by Carl Sagan
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A mother and her adult daughter who have been foraging separately for a few hours may merely look at each other and give a few grunts when they meet; but if they have been separated for a week or more, they are likely to fling their arms around each other with grunts or little screams of excitement, then settle down for a session of social grooming.15
Chimpanzee females and their young have deep bonds of affection, while the adolescent and adult males seem more often mesmerized by rank and sex. The young revel in rough-and-tumble play together. Infants whimper and scream if they find themselves out of sight of their mothers. Youngsters will come to the aid of their mother if she is being attacked, and vice versa. Siblings may show each other special, affectionate consideration throughout their lives, and take care of the young during childhood if—as is common—the mother has died before the children are grown. Occasionally chimps of either sex will endanger themselves to help others, even those who are not close relatives. Male bonding on a hunt or patrol is palpable. Clearly there are opportunities—especially when the testosterone titers are low—for civil, affectionate, even altruistic behavior in chimpanzee society.
Adult males, despite the dominance hierarchy, spend considerable time alone. After the birth of their first baby or two, most females spend their entire lives with others. So females are both required to develop more refined social skills and have more opportunity to do so. As is usual among monkeys and apes—with rare exceptions—only one child is born at a time. Except when they’re in estrus, their time is spent mainly with the children. This is key for the next generation: As we’ve mentioned, apes and monkeys that are not regularly cared for, nursed, held, fondled, and groomed by an adult tend to become socially awkward, sexually inept, and disastrous as parents when they grow up.
Females are not born knowing how to be competent mothers; they must be taught by example. The investment of time required of the mother is substantial: The young are not weaned until they’re five or six years old, and enter puberty around age ten. For much of the time until weaning they’re unable to care for themselves. They’re very good, though, in clutching their mother’s hair as they ride upside-down on her belly and chest. So long as they allow the infant to nurse whenever it wants, perhaps several times an hour, chimp mothers are usually infertile, and unattractive to males. This is called “lactational anestrus.” Without the males constantly hassling them for sex, they’re able to spend much more time with the kids.
Chimp mothers use corporal punishment only very rarely. Infants learn the conventional modes of threat and coercion by closely observing older male role models. Infant males soon attempt to intimidate females. This may take some effort; females, especially high-status females, may not take kindly to being bullied by some young whippersnapper. The upstart’s mother may help him in his efforts at intimidation. But before reaching adulthood nearly every male has obtained submission from nearly every female. Nursing male infants—including those still years away from weaning—routinely and successfully copulate with adult females. Adolescent males emulate adult males carefully (aping every nuance of their intimidation displays, for example), wish to be their apprentices and acolytes, are simultaneously nervous and submissive and hopeful in their presence. They’re looking for heroes to worship. It even happens that an adolescent who’s been cruelly attacked by an adult male will leave his mother and follow the aggressor everywhere, submission signals flashing, longing for acceptance at some future and glorious time.
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From a human perspective chimpanzee social life has many nightmarish flourishes. And yet, despite its excesses, it’s hauntingly familiar. Many spontaneous groupings of men are oriented around hierarchy, combat, blood sports, and loveless sex. The combination of dominant males, submissive females, differential but scheming subordinates, a driving hunger for “respect” up and down the hierarchy, the exchange of current favors for future loyalty, barely submerged violence, protection rackets, and the systematic sexual exploitation of all available adult females, has some marked points of similarity with the lifestyles and ambiance of absolute monarchs, dictators, big-city bosses, bureaucrats of all nations, gangs, organized crime, and the actual lives of many of the figures in history adjudged “great.”
The horrors of everyday life among the chimpanzees recall similar events in our history. We find humans behaving like chimps at their worst in endless succession in the daily press, in modern popular fiction, in the chronicles of the most ancient civilizations, in the sacred books of many religions, and in the tragedies of Euripides and Shakespeare. A summary of human nature based on the plays of Shakespeare would define “man,” wrote Hippolyte Taine, as
a nervous machine, governed by a mood, disposed to hallucinations, transported by unbridled passions, essentially unreasoning … and led at random, by the most determinate and complex circumstances, to pain, crime, madness, and death.16
We’re not descended from chimps (or vice versa); so there’s no necessary reason why any particular chimp trait need be shared by humans. But they’re so closely related to us that we might reasonably guess that we share many of their hereditary predispositions—perhaps more effectively inhibited or redirected, but smoldering in us nevertheless. We’re constrained by the rules that, through society, we impose on ourselves. But relax the rules, even hypothetically, and we can see what’s been churning and fermenting inside us all along. Beneath the elegant varnish of law and civilization, of language and sensibility—remarkable accomplishments, to be sure—just how different from chimpanzees are we?
For example, consider the crime of rape. Many men find depictions of rape arousing—especially if the woman is portrayed as enjoying it despite her initial resistance. Most American high school and college students (of both sexes) believe that a man is justified in forcing a woman to have sex—at least when the woman behaves provocatively.17 More than a third of American college men acknowledge some propensity to commit rape if they were guaranteed they could get away with it.18 The percentage goes up if some euphemism such as “force” appears in the question instead of “rape.” The actual risk of an American woman being raped in her lifetime is at least one chance in seven; almost two-thirds of the victims have been raped when they were minors.19 Perhaps men in other nations are less fascinated with rape than Americans are; perhaps mature men, with lower testosterone titers, are less comfortable with rape than adolescents are.20 But it would be hard to argue that there’s no biological predisposition for men to rape.
While a range of causal factors have been proposed, most rapists turn out to be not slavering psychopaths, but ordinary men given the opportunity and acting on impulse,21 sometimes repeatedly and compulsively. Some students of the subject see rape as a biological strategy (entered into without his conscious understanding) to propagate the rapist’s genes;22 others see it as a means for men (again largely unconsciously) to maintain through intimidation and violence their domination over women.23 The two explanations do not seem mutually exclusive; and both seem to be operative in chimp society. Also, a significant minority of women are aroused by fantasies of rape, and, in one study, women who have been raped by an acquaintance seem disturbingly more likely to continue dating their assailants than those who were subjected only to attempted rape by an acquaintance.24 This is at least reminiscent of the compliance pattern of female chimps.
Over a set of hereditary predispositions human society lays down a kind of stencil that permits some to be fully expressed, some partially, and some hardly at all. In cultures where women have roughly comparable political power with men rape is rare or absent.25 However strong any genetic propensity toward rape might be, social parity appears to be a highly effective antidote. Depending on the structure of the society, many different brews of human proclivities can be elicited.
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Chimpanzee society has an identifiable set of rules that most of its members live by: They submit to those of higher rank. Females defer
to males. They cherish their parents. They care for their young. They have a kind of patriotism, and defend the group against outsiders. They share food. They abhor incest. But they have, so far as is known, no lawgivers. There are no stone tablets, no sacred books in which a code of conduct is laid out. Nevertheless, there is something like a code of ethics and morals operating among them—one that many human societies would find recognizable and, as far as it goes, congenial.
* Among the males. Among their own gender, females may carry grudges for years, and refuse to be reconciled.
* That this might have something to do with sex was first proposed, in the face of considerable Victorian skepticism and unease, by the ever-insightful Charles Darwin.6
* Similar behavior is known among other social animals—in gorillas, for example, where the alpha permits a female to mate with lower-ranking males, but only if she’s pregnant. Among wolves, only the alpha male and the alpha female breed, but the female mates with other members of the pack when she’s not in heat.8
* This is not just an unpleasant circumstance of chimpanzee life; it occurs among gorillas, baboons, and many other apes and monkeys. Over a fifteen-year-long study of gorillas near the Virunga volcano in Rwanda, more than a third of all infant mortality was directly due to killing by gorilla males. Infanticide for them is a way of life.11
* Something similar is observed in other, quite different non-monogamous species—for example, hedge sparrows. The alpha male works hard to prevent copulation by betas, but only in the females’ fertile period. However the female, even in the fertile period, may dart away on occasion for surreptitious matings with the betas. Only in this case will a beta help feed her chicks. Again the females are using male preoccupation with sex to induce them to help her little ones.12
* A sperm that carries the smaller Y chromosome—the one that makes a male—weighs slightly less than one that carries the bigger X chromosome that makes a female; if lighter sperms travel faster, this may be why slightly more males are conceived than females.
Chapter 17
ADMONISHING THE CONQUEROR
Perhaps no order of mammals presents us with
so extraordinary a series of gradations as this
[step by step, from humans to apes to monkeys
to lemurs]—leading us insensibly from the
crown and summit of the animal creation down
to creatures, from which there is but a step, as
it seems, to the lowest, smallest, and least
intelligent of the placental Mammalia. It is as if
nature herself had foreseen the arrogance
of man, and with Roman severity had provided
that his intellect, by its very triumphs, should
call into prominence the slaves, admonishing
the conqueror that he is but dust.
T. H. HUXLEY
Evidence as to Mans Place in Nature1
The Archbishop of York is Primate of England. The Archbishop of Armagh is Primate of Ireland. The Archbishop of Warsaw is Primate of Poland. The Pope is Primate of Italy. The Archbishop of Canterbury is Primate of the planet, at least as far as his Anglican communicants are concerned. These ancient titles come from the medieval Latin word primus, which in turn derives from older Latin words meaning “principal” and “first.” The ecclesiastic use was straightforward: A primate of a region was the chief (“first”) of all its bishops. In recent centuries the title has devolved often to little more than an honorific. Other titles have taken precedence. But “Prime Minister” and “President” and “Premier” come from similar linguistic roots, all meaning “first.”
When Linnaeus was drawing up the family tree of life on Earth he was, as we’ve noted, afraid to include humans among the apes. But despite widespread opposition, it was impossible to deny some deep connections of monkeys, apes, and humans.* So all were classified into the order (for him, one taxon higher than genus) that he called primates. Scientists who study non-human primates—of course, they’re all primates themselves—are called primatologists.
This other meaning of “primate” also derives from the Latin for “first.” It’s hard to see by what standard a squirrel monkey, say, could be considered “first” among the lifeforms of Earth. But if a case is made that humans are “first,” then the tarsiers, bushbabies, mandrills, marmosets, sifakas, aye-ayes, mouse lemurs, pottos, lorises, spider monkeys, titis, and all the rest are dragged in along with us. We’re “first.” They’re our close relatives. So they, in some sense, must be “first” also—an undemonstrated and suspect conclusion in a biological world that runs from virus to great whale. Perhaps, instead, the argument goes the other way, and the humble status of most members of the primate tribe casts doubts on the lofty title we have appropriated to ourselves. It would make things so much easier for our self-esteem if those other primates weren’t—anatomically, physiologically, genetically, and in their individual and social behavior—so much like us.
Surely there is at least a hint in the word “primate,” not just of self-congratulation, but of the idea, fully realized in the practices of our own time, that we humans arrogate command and control of all life on Earth into our own hands. Not primus inter pares, first among equals, but just plain primus. We’ve found it convenient, even reassuring, to believe that life on Earth is a vast dominance hierarchy—sometimes called “The Great Chain of Being”—with us as the alphas. Sometimes we claim that it wasn’t our idea, that we were commanded by a Higher Power, the most Alpha of Alphas, to take over. Naturally, we had no choice but to obey.
About two hundred species of primates are known. Conceivably, in the quickly dwindling tropical rainforest another species or two—nocturnal or elegantly camouflaged—may have so far escaped our notice. There are about as many species of primates as there are nations on Earth. And like the nations, they have their different customs and traditions, which we sample in this chapter.
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Take the baboons—“the people who sit on their heels,” as the !Kung San people of the Kalahari Desert respectfully call them. Hamadryas baboons are different from savanna baboons (from whom they diverged perhaps 300,000 years ago), and free baboons behave very differently from baboons crowded together in zoos (the latter “insolently lascivious,” as an eighteenth-century naturalist described them). One telltale trait they all have in common: Sharing meat is virtually unknown among baboon males of either species, although it’s fairly widespread among the chimps.
At sunrise the baboons rouse themselves from their sleeping cliffs and break up into a number of smaller groups. Each group wends its separate way over the savanna, foraging, scampering, playing, intimidating, mating—all in a day’s work. But at the end of the day, all the groups converge on the same distant waterhole, and it may be a different waterhole on different days. How do the groups, out of sight of one another for most of the day, know to wind up at the same waterhole? Have the leaders negotiated the matter as the sun was rising over the sleeping cliffs?
Adult male hamadryas baboons are almost twice as large as the females. They display a leonine mane, enormous, almost fanglike canine teeth, and a ruthless character. These males were deified by the ancient Egyptians. They utter deep and prolonged grunts as they copulate. Their faces are “the color of raw beef steak—as different from the mousey grey-brown females as if they belonged to two different species.”2 As females approach sexual maturity, they are chosen by particular males and herded into harems. Squabbling among competing males over ownership of the females may have to be worked out. A high priority of the males is maintaining and improving their status in the dominance hierarchy.
Hamadryas harems characteristically comprise from one to ten females; the males are concerned to keep peace among the females and to make sure that they do not so much as glance at another male. This is a bondage with little hope of escape. A female must follow her male about for the rest of her days. She must be sexually submissive: the least reluctance and she
is bitten in the neck. It is not unknown for a hamadryas female to have her skull punctured and crushed in the massive jaws of the male for a minor infraction of the behavioral code he ruthlessly enforces.3 Conflict and tension around her are high when she’s ovulating, and somewhat muted when she’s pregnant or nursing the young. Unlike the chimps, you can see sexual coercion in the very posture of the baboon copulatory style: The male typically grasps the female’s ankles with his prehensile feet while mating, guaranteeing that she cannot run away. Compared to hamadryas behavioral norms, chimps live in an almost feminist society.
In a quarrel among females, one will sometimes threaten her rival with her teeth and forearms and, at the same time, alluringly present her rump to the male; with this postural offer of a deal, she sometimes induces him to attack her adversary. Subordinate male savanna baboons, as well as barbary apes, may use an infant—an unrelated infant, a bystander infant, or maybe an infant he is baby-sitting—as a hostage or shield or placatory object when approaching a high-ranking male. This tends to calm the alpha down if he’s in a grumpy mood.
