, is a distinct, compelling, and game-changing notion.
Is monogamy a privilege or a prison for women? Is it a choice, or does it subvert choice? Is it a luxury or a deprivation? The lesson of the Himba and the omoka child is: it depends. On context. The interlocking, impossible-to-disentangle factors of biology, culture, and environmental circumstances mean sexual and social behaviors will be malleable; gamete production cannot explain or account for much beyond itself. For the Himba, cheating women who have had their hands forced by the choices of others come out on top in the game of reproductive success, while monogamy potentially disadvantages those women who are privileged enough to choose it, along with choosing their own husbands. This may be why, when I asked Brooke Scelza whether doing fieldwork among the Himba and speaking to those women about sex had changed her personal view on monogamy, she nodded. She joked about having two children under the age of four, and her work, and her marriage, and said that in addition to not wanting to hurt her husband, who, like her, lives in a culture that expects monogamy even as it winks about its improbability, she could not imagine adding an affair to the mix. Then she laughed and told me she loved her husband very much and wasn’t implying that were it not for being busy with kids and work, she would be having extra-pair dalliances—she didn’t mean that at all. “It’s more that in our society it’s hard to imagine having the bandwidth for that.” Then she said, with utmost care, “Well, it was. I used to think it was very straightforward. It was hard to understand women who felt differently than I did. Now I see that all of this is very, very complicated.”
Scelza’s remarkable achievement, among others, is helping us understand that “going to the far place to get water” or not going there, even in a context where there is comparatively little social censure or judgment about which you choose, is nevertheless a choice with surprising and profound consequences.