Women After All: Sex, Evolution, and the End of Male Supremacy (14 page)

Consider a pair of golden-white tassel-ear marmosets just before the female gives birth, a few steps ahead of a stalking jaguar that smells pregnancy in the night. After some failed attempts, she finds a tree with a large hollow not engaged by a raccoon or other forest denizen also in need of shelter from jaguars. At sunset she goes into labor, with contractions every five minutes. She squats and stretches
her body upward, convulsing a little and squeezing her eyes shut with each contraction. Her mate is nearby, waiting to assist as only marmoset males do. In less than an hour, the contractions begin to pulse quickly, and the first twin appears. She licks it as it emerges, and it soon clings to her chest. The male leans out of the hollow’s portal into the night, checking for predators. In a few minutes, the second baby is born, the male attentively sniffing it as it comes out. Soon he is chewing the two umbilical cords, eating them like long strands of spaghetti. Then he gorges on the placenta as the female licks the twins.

The next day, the four emerge and resume the forest trek. The twins cling to their mom while her mate grooms her, but for now she rebuffs his bids to hold his young. Soon they are joined by others in their extended family who have spent the night elsewhere. All show intense interest, sniffing and nuzzling the young, until finally the father’s prerogative is recognized, and the mom allows him to hold one. He cradles it tenderly. One young helper pulls the second twin off the mom but is soon in distress as she realizes it is clinging for dear life; her first babysitting gig ends as Mom relieves her. Within a few days, the father is carrying the twins almost all the time, giving them to the mother to nurse and to occasional helpers, who do help.

But this is not the case in most primates outside the marmoset family. Helpers in many species do little, and sometimes they do more harm than good. As for males, fathers or not (they often don’t know), their contribution is usually minimal.

Barbara Smuts, another brilliant primatologist of Hrdy’s generation, studied baboons on the African savanna. Not only are these ground-living monkeys much closer kin to us than lemurs or marmosets, they are highly successful—they’re considered vermin in some countries, a backhanded tribute to their adaptations—and they are large, dangerous, brainy primates with intricate social lives.
As such they’re a glimpse into how our remote ancestors may have adapted to life on the ground. Irven DeVore, a mentor of Smuts and Hrdy, had shown that in the wild, baboon males ruled in their very large troops—up to hundreds together—not by force alone but through alliances. (We did not know it then, but alliances were also common among females of many species.) You could figure out a dominance ladder by tossing a chunk of food between any two males. The results of all possible pair contests would then tell you which male could beat every other one-on-one, which could beat every other except the first, and so on down the pecking order—a term derived from birds, where it was all about who pecked and who
got
pecked.

But in these smart monkeys, that ladder from the experiment didn’t tell you who was in charge in real life, because baboon dominance demanded coalitions. It wasn’t whether Chuck could beat Sam in a one-on-one bout; it was whether Sam could rely on Joe and maybe Fred to join in. Chuck might be the strongest and most vicious, but if he couldn’t assemble an alliance, each of them would trump him as long as they didn’t get caught with him alone. Coalitions also helped protect the group from big cats and other African ground predators. Mothers with infants would stay in the center, juveniles would be nearby, other, weaker adults would gravitate toward them, and at the periphery teams of the biggest, strongest males would face down the threat.

In a species that grew up slowly, with much to learn about social life—friends, foes, faces, threats, coalitions, hierarchies—the mother-infant relationship gradually ushered the youngster into a fairly safe place in a complex social world. Play, too, had a major socializing role, as infants and juveniles tumbled energetically over one another. But baboons had to grow up male and female, did so at different rates, and ended up different sizes. Males were not only bigger and bulkier than females, they had much larger canine teeth, to scare and, at times, to tear.

They could threaten females, but they were especially hazardous to other males. Recall that in systems in which males can mate with many females—gorillas, for instance, where top males keep harems, or, in the extreme, elephant seals, where 4 percent of the males get 85 percent of the couplings—the biggest losers in evolution are not the put-upon females but the totally shut-out males. This is true to some degree in baboons, although as in many primates, there is a time dimension; males age out of power and breeding. While this might seem a rotation that in time gives access to all, males have to age
into
mate-worthy positions, and in many species this means male transfer at adolescence. When female kin are the core of the group, young males are pushed out as they near adulthood, and this is a dangerous time for them. Mortality is high. To survive well, and certainly to mate, they must be admitted to other troops, where the stronger, older, well-connected, strange males don’t want them, any more than their dads and uncles did back in their home troops.

Smuts discovered a marvelous workaround used by young male baboons trying to break into such a brave new world. They couldn’t get close to sexually receptive females, who were monopolized by dangerous resident males, but they were able slowly to get to know females with infants. In her remarkable book
Sex and Friendship in Baboons,
Smuts described the pattern in quantitative detail. It’s the opposite of the langur case. There, the new males are young but strong adults, and they confront the older local males first. If they win, they go after infants with a vengeance and, in due course, mate with their mothers. Baboon male strangers, in contrast, sidle up to moms with infants, hanging out at a safe distance with postures and facial expressions that say, “No threat.” Over time they move closer, begin to groom the mother, and finally touch and hold the infant.

All the while, any aggression from the established males is dampened by the nearness of the infant. This “agonistic buffering” occurs in many primates, where weaker males or females protect themselves by borrowing infants. This is often dependable insurance
against attack. But in many months of study, Smuts got to know her subjects well; she found that the females who befriended the young males were hedging their bets. Ultimately these males could become not just pals but protectors, and maybe even lovers. In evolutionary terms it was a win-win; males were gaining tolerance and gradual acceptance in what could have been a deadly new troop, while the females were optimizing the number of fathers. If these were friends with benefits, the benefits were mutual and might last a lifetime.

So even when dominated by larger males, females can gain advantages in survival, offspring protection, and mate choice—including multiple mates—by subtly deploying power over time. Many
female
alliances achieve similar ends in the face of male threats; but here was a female-male alliance based on a young mother’s tolerance and indulgence of a new, vulnerable, supplicant male.

Smuts knew, though, that this rather sweet and, for females, empowering process was not the only way baboon males approached females; scattered throughout the primate world were much nastier patterns. In 1993, she and her father, Robert Smuts, wrote a paper on male sexual force in primates that was as much of a turning point as Hrdy’s work on infanticide. Such coercion, the father and daughter found, was widespread in primates and mammals generally. This was not unknown, but their systematic overview stimulated a great deal of further research, much of it gathered in a 2009 book edited by primatologists Martin Muller and Richard Wrangham. Some male coercion has a short-term goal, but some results in long-term relationships; some seems designed only to persuade, while some results in very serious injury.

Reports by other primatologists are ongoing. Nicole Gibson and her colleagues recently published a case of rape among Peruvian spider monkeys. We know them as graceful acrobats that seem to fly through the forest using their long tails as a fifth grasping limb. But in one less-than-graceful case a female was set upon by a male
who “approached fast, crashing through the canopy.” She escaped, but he chased and attacked her stubbornly for ten minutes. The fight involved “cuffing”—hitting her on the head repeatedly with his arm—“and fierce wrestling.” She screamed and whined; he growled. She “dropped down to a low vine next to the tree trunk, but [he] pinned her to the vine and started to copulate.” She defecated twice, something females never do during normal sex but often do when attacked. She scrambled up the tree, but he quickly caught and entered her again. He ejaculated and stayed in her for two minutes, until she finally squealed and jumped away from him.

Such forcing is unusual for spider monkeys, and the perpetrators are likely to be less successful males. Importantly—and in all species with male sexual coercion—females have ways of avoiding it. One is to form consortships with males they like, perhaps going off into the forest away from others for a period of days to mate privately. Or, when they are sexually receptive and mate in a group setting, they may immediately mate with other males, confusing them all about paternity and thus protecting their infants from infanticide. Here as throughout primate evolution (our own included) females have had options, but through no fault of their own, the options didn’t always work.

In orangutans—the great apes of Sumatra and Borneo—forced copulation appears to be more like the rule than the exception. A female and her young live mainly as a single-parent family until a male shows up. She prefers older, larger, more experienced males, but as she ranges through the forest she may encounter younger, more aggressive ones. These oversexed, frustrated, bullying subadults may not take no for an answer, and although they may be only half the size of mature males, they can gang up on a victim and overpower her. She’s most at risk when, after years of nursing, she begins to be fertile again.

ElizaBeth Fox wanted to know what females do about it. She spent nine thousand hours over two years watching wild Sumatran
orangs and saw more than 200 copulations. Of the 141 that involved subadult males, 99 percent were male-initiated, and females resisted at least a third of them. Orangutan females try to keep harassment to a minimum by hanging out with mature males—the only ones
they
initiate sex with. Yet these associations are not always sexual, at least not in the short term. Females hang with older males for protection, and this keeps thuggish teens at bay. In 2010, Cheryl Knott and her colleagues studied Borneo orangs, refining Fox’s work. By analyzing the hormones in the orangs’ urine, they knew when the females were fertile, and this was when females actively sought mature males. The females couldn’t avoid unwelcome advances at other times, but resistance was usually futile anyway. It was a good way for females to confuse young males about who the father was and reduce the chance of infanticide by these same bullies. Meanwhile, they got a fair chance of choosing the father they wanted.

This also turns out to explain female toleration of male bullying in other primates with larger and stronger males. Interestingly, Joyce Parga and Amy Henry reported on an event among our old friends the female-foremost ring-tailed lemurs—a rare case of sexual bullying that, paradoxically, proved the rule. A male tried to force himself on a pubertal female having her very first estrus, achieving penetration despite her struggles against him. She showed her preference for other males by presenting to them, but she rejected this one—a known loser with very low mating success. Parga and Henry think his behavior, rare in ringtails, was due to human food provisioning (the group was not completely wild), which made this young female come into estrus early; she had not yet grown into full command over males. So the ringtails keep their reputation of female rule, despite a dud male forcing the equivalent of a young teen. She no doubt went on to learn how to keep such fellows in line.

If you’re getting the idea that females dominate in primate studies almost as much as in lemurs, you are not far off, at least for Western
primatology. Jane Goodall, Dian Fossey, and Biruté Galdikas largely put the field on the map in the 1960s with classic studies of chimps, gorillas, and orangutans. Among other outstanding fieldworkers who followed, aside from Hrdy and Smuts, were Jeanne Altmann, Shirley Strum, and Joan Silk on baboons, Anne Pusey on chimps, Dorothy Cheney on vervet monkeys, Karen Strier on muriquis, Linda Marie Fedigan and Katherine MacKinnon on capuchin monkeys, Meredith Small on macaques, Alison Jolly, Alison Richard, Patricia Wright, and Patricia Whitten on lemurs, and many others—not to mention Sue Savage-Rumbaugh, whose work on the mental capabilities of captive chimps and bonobos transformed our ideas about language and the mind. As for the coming generation, it is estimated that four out of five Ph.D.s under way in primatology will go to women. It’s been said that primatology done by women is inherently feminist, but these women’s goal was to advance science—although they may well have noticed things about sex roles that men missed. It’s not that men haven’t mattered to the field; they have—Japanese primatology, in particular, has remained a mostly male domain, and other men have done important primate fieldwork. But women have made an exceptional impact from the outset.

None more than Jane Goodall—now a conservationist and cultural icon—whose bold and brilliant research on the chimpanzees of Tanzania’s Gombe Stream Reserve during half a century made everyone think anew about the boundary between us and animals. She described their individuality, sensitivity, depth of feeling, relationships and communities, devoted mothering, lifelong family ties, respect for elders, ability to make and use tools and pass on traditions, cooperation during hunts and meat-sharing afterward, and many other aspects of their lives that seemed, well, human. But as she later admitted, her initial picture of chimps made them seem a pristine and nearly idyllic version of almost-human life.
In the Shadow of Man
was the title of her first book about them, and it emphasized the vulnerability of these apparently gentle creatures in the face of human violence and greed.