Most competition in animals is with members of the same species. How could it be otherwise? They have almost precisely the same habitat, the same tastes in food, the same erotic aesthetic, the same nesting and sleeping places, the same foraging and hunting grounds. If the animals are spread out, there’s enough food and other resources for everyone, while they can still remain near enough so they can find each other when it’s time to mate. If they’re crowded together, conflict escalates and even the strongest animals run an increased risk of lethal combat.

Spreading out is accomplished by aggression, but aggression is not the same as violence and rarely goes as far as violence.8 Often it’s enough to announce menacingly to all within earshot that this is your territory and no intruders will be tolerated. You might patrol the frontiers, spraying your urine or depositing your feces in prominent, strategic locations—or leaving, through special scent glands and much dragging and rubbing, an aromatic token of your proprietary interest. If you’re a grizzly bear, you might try marking a pine tree as high up as you can reach; when potential poachers grasp how big you must be to mark so high, they’ll give you wide berth.

About 80% of the different orders of mammals are armed with specialized scent glands. Gazelles have them in front of their eyes, camels on their feet and neck, sheep on their bellies, some pigs on the wrist, chamois behind the horns, pronghorns on the jaw, peccaries on the back, musk deer in front of the genitals, and goats on the tail. Water voles rub their hind feet over their flank gland and rhythmically drum them on the ground. Gerbils and woodrats rub their bellies directly on the ground, secreting their scent mark from a ventral gland. Some animals have five or six different kinds of scent glands in various places on their bodies, each conveying a different chemical proclamation. Cats spray carefully titrated amounts of urine on the drapes and upholstery, in case some presumptuous alien feline might enter the living room and curl up before the fire. Rabbits meticulously deposit piles of feces, each pellet coated by the anal scent gland, at crossroads in the warren—like the altars of Hecate on the highways of ancient Greece.

Some animals mark others with these scents, and rats urinate on their partners’ bodies—perhaps as a sign of proprietorship over individuals as well as territories. Animals can distinguish male and female, their own group or strain from others, age, individual identity, and the sexual receptivity of females, all by odor alone.9 Scientists have begun to decipher the stock phrases of their chemical communications—maybe just “foreigners keep out: this means you,” or “single male, well-bred, wishes to meet attractive single female …,” or “for a good time, follow this scent trail.” Sometimes it seems to be something much more subtle. Animals are busy filling the olfactory communications channels with a richness and fineness of discrimination long ago lost to humans. With all our instruments, we have not yet learned how to reenter that world.

If, despite all your aromatic notices, someone invades your territory, it might be enough to make threatening gestures, or swoop down on him, or bare your teeth and growl. Clearly, claw-to-claw or talon-to-talon mortal combat each time there’s a minor jurisdictional dispute is too costly for everybody—winner and loser. It’s much better to disperse the population through bluff, deception, feints, and a vivid pantomime of what violence you will visit on the intruder should he persist in ignoring your restrained and reasonable warnings. Deterrence is the way these matters are arranged, by and large, on the planet Earth. Real violence lies at the extreme end of the spectrum of aggressive possibilities, a last resort, as Hobbes said. Nature almost always settles somewhere short of that.

To avoid misunderstandings, it’s important to have evolved unambiguous conventions not only for what constitutes aggression, but also for what constitutes submission. Typical submissive gestures in mammals are the opposite of typical aggressive gestures10—averting the eyes so they look anywhere but at the adversary; absolute motionlessness; a kind of bowing in which the forelegs and head are lowered and the rump raised; hiding from view those body parts that are conspicuous in threat displays; and turning jugular vein or belly up, exposing vital organs to the adversary as if inviting evisceration. The pantomime is lucid: “Here is my belly, do with me as you will.” It’s followed almost always by a magnanimous gesture from the victor.* Different species have different hereditary conventions on what constitutes and symbolizes submission. Fighting is transformed into ritual; instead of bloody combat, there is an exchange of data.

Such aggression—most often between males of the same species in disputes over territory or females—is very different from predatory aggression, aggression against members of another species. The two modes share some features in common (baring the teeth, for example), but the one is mainly bluff and the other is in deadly earnest. They engage different parts of the brain. In rivalries of love, cats will hiss, spit, arch their backs, make their hair stand on end, raise their tails high, and dilate their pupils. (Note how many of these postures and gestures make the animal seem larger and more dangerous than it is.) They rarely do each other serious harm, though. A genetic propensity for attacking others of your species, and eliciting attacks from them, has a maladaptive side to it—even if you win every fight, you might be badly injured, or a minor cut might later become infected. Bloodless rituals and symbolic combat are far more practical.

Predatory aggression is just the opposite. Its early object is to come as close as possible to the victim before it realizes what’s up. The cat will slink an inch at a time if it must, ears slicked back, hair tightly following the contours of the body, tail lowered. It stalks in absolute silence. Then the pounce, the kill, and dinner—all done with consummate delicacy and grace. No hissing and spitting here. Intraspecific aggression is almost all show, display, intimidation, coercion, stagecraft. Only rarely does it end in mortal combat. Interspecific aggression, that’s different. That’s business. The prey may get away, but the predator’s intent is murder. Few species systematically confuse the two modes of aggression.

Mock combat is a staple in the theater of intraspecific aggression; both parties go through the motions, but neither is seriously hurt. The deadly, needle-toothed piranha fish of South American rivers fight among themselves, or at least the males do, but never by biting: If there were biting, everyone could get hurt. Instead they push and shove with their tail fins. They want to communicate aggression, but not to bloody the water. It’s as if the combatants walk a fine line between cowardice and murder. Most often—crowded conditions may be another story—the line is walked with astonishing precision. But, as a reminder of how fine the line is, in many species intraspecific fighting is more likely when the animals are hungry. One kind of behavior spills over into the other

The female blue heron hears the love screech of the male. There may be several males calling at once—to the wind, for all they know. She picks her heart’s desire and settles on a branch nearby. The male immediately begins to court her. The moment she indicates interest and approaches him, though, he changes his mind, becomes unpleasant, shoos her away, or even attacks her As soon as the discouraged female flies off, he screeches after her—“frantically,” according to Nikko Tinbergen, the pioneering chronicler of blue heron life. If she gives him another chance and flies back, he may very well attack her again. Gradually, though, should the female’s patience last that long, the fickle male’s grumpiness subsides and he may actually be ready to mate. He is conflicted and ambivalent. Sex and aggression are mixed up in his mind, and the confusion is so profound that, if not for the patience of the female, this species might fail to reproduce itself. If ever there was an avian candidate for psychotherapy, the male blue heron is our nominee. But a similar confusion in the minds especially of males holds for many species, including reptiles, birds, and mammals. Some of the brain’s neural circuitry for aggression seems dangerously cheek by jowl with the neural circuitry for sex. The resulting behavior is strangely familiar. But of course humans are not herons.

Often you can see the ambivalence, the tension between inhibiting and disinhibiting the aggressive machinery in the animal’s behavior. It is literally “of two minds” A fighting cockerel, whose pecks and spurs are deadly, may in the midst of a confrontation turn aside and peck at a pebble on the ground, which after a moment it drops. In human as in animal behavior this is called “displacement.” The aggressive feelings are transferred or displaced to someone or something else, so the passions can be discharged without causing real injury. The cockerel is not angry at the pebble, but the pebble is a handy as well as a safer target.

Some male tropical fish use their vivid coloration to keep other males away, that is, to protect territories and females. The females are, however, similarly decorated. During courtship the female, if attracted to the male, dispenses with her usual indications of submissiveness or readiness for escape and signals her amorous intent by a display to the male—a display, however, which is very similar to the male’s own aggressive posture. In some species, the male becomes enraged (and probably a little confused); he responds by displaying his coloration broadside to her, beating his tail fearsomely, and charging her. But, as noted in a famous study by Konrad Lorenz, he does not actually attack her. (If he did, he would leave fewer offspring.) Instead, narrowly missing the female, he races on and attacks someone else, usually the male in charge of the next territory, who may have been minding his own business, browsing in the algae. Eventually things settle down. Our protagonist no longer attacks his neighbor or charges the female. The species continues. Here, instead of displacing aggression away from a formidable enemy to an inoffensive target, the displacement goes the other way around. This sort of redirection is widespread. Again, gestures, postures, and displays about sex are very close to those about violence. The two can get confused.

One wolf will greet another by placing its mouth around the other’s muzzle. Many other mammals do likewise. Those taming wild animals may be startled when they are at the receiving end of such a greeting. The wolf stands on its hind legs, places its forelegs on the scientist’s shoulders, and places its jaws around the scientist’s head. This is just the wolf’s way of being friendly. If you’re an animal who doesn’t know how to talk, a very clear signal is communicated: “See my teeth? Feel them? I could hurt you, I really could. But I won’t. I like you.” Once more, a very narrow line separates affection from aggression.

Chimpanzees engaged in what humans call horseplay put on a characteristic “playface” to show that their combat gymnastics are meant only as a game. Courtship displays in gulls have been described as “fear and hostility, or attack and fleeing tendencies, expressed … in a manner that denies them.”11

In cranes there’s an “appeasement ceremony” in which the male spreads his wings, exaggerates his size, raises his beak … and then, still in a threat posture, turns himself aside—presenting a vulnerable and very visibly marked part of his anatomy, perhaps the side or back of his head. The pantomime may be repeated several times and incorporate an attack on a piece of wood or something else handy. The message being communicated is clear. “I am big and threatening, but not toward you—toward the other, the other, the other.”12

Smiling may have a similar origin. Baring one’s teeth carries the message. “I think you’re food,” or at least “Watch out for me.” But in the symbolic language of animals, this signal may be softened and altered: “Even if you are food, even though I’m well-equipped to eat you, you’re safe with me” All over the world, in virtually every human culture, smiling signifies affection and good fellowship (with certain nuances conveying a touch of nervousness and deference). All over the world, in nearly every human culture, in civilian as well as military life—in handshakes, high fives, salutations among mounted Sioux, hails to Caesar and heils to Hitler, upon greeting a superior officer or waving farewell—we humans offer our right hands in greeting, demonstrating while still at a safe distance that we are unarmed and therefore pose no threat. In a species given from its earliest days to clubs, knives, spears, and axes, this is information worth having.

——


With occasional exceptions, animals do not seem consciously to work out what to do in a given situation and then, weighing alternatives, opt for aggression. It’s too slow a process to survive the hurly-burly of the biological world. Instead, the animal senses threat or prey, and a tenth of a second later it responds A complex set of physiological reactions begins—adrenaline pours into the bloodstream, limbs begin to flex—reactions that are ordinarily sitting there in the animal on ready standby, awaiting the release signals

In the neural architecture of mammals there is hardwired circuitry for aggression and predation. When a certain region in the brain of a solitary cat is electrically stimulated, she begins to stalk imaginary prey. Turn the current off and she stretches and licks her paws; the hallucination has vanished. Rats that do not look twice at a mouse will, when an electric current is made to pass through the appropriate parts of their brains, become crazed killers—dedicated, implacable mouse-murdering machines. The stimulated neural circuits are present for a reason; in the ordinary course of the animal’s life, they will be excited by some cue from the outside world—a motion, a smell, a sound, causing an electrical stimulation—and the brain machinery for aggression or predation is set into motion. When given a juicy bone still covered with meat, even puppies as young as two weeks old will growl and bark. Dry dog food does not trigger the same hardwired and impassioned response. Humans have such machinery too. Sometimes a misfiring or miswired circuit can set it into motion with very little stimulus from the outside world, or even none at all.

It’s as if all of us birds and mammals—but especially the males—are walking around wearing a control panel with a set of push buttons on it. The panels are prominently displayed, easy for others to get to (or even for us to get to—so we can pump ourselves up on our own, a skill of professional athletes). When pressed, the buttons disinhibit a set of powerful, passionate, and sometimes deadly responses that are ordinarily kept under tight controls. Put this way, it may seem odd that Nature has made the buttons so easy to push, so readily available, so vulnerable to exploitation.13

A cannibalistic species of firefly simulates the color and frequency of the come-hither flashes of another, country bumpkin species of firefly. The love buttons have been pushed on the naive insects; they see visions of sultry females where there is only a gaping mouth. To lure uninterested or recalcitrant females into mating, males of many species are often ready to press buttons designed for quite different purposes,such as feeding, defense, timidity in the face of aggression, or brood care. They may give a brief threatening lunge, cry like a baby, mimic an alarm call, hop on one leg as if wounded, or (as in peacocks) peck at the ground as if food has been found.14


Undeterred by scruple, they will use any method that works. In many cultures, young men try to press all available buttons for sex, perhaps offering wholly insincere promises of fidelity and devotion; or they taunt each other into fighting by casting aspersions on another’s courage, say, or his mother’s sexual behavior. The benefits of having these buttons so readily available must outweigh the risks. The inflexibility of such hair-trigger responses might be a cause for worry, though.

These behavior patterns also are encoded in the nucleic acids. Every deterrent flourish, every postural hint of submission, is meticulously written down in the ACGT language. That being the case, you might expect variations in the style or intensity of aggression from animal to animal within a given species, as is indeed the case. If you take a population of mice and breed the aggressive ones with each other and the peaceful ones with each other, eventually you produce two strains of markedly different temperament. This isn’t due to pup-rearing practices, because the young of aggressive parents, when raised by peaceful mothers, are aggressive, and vice versa. It’s a commonplace that through artificial selection dog breeders have produced nervous, high-strung, ferocious breeds—for example, rottweilers or pit bulls—and friendly, peaceful strains, often useless as watchdogs, such as cocker spaniels. In mouse and dog aggression, heredity often seems to take precedence over home environment. (It might be the other way around in humans, or the two influences might be evenly matched.)

——


Nearly all the social mammals are organized as groups of females (often relatives) with their offspring. Males, otherwise absent, are conspicuously present when the females are in heat They may be busy dominating, fighting, or mating, but in terms of basic social structure and the bringing up of the young, they are often a shadowy presence. Usually, the young are raised by single mothers. Among the exceptions to this rule are chimpanzees, gorillas, gibbons, wild dogs, perhaps wolves. And, more than occasionally, humans.

In temperate and polar climates, there’s a good reason for the young to be born in the spring—so they may have the rest of spring and all of summer and autumn to grow up before having to face the rigors of winter. If the gestation period is short (or alternatively around a year), then mating will also occur in the spring. To arrange for biological clocks to be built into animals, to stimulate the reproductive machinery at the right moment in springtime and to inhibit it at other times of the year, must have occupied great vistas of evolutionary time.

Natural selection has provided a wide range of visual, olfactory, auditory, and other cues to inform the normally uninterested males of the otherwise indetectable fact that ovaries are releasing eggs all around them. Sexual attention at other times is generally a wasted effort (it’s used to bond male and female in species where both are needed to raise the young). So the female is designed with some internal calendar (perhaps triggered by the length of the day), and a series of signals and behaviors (alluring pheromones plus enticing postures, say). In the season of love, on cue, as if activated by some Cartesian clockwork, both sexes become mad with passion.

If mating is to occur in the spring, then the rivalry of males for the attentions of females should also peak in the spring. If the lives of deer depend in part on their speed and their ability to fight back when cornered by predators, then intraspecific tests of strength, speed, stamina, and strategy among stags are to the benefit of the genes of the victors as well as to the deer clan. This is ritualized combat, almost never to the death. The point of the exercise becomes instantly clear as the doe gives herself to the winner. A multitude of such dramas over many generations helps deer keep pace with hereditary improvements in, for example, the hunting skills of wolves.

In many predatory species, animals hunt together. Prey is flushed into ambush, or is exhausted by repeated feinting. Stragglers, usually the weak, the young, and the old, can be isolated. The predators may adopt a relay system, Group One performing feints only, and Group Two loping along to pick up the attack when Group One is exhausted. Cooperation makes hunting much more efficient, and the predators may now bring down animals much larger than they are.

Members of hunting packs have a kind of ethic: Whatever rivalries they bear are put aside during the hunt. For them too, “politics stops at the water’s edge.” There’s a different set of social rules within the group than without. But it’s an easy step from attacking animals of other species to attacking strangers of the same species. This is true of dogs and lions, which hunt in packs, and of ants and penguins, which do not. They behave as if special loyalty is owed to their group only; suspicion and hostility are due all others, even though they are fellow members of the same species. And this is not restricted to hunting packs. It’s a fact of life among most sociable birds and mammals.

Ethnocentrism is the belief that our group (whichever it happens to be) is at the focus of everything good and true, the center of the social universe. We do things the way they were meant to be done. Xenophobia is the fear and hatred of strangers. Their behavior is wrong-headed or weird or abominable. They don’t have the same respect for life that we do. And anyway they’re out to get us. “Us against them,” again. Ethnocentrism and xenophobia are extremely common among birds and mammals, although they do not constitute an invariable rule: Flocks of migrating birds, for example, are pretty much open to all comers of the same species.

If we’re confronted by some stranger who means harm to both of us, then we’re motivated to put aside whatever differences lie between us and together deal with the common enemy. Our chance—as individuals and as a group—of surviving an attack is greatly improved if we make common cause with our fellows. The existence of common enemies can work as a powerful unifying force. Common enemies make the social machinery purr. Those groups that incline to xenophobic paranoia might gain a cohesive advantage over groups that are initially more realistic and carefree. If you’ve exaggerated the threat, at least you’ve reduced internal tensions in your group; and if the external threat is more serious than you’ve privately estimated, your preparedness is higher. As long as the social costs stay within reasonable bounds, it may become a successful survival strategy. So there’s a kind of contagion about xenophobia.

Even among animals that as adults have few natural enemies—dolphins, say, or wolves—the young are vulnerable. Special steps must be taken to protect them. Adult dolphins keep very close to the young. Wolf cubs are cautious and fearful in their first few months of life. Many nestlings beg for food with visual, not auditory, cues so as not to attract the unwelcome attention of predators. These measures are useful in dealing with both interspecific and intraspecific violence: Because so many group-living animals attack members of other groups who stray into their territory, the young have good reason to be wary of strangers.

Among the wildebeests, an African antelope hunted by many predators, the calf shakily stands within a few minutes after birth. Five minutes later it can follow its mother, and in twenty-four hours it can keep up with the herd. Wildebeests grow up fast. In other animals, of which humans are the most striking example, the young are born utterly helpless. If abandoned by their parents, they would perish in a few days, predators aside. A wildebeest mother need make few concessions to her young, apart from permitting them to suckle. Human mothers (and robin, wolf, and monkey mothers, among many others) must adopt a complex behavioral repertoire in order for there to be a next generation. In higher mammals, these special activities may last years or even decades—until the youngster is nearly fully grown. For so major an investment to be made, there must be a comparably major benefit. The long childhood of the higher mammals is connected with their larger brains and with the necessity that the young be taught. This frees the youngsters from the comparative inflexibility of having preprogrammed genetic knowledge only.

In many animals there’s a period early in life during which profound and irreversible learning occurs, a time, for example, when a duckling will follow anything nearby that moves as if it were Mom—even if it’s a bearded pioneer in animal behavior. This is called imprinting. Some imprinting goes on even before birth. Ducklings, before they hatch, memorize the voice of whoever is incubating them, and respond (by peeps from inside the egg). If it’s a human who talks to the egg during incubation, that’s the voice the duckling responds to after it’s hatched. Imprinting may involve learning a call, a song, an odor, a shape, or a food preference, and is accompanied by deep emotional bonding. The information is implanted in the memory for a lifetime.

These sounds, smells, and sights are associated with food, warmth, love, and safety in an often-hostile world. Lambs, chicks, and goslings must reliably recognize and follow their perambulatory mothers; failure to do so is punishable by death. It’s no wonder imprinting lasts for life. The predisposition to be imprinted is programmed in the DNA and subject to very strict constraints (in some cases imprinting can occur only in a specific one- or two-day period over an entire lifetime). But the specific information that is so indelibly etched is conditioned by environment and experience, and differs from animal to animal. In this way the youngster can learn, generally from its parents, wisdom too recent to have been inscribed in the latest edition of the nucleic acids.

An unfocused inclination towards ethnocentrism and xenophobia can be particularized as needed in each generation. The groups to which loyalty is owed and the ones deserving special hatred and contempt may change from generation to generation. Imprinting is a means for fitting general proclivities to practical politics, and is a form of education. The machinery stands ready for those who know how to use it. The young animals have a nearly eidetic memory. But they have no critical faculties. They’ll believe anything—whatever they’re taught. As the example of the parade of ducklings waddling adoringly after the ethologist reminds us, imprinting might lead, in unscrupulous higher animals, to misuse. The young are so ready to learn who to love and who to hate.

If the nipples and vaginas of nursing rats (“suckling dams,” the scientists call them) are regularly swabbed with the scent of lemon, the male pups, when grown, are preferentially attracted to lemon-scented females—foreswearing the naturally aromatic, accessible, and nubile alternatives.15 This odor imprinting suggests how powerfully early experiences can affect later sexual preference and performance. It’s something like the line in the song that goes, “I want a girl just like the girl that married dear old Dad.” But humans are not rats.

With long childhoods and efficient imprinting, animals can make wholesale changes in their behavior to adapt to a changing environment—taking only a few lifetimes instead of a geological age. In turn, this bonds mothers and offspring together still more closely. It creates something akin to love. It also means that different communities of the same species may have different patterns of behavior that are passed down the generations—even if the groups are, genetically, essentially identical. The strategy of long childhoods and early learning introduces a new element: culture.

——


Human life begins in a race of one against hundreds of millions The stampeding sperm cells are competitive from the start. But the whole point of the-rivalry is cooperation of the most intimate sort. The two cells wholly merge. They combine their genetic material. Two very different beings become one. The act of making a human being involves an almost bizarre mix of opposites—desperate competition against all odds, and cooperation so perfect that the partners’ separate identities vanish. It would be inconsistent for beings who arise out of intense rivalry and begin in perfect cooperation to decry either.

“In the ways of Nature,” said Marcus Aurelius, “there is no evil to be found”16 Animals are aggressive not because they are savage, or bestial, or evil—those are words with very little explanatory power—but because such behavior provides food and defense against predators, because it spaces out the population and avoids overcrowding, because it has adaptive value. Aggression is a survival strategy, evolved to serve life. It coexists, especially in the primates, with compassion, altruism, heroism, and tender, self-sacrificing love for the young. These are also survival strategies. Eliminating aggression would be a foolish as well as an unachievable goal—it’s built too deeply into us. The evolutionary process has worked to achieve the right level of aggression—not too much, not too little—and the right inhibitors and disinhibitors.

We emerge out of a turbulent mix of contradictory inclinations. It should be no surprise that in our psychology and our politics a similar tension of opposites should prevail.


* A very nice test of these ideas are the observations by the animal behavior expert Stephen Emlen He thought to examine jacanas, birds in which the usual sex roles are reversed: Males do all the parenting and the females compete vigorously for something like a harem of males Those females who don’t possess a harem don’t reproduce, so the dominant females are often challenged by lower-ranking females When a takeover attempt succeeds, the incoming female routinely destroys the eggs and kills the chicks She then sexually solicits the males, who now have no young to distract them—and so are able to attend to propagating the genetic sequences of the incoming female The genetic strategy of infanticide is situational, not gender-based* Another aspect of the gestural vocabulary of appeasement is infantile behavior in adults, including begging. It’s a little like human lovers using baby talk and calling each other “baby.” They’re applying a lexicon established in infancy to another purpose




Chapter 11




DOMINANCE AND SUBMISSION


When we no longer look at an organic being as


a savage looks at a ship, as something wholly


beyond his comprehension; when we regard


every production of nature as one which has


had a long history; when we contemplate every


complex structure and instinct as the summing


up of many contrivances, each useful to the


possessor, in the same way as any great


mechanical invention is the summing up of the


labour, the experience, the reason, and even


the blunders of numerous workmen; when we


thus view each organic being, how far more


interesting—I speak from experience—does the


study of natural history become!


CHARLES DARWIN,


The Origin of Species1





Order. Hierarchy. Discipline.


BENITO MUSSOLINI,


proposed national slogan2


The two pit vipers slither toward one another in silence, forked tongues flickering. Slowly they entwine in a languorous embrace. They raise themselves higher and higher off the ground. The glistening coils ebb and flow. Like some macroscopic echo of their underlying microscopic reality, they form a double helix.

Once, observers concluded that this is a reptilian courtship dance. They neglected to capture the snakes, though, and determine their sexes. When this is done, both snakes turn out to be male So what are they doing? Since homosexual embraces are known throughout the animal kingdom, it still might be a courtship dance—except that it usually ends with one snake toppling the other to the ground, no overt sexual acts having transpired. Instead, this hypnotizing serpentine ritual seems to be a competition, like arm wrestling, played by strict rules. No combatant has ever been bitten or even injured, so far as we know. When the duel ends, whoever has been forced over accepts defeat and slithers away.

Is this contest about access to females? Sometimes there’s no female in evidence, urging her champion on, or available as a reward for the victor. At the least, this is a struggle over hierarchy, over who’s the top viper—which does not exclude the possibility that the encounter is homosexual as well: Male competition for dominance expressed in homosexual metaphor is a theme widespread among the animals.

Losing the struggle is apparently a blow to the snake’s self-confidence. He seems morose and demoralized, unable many days later to defend himself against even weakling rivals. Here’s one mechanism by which struggles for dominance later convert into mating success: A female viper, on meeting a lone male, will mimic male behavior and raise herself up as if preparing for this sportive combat. If, still despondent from his last defeat, he does not with sufficient vigor rise to the occasion, she looks elsewhere for a mate.3 Almost without exception, the females manage to mate with the winners.4

Among pit vipers,5 a male will take one or more sexually receptive females under his “protection” and do what he can to discourage the approach of other males. He will defend or compete for specific territories, especially those that contain resources important for the next generation of vipers. The most celebrated American pit viper, the prairie rattlesnake, does not mate as it comes out of hibernation in the spring, but waits until the late summer when a male must make a considerable effort to track down a female.

In contrast, the garter snakes of Manitoba hibernate in enormous dens of perhaps ten thousand individuals, the proverbial snake pit. In springtime, the females are sexually receptive as they emerge, one at a time, from the den. And a good thing, too: Waiting impatiently is a gang of several thousand males, who pounce on each female as she exits, forming a writhing, orgiastic, but largely infecund “mating ball.” Competition among the males is fierce, both pre- and post-coitus; after mating, the victor will insert a vaginal plug so no rivals can succeed if he has failed to impregnate the object of his affections. Even among snakes there is a core of basic behavior—including dominance, territoriality, and sexual jealousy—that humans have no trouble recognizing.

——


With very few exceptions, animal societies are not democracies. Some are absolute monarchies, some fluid oligarchies, some—especially on the female side—hereditary aristocracies. Dominance hierarchies exist in almost all, except for the most solitary, species of birds and mammals. There’s a rank order based mainly on strength, size, coordination, courage, bellicosity, social intelligence. Sometimes you can predict, just by looking, who’s dominant: the stag with the most points on his antlers, say, or that large, spectacularly well-muscled gorilla with the silver back. In other cases it’s someone you wouldn’t have guessed, someone without imposing physical stature, someone whose leadership qualities may be apparent to the animals you’re observing but not to you.

The dominant animal—as determined in ritualized or occasionally in earnest combat—is called “alpha” after the first letter of the Greek alphabet. After alpha comes beta, then gamma, delta, zeta, eta … and so on down to omega, the last letter of the Greek alphabet. Most often, alpha lords it over beta, who makes appropriate indications of submission; beta over gamma, gamma over delta, and so on down the hierarchy.* The alpha male might exhibit dominance behavior in the male hierarchy 100% of the time, the omega male or males 0% of the time, with those in between showing intermediate frequencies

Apart from the dubious intrinsic satisfaction of intimidating others, high rank often carries with it certain practical benefits—the privilege of dining first and from the choicest morsels, say, or the right to have sex with whomever strikes your fancy. The most passionate enthusiasts of dominance hierarchies are almost always the males, although loosely parallel female dominance hierarchies occur in many species Males generally dominate all females and all juveniles. Among the comparatively rare species in which females sometimes dominate males are the vervet monkeys, the very same who keep their cool when overcrowded.

While privileged access to desirable females is not the invariable accompaniment of high rank, it is a frequent benefit In a population of mice, the top third of the hierarchy was responsible for 92% of the inseminations. In a study of elephant seals, the bulls in the top 6% of the dominance hierarchy impregnated 88% of the cows.6 High-ranking males often work hard to prevent lower-ranking males from inseminating the females. Females sometimes act to incite rivalry among the males.7 If the dominant males are going to father almost all the children, then clearly there’s a major selective advantage to being a dominant male. Whatever inherited qualities predispose to accomplishing, maintaining, and enjoying dominance will swiftly be established throughout the population—or at least among the males. Social and individual constitutions will be reconfigured by evolution to this end. Indeed, there seem to be parts of the brain in charge of dominance behavior.8

Promotion in rank does not usually occur because of community social work or fighting off invaders. Promotion comes mainly from combat within the group—mainly ritualized, sometimes real. Darwin clearly understood how natural selection might bring this about:The law of battle for the possession of the female appears to prevail throughout the whole great class of mammals. Most naturalists will admit that the greater size, strength, courage, and pugnacity of the male, his special weapons of offence, as well as his special means of defence, have been acquired or modified through that form of selection which I have called sexual. This does not depend on any superiority in the general struggle for life, but on certain individuals of one sex, generally the males, being successful in conquering other males, and leaving a larger number of offspring to inherit their superiority than do the less successful males.9


If you’re a second lieutenant in the hierarchy and wish to be promoted, you challenge your first lieutenant; he would challenge his captain; he his major; and so on, up the ladder. In this respect at least, animal dominance hierarchies and human military hierarchies differ. Perhaps certain dog-eat-dog corporate hierarchies provide a better parallel. In the case of a successful challenge, the two animals sometimes exchange status, silver bars for gold. Animals weakened by disease, injury, or age are generally broken to the ranks.

“This town ain’t big enough for the both of us” isn’t the way dominance hierarchies usually work. Faced with a testy alpha male, you have another option besides fight or flight. You can submit. Almost everybody does. Subordinate males ingratiate themselves to those at the top of the hierarchy through incessant bowing and scraping. From their proximity to power those next in rank tend to gain access to food and to females, the leavings of the alphas. Sometimes dominant males are so busy with their police functions that those lower in the hierarchy can arrange sexual trysts that never would have been permitted had the alphas been less preoccupied. Surreptitious fertilization of females when the alpha male isn’t looking is called “kleptogamy.” “Stolen kisses” has something of the same flavor. So being alpha is only one strategy for males to continue their lines. Being beta or gamma with an inclination for kleptogamy is also a strategy. There are others.

An unambiguous, well-defined dominance hierarchy minimizes violence. There’s plenty of threat, intimidation, and ritual submission, but not much bodily harm. Violence does occur when the rank order is uncertain or is in a state of flux. When young males attempt to establish their place in the hierarchy, or when there’s a struggle at the top for alpha status, then there can be serious injuries, even death by combat. But if you don’t mind constantly subordinating yourself to those of superior rank, dominance hierarchies provide a peaceful and ritualized environment with few surprises. Perhaps this is part of the appeal for those humans drawn to the religious, academic, political, police, and corporate hierarchies, and the military establishment in peacetime. Whatever inconveniences hierarchy may impose are offset by the resulting social stability. The price may be paid in anxiety—anxiety about offending those of higher rank, being perceived as insufficiently deferential, forgetting yourself, committing lèse-majesté.

In maintaining the dominance hierarchy, all conflicts (chiefly ritual or symbolic combat) are between animals who know each other well. But xenophobic intraspecific aggression is different, occurring between animals with no perceived bonds, relationships, or even familiarity. It’s an encounter with strange-smelling aliens, and the circumstance most likely to lead to casualties and deaths.

When an unfamiliar mouse arrives, rats drop what they’re doing and attack it—dominant rats attacking the intruder’s back and frequently mounting it in the process, while subordinate rats attack the intruder’s flanks and rarely mount it. Each in his own way.10 Among mice living in small groups, those at the top of the hierarchy tend to be most active in scuffling, intimidating, and fighting, in reacting to novelty, and in fathering baby mice. They also have sleeker coats than the subordinate males. But when it comes to fighting mice of another group,11 suddenly democratic forms come into play and the subordinates fight side-by-side with the alphas.*

The simplest geometry of a dominance hierarchy is linear or straight-line. This is what we’ve been describing. The private defers to the corporal, the corporal to the sergeant (and if you look more closely, there are various hyperfine grades of privates, corporals, and sergeants), the sergeant to the second lieutenant, and so on, up through first lieutenant, captain, major, lieutenant colonel, colonel, brigadier general, major general, lieutenant general, plain old general, and general of the army or field marshal. The military establishments of different nations have different names for the various ranks, but the basic idea is the same: Everyone knows his rank. A currency of deference is offered by subordinate to superior. Homage is paid.

Linear hierarchies are a mode of social organization readily observable in domestic fowl, which is where the phrase “pecking order” originates. It’s especially clear-cut among the hens. (In mammals the pecking order is often the chief fact of male social life.) Again, the alpha hen pecks beta and everybody lower; beta pecks gamma and everybody lower; and so on down the hierarchy to poor omega, who has no one at all to peck. The high-ranking males try to sexually monopolize the hens, but sometimes they fail. Cocks dominate hens except on rare occasions; the word “henpecked” refers to the exceptions and comes from everyday observation of barnyard life.

With large populations a linear rank order is rare; instead, little triangular loops break out in which delta dominates epsilon, epsilon dominates zeta, but zeta in addition to dominating eta also dominates delta, or maybe even someone higher up the hierarchy.12 This leads to a social complexity that may be opposed by die-hard conservative chickens.

How does the dominance hierarchy get established? When two chickens are introduced to each other, there is usually a brief squabble—involving much clucking, squawking, pecking, and feathers flying. Or else one chicken takes a good look at the other and submits without a fight, as is usually the case when an immature chicken is confronted by a healthy adult. Among vigorous hens, the winner is the better fighter, or the better bluffer. A home-court advantage is reported: A hen is more likely to win the fight in her own yard than in her adversary’s. Aggressiveness, bravery, and strength play their roles. After a single instance of dominance combat, the relationship between the two hens is often frozen; the higher-rank has the right to peck the lower-rank without fear of retribution. Flocks in which high-ranking hens are regularly removed and replaced by total strangers fight more, eat less, lose weight, and lay fewer eggs. In the long view, the pecking order is in the interest of the chickens.13

“Playing chicken” is an American male adolescent game of 1950s vintage in which each threatens the other to see who will flinch first. The most familiar example involves automobiles speeding directly toward one another; he who swerves first may gain his life (and, incidentally, save that of his rival) but lose his status. Calling it “playing chicken” recognizes its deep evolutionary origins. Being chicken, in the same youth culture, means being fearful of performing a risky or heroic action. Again, the behavior of subordinates in the barnyard dominance hierarchy is evoked; again, the choice of words betrays if not real knowledge at least a suspicion of the animal roots of the practice.

Another way in which our awareness of animal dominance hierarchies has insinuated itself into the language and proves useful in describing our own behavior is the use of the phrases “top dog” for the alpha male and “underdog” for everyone else. When we say we’re for the underdog in sports or politics or economics, we’re revealing an awareness of dominance hierarchies, their injustice and their shifting fortunes.

There are monarchical social systems in which everyone is dominated by the alpha male or the few highest-ranking males, and hardly any aggression occurs in the rest of the group. The dominant male spends a considerable amount of his time calming outraged subordinates and adjudicating disputes. Sometimes justice is a little rough, but often merely a bark or grimace will suffice. In such systems especially, dominance hierarchies carry with them social stability. The males of many species have evolved potent weaponry. Life would be a lot more dangerous if every time two piranha males, or two lions, or two stags, or two elephant bulls had a difference of opinion, it was a fight to the death. The dominance hierarchy—with relative status fixed for considerable periods of time, and the institutionalization of ritualized rather than real combat in settling serious disputes—is a key survival mechanism. Not only is there a genetic advantage for the dominant male, but also for everyone else. Pax dominatoris. Even if you have to take a lot of abuse, even if you sometimes resent the brass, it’s safe, maybe even comfortable, in such a system—where everyone knows his place.

So what kind of selection is this? Is it simple individual selection for the alpha male, with the benefit for other males being only incidental? Is it kin selection, because the lower-ranking males are not-too-distant relatives of the alpha? Is it group selection, because such a group, structured and stabilized by a dominance hierarchy, is more likely to survive than one in which combat to the death is the norm? Are these categories separable and distinct?

The alpha might be of a mind to attack an offending inferior, but if the latter makes the species’ characteristic submission gestures, the former feels obliged to spare him. They have not sat down and agreed on a moral code, no tablets have been carried down from the mountain, but the postural and gestural inhibitions to violence work very much like a moral code.

One of the most spectacular examples of dominance behavior in groups—known among animals as different as birds, antelopes, and (perhaps) midges—is called the lek:[L]eks are tournaments, held before and during the breeding season, day after day, when the same group of males meet at a traditional place and take up the same individual positions on an arena, each occupying and defending a small territory or court. Intermittently or continuously they spar with their neighbours one at a time, or display magnificent plumage, or vocal powers, or bizarre gymnastics … Though they have territories, yet they have a hierarchy with the top-ranking males typically placed in the middle and ungraded lesser aspirants ranged outside. Females come to these arenas in due course to be fertilized, and normally they make their way through to one or other of the dominants in the centre.14


Perhaps spring break at Ft. Lauderdale or Daytona Beach is one of the more conspicuously lekish human institutions.

Among reptiles, amphibians, and even crustaceans, dominance behavior is common.15 The varanids (such as the komodo dragon) are very good at ritualized and stereotyped intimidation displays. They rattle or lash their tails, rear up on their hind legs, inflate their throats, and, if their rival has not yet submitted, attempt to wrestle him to the ground. In crocodiles, dominance is established by slapping the head into the water, roaring, lunging, chasing, and biting, pretend or real. When interrupted in his mating embrace, a male frog croaks; the deeper his croak, the greater his implied size when disengaged, and the more diffident is the would-be intruder. A toothless, brightly colored Central American frog, genus Dendrobates, intimidates intruders by performing a vigorous sequence of push-ups. But among the skinks, in which aggression is released seasonally when the heads of the males turn bright red, the virtues of intimidation by bluff are often lost sight of, and the two rivals tear into each other without so much as a preliminary throat swelling. When hermit crabs introduce themselves, they devote a few seconds to taking each other’s measure—by stroking one another with their antennae; the smaller then promptly submits to the larger.16 Stalk-eyed flies do the same; the more dominant individuals are the ones with the more widely separated eyes.

It’s rare that any male starts out as an alpha. Generally you have to work your way up through the ranks. But in the intervals between your challenges it would be a mistake to be too disruptive. Even for the very ambitious a talent for subordination and submission is needed. Also, it’s hard to predict who will achieve high-ranking status. Sometimes greatness is thrust upon unsuspecting animals by the course of events. Accordingly, everyone needs to be able to rise to the occasion. If you’re in a linear hierarchy, you must know how to dominate the animals below you and submit to those above. An inclination for both dominance and submission must beat within the same breast. Complex challenges make for complex animals.

——


Nothing we’ve said so far indicates anything about female preference. What if she finds the alpha male arrogant, boorish, taking too much for granted? Or just plain ugly? Does she have the right to refuse? At least among hamsters, this is not an option.

Here’s an experiment17 done on Syrian hamsters by the psychologist Patricia Brown and her colleagues: To begin, males, matched for size and body weight, were allowed to interact with one another in pairs to establish dominance. Chasing and biting were among the behaviors counted as dominant; defensive postures, evasions, raised tails, and full cowering submission were counted as subordinate traits. The dominants accounted for over ten times more aggressive acts than an equal number of subordinate animals; the subordinate animals tallied ten times more submissive acts than those judged dominant. It never took more than an hour for a pair of hamsters to decide who was dominant and who was subordinate.

Now although these males knew how to fight, they’d never had a sexual experience. Each of them was made to wear a little leather harness attached to a tether, which, like a dog’s leash, limited how far he could roam. Next, an ovulating female was released; she could have access to the tethered males, but beyond a certain point their leashes would prevent them from following her or offering unwelcome attentions. Whatever sexual contact might be in the offing would be on her terms.

We imagine her, steely-eyed, slowly looking the males over head to tail in their kinky leather outfits. Because the earlier dominance conflict was largely ritual, there were no injuries to betray which was the subordinate animal. Each male was in its own partitioned area, so they could not see one another and betray to the female their relative status through gestures of dominance or submission. Would she, despite the absence of signs apparent to the human observers, select the dominant male? Or would she find some other trait more attractive? The females were not hesitant or demure. In less than five minutes, every one of them presented herself for copulation to one of the males. In every case it was the dominant male. Prior familiarity was not required. Somehow she knew. There were no questions asked about his education, family, financial prospects, or the gentleness of his disposition. Every female was eager for sex with the dominant male.

How could the female know? The answer seems to be that she could smell dominance. There is literally a chemistry between them, the odor of power. The dominant males give off some effluvium, some pheromone that subordinate males do not.18

“I’m a celebrity. That’s what celebrities do,” offered one-time heavyweight boxing champion Mike Tyson in explaining his scattershot propositioning of virtually every contestant at a beauty pageant. Former U.S. Secretary of State Henry Kissinger, not known for his looks, explained a beautiful actress’s attraction to him in these words: “Power is the greatest aphrodisiac.”

Dominant males preferentially copulate with attractive females. The females are as accommodating as they can be. They crouch down, they raise their hindquarters, they lift their tails out of the way. (We’re back to hamsters.) In Brown’s rodents-in-motorcycle-jackets experiment, during the first half hour of mating the number of “intromissions” by dominant males averaged 40; those subordinate males able to score at all (usually after the dominants were done) averaged a measly 1.6 for the half hour.

Now suppose you grow up in a society in which such behavior is the community standard. Wouldn’t you tend to conclude that the animal who mounts and who makes repeated pelvic thrusts is the dominant partner, while the animal who crouches, who is receptive and passive, is subordinate in rank? Would it be surprising if this powerful symbol of dominance and submission were generalized in the gestural and postural vocabulary of the status-obsessed males?

Before the invention of language, animals need clear symbols to communicate with one another. There’s a well-developed non-verbal language, which we’ve already described, including “My belly’s up and I surrender” and “I could bite you but I won’t, so let’s be friends.” It would be very natural if everyday reminders of status in the rank hierarchy were established by brief ceremonial mountings of males by males. He who mounts is dominant; he who is mounted is subordinate. No “intromission” is required. Such symbolic language is in fact widespread, and we will discuss it in greater detail in later chapters. It may have little or no overt sexual content.

Under natural conditions, ordinary Norway rats—the same common variety whose social structure collapsed in Calhoun’s overcrowding experiments—arrange themselves into social hierarchies. A dominant might approach a submissive animal, sniff and lick its anogenital area, and mount it from the rear, holding on with the forepaws. The submissive animal might elevate its hindquarters so as to indicate its eagerness to be mounted. Male aggression in maintaining the dominance hierarchy includes banging flanks, rolling over and kicking, pinning the opponent with the forepaws, and boxing—the two animals actually stand toe-to-toe and let loose with left jabs and right uppercuts. Under normal conditions it’s rare that anyone is injured.

Even among lobsters the aggressive posture is to stand upright—indeed, on their toes (or at least the tips of their claws). The submissive posture is flat on the ground, legs somewhat akimbo. The idea is to show that you can’t (quickly) do any harm, even if you want to. Many gestures in a similar spirit can be found among humans. Police confronting possibly armed suspects will order them to raise their hands (so it’s clear they’re weaponless); or clasp their hands behind their necks (ditto); or lean at a high inclination angle against a wall (so their hands must support them); or lie prone. Submissive words are well and good (“I didn’t mean nothin’, honest”), but a police officer putting his or her life on the line requires a firmer postural guarantee.

In almost all higher mammals copulation occurs with the male entering the female’s vagina from behind. The female crouches down to assist the male in mounting her. She may make special motions to aid his entry, and those motions, like the bump and grind, become part of the symbolic language of enticement. The reason for the crouch is partly to present a favorable geometry for entry, but it also indicates that she has no intention of going anywhere. She’s not about to run away. Something similar can be seen in many other species. A male beetle come a-courting taps on the female’s carapace—in different beetle species, drumming with his feet, his antennae, his mouthparts, or his genitals—and she is instantly immobilized.19 The strange attractiveness to men of grotesquely deformed small feet (in China for nearly a millennium), and of very high heels (throughout the modern West), as well as traditional, constraining women’s clothing20 and the fetish of female helplessness in general, may be a human manifestation of the same symbolism.

In many species the alpha male systematically threatens any other male attempting to mate with any female in the group, especially when conception is possible. Because of clandestine impregnations by subordinate males—kleptogamy—in which the females are often willing partners, the alpha does not always succeed; but he’s highly motivated to try. This is true within female dominance hierarchies as well. In domestic fowl, for example, the alpha female tends to attack any female that so much as walks up to an adult male during the breeding season. In gelada baboons, in which there is a female dominance hierarchy, high-ranking females do not, on average, mate more frequently during ovulation than do the lower-ranking females; but the lower-ranking females rarely give birth. Something about their inferior status diminishes their fertility. Perhaps they are advertising ovulation when in fact no egg is released, or maybe they have many spontaneous abortions. But whatever it is, their low status prevents them from having babies. In marmosets, subordinate females tend to suppress their ovulations, but when they are freed from the female dominance hierarchy, they quickly become pregnant.21 Thus, genes contributing to high status in the female hierarchy—large stature, say, or superior social skills—get preferentially passed on to the next generation. This tends to stabilize a hereditary aristocracy.

In cattle and many other animals, the alpha male may try to gather around him a harem of females and chase away the other males, but his success is often limited. When the breeding time has passed, the males return to their solitary ways and the females (and young) resume their own social grouping. Among deer this is called a hind group and entails its own dominance hierarchy. Commonly, the leader of such communities is determined not by bluff, threat, or fighting ability, but by age: The oldest fertile female leads. (The same convention is adopted among all-female herds of African elephants; even when composed of hundreds of elephants, the social structure is extremely stable.) These groups seem to be organized around protection. When attacked, they form a diamond- or spindle-shaped pattern, with the alpha female in front and the beta bringing up the rear. If the pursuers are gaining, the beta female may valorously stop short and engage the leading predator. As the rest of the group makes its escape, the alpha and beta may then exchange sentry duty.

In skirmishes the advantages of the dominance hierarchy are clear. Even female mammals who evince little enthusiasm for individual dominance nevertheless arrange themselves into battle hierarchies in times of trouble. So dominance hierarchies have at least two functions, extremely useful both for individuals and for the group: They reduce dangerous and divisive fighting within the group (promoting what we might call political stability); and they are optimized for inter-group and interspecies conflict (providing what we might call military preparedness).

A third purported advantage of dominance hierarchies is that they preferentially propagate the genes of the alphas, those who are physically or behaviorally fit. We might imagine a common conditional strategy for everyone in the group that would go something like: “If I’m big and strong, I intimidate; if I’m small and weak, I retreat.” This benefits everyone one way or another, and the sole focus is on the “I.”

Being human, we naturally feel some whiff of resentment when we imagine ourselves dropped into such a dominance hierarchy with its craven submissiveness and manifest cruelties. Being human, we might also imagine the pleasures of a well-run social machine in which everybody knows his place, in which nobody gets out of line and causes trouble, in which deference and respect to superiors is routinely shown. Depending on whether we come from a more democratic or a more authoritarian upbringing, schooling, or society, we might feel that the benefits of the dominance hierarchy outweigh any affront to freedom and dignity, or vice versa. But this discussion isn’t yet about us. Humans are not red deer or hamsters or hamadryas baboons. For these species the cost-benefit analysis has been made. For them, law-and-order is the higher good. That there are innate individual rights and liberties of hamsters, needing institutional protection, is not a self-evident truth.

——


To play the hierarchy game, at the very least you must be able to remember who’s who, to recognize rank, and to make the appropriate responses, dominant or submissive as circumstances dictate. The ranks are not fixed in time, so you must be able to reassess and revise facts of central importance. Dominance hierarchies bring benefits, but require thinking and flexibility. It’s not enough to have inherited nucleic acid instructions on how to threaten and how to submit. You must be able to apply those behaviors appropriately to a changing array of acquaintances, allies, rivals, lovers—whose dominance status is situational and whose identity and current circumstances cannot possibly be encoded in the nucleic acids. As is also true for hunting and escape strategies or learning from parents, hierarchies require brains. Nevertheless, the instructions in the genes are often vastly more in control than whatever wisdom resides in the brain.

Early on, animals may not have been very adept at distinguishing individuals, contenting themselves with “If he gives off my favorite sex attractant, he’s my guy.” In interaction with predator and prey, or in the sexual adventuring of males who are not obliged to care for the offspring, there’s no high premium on the niceties of individual recognition. Then you can get away with “They all smell the same to me” or “They’re all the same in the dark.” Then you can stereotype and there are few adaptive penalties you must pay. But as evolutionary time passes, finer distinctions must be made. It might be useful to know who the father of your child is so you can encourage him to play a role in raising and protecting it. It might be useful to know the exact position of all the other males in the dominance hierarchy if you wish to avoid daily conflicts about rank, or if you wish to advance up the ladder.

One of the many surprises in modern primate research is how readily the human observer—even if wholly insensitive to olfactory cues—can distinguish and recognize all the baboons in the troop, all the chimps in the band. If you spend a little time with them, they no longer all “look alike.” It takes some motivation and a little thought, but it’s well within our powers. Without such individual recognition, the greater part of the social life of higher animals, as of humans, remains hidden from us. With humans—because of language, dress, and behavioral eccentricities—individual recognition is much easier. Still, the temptation to divide humans and other species into a small number of stereotyped categories, rather than recognizing differences and judging individuals one at a time, remains deep within us.

Racism, sexism, and a toxic mix of xenophobias still powerfully influence action and inaction. But one of the proudest achievements of our own age is the developing global consensus—despite many false starts—that we’re at last ready to leave behind this vestige of long ago. Many ancient voices speak within us. We are capable of muting some, once they no longer serve our best interests, and amplifying others as our need for them increases. This is cause for hope.

As for the larger issue of dominance and submission, the jury is still out. True, all but the pomp and costume of monarchy have, in the last few centuries, been swept off the world stage, and attempts at democracy seem fitfully to be breaking out planetwide. But the call of the alpha male and the compliant assent of the omegas remain the daily litany of human social and political organization.


ON IMPERMANENCE


As for Man, his days are as grass; as a flower of the field, so he flourisheth.

For the wind passeth over it, and it is gone; and the place thereof shall know it no more.


Psalm 103, verses 15,16, King James translation



* Alpha also dominates gamma and those below gamma; beta dominates delta and those below delta, and so on Since more animals submit than dominate, it might with greater justice be called a submission hierarchy than a dominance hierarchy But we humans are transfixed by dominance and often, at least in the West and setting religion aside, a little repelled by submission Vast libraries are written on “leadership” and virtually nothing on “followership”* The very recent history of human warfare provides a contrast: The alphas—generally old men—sequester themselves in safety, often where the young women are, and dispatch the subordinates—generally young men—out to fight and die. In no other species have alpha males gotten away with such cushy arrangements for themselves. It does require at least implicit cooperation between the alphas of rival groups, but this can often be arranged Apart from the social insects, no other species has been clever enough to invent war It is an institution optimally configured to benefit the alphas




Chapter 12




THE RAPE OF CAENIS



Not the immortal gods can flee,

nor the men who live only a day.

Who has you within him


is mad.


SOPHOCLES,


Antigone1






Over the Earth he flies


and the loud-echoing salt-sea.


He bewitches and maddens the heart


of the victim he swoops upon.


He bewitches the race of the mountain-huntin


lions and beasts of the sea,


and all the creatures that Earth feeds,


and the blazing sun sees—


and man, too—


over all you hold kingly power,


Love, you are the only ruler


over all these.


EURIPIDES,


Hippolytus2


One of the myths of ancient Greece tells of Caenis, “loveliest of the maids of Thessaly,” who, while walking alone on an isolated shore, was spied by Poseidon—god of the sea, elder brother of the king of the gods, and sometime rapist. Mad with lust, the god attacked her on the spot. Afterwards, he took pity, and asked what he might give in reparation. Manhood, was her answer. She wished to be transformed into a man—not just any kind of man, but one extravagantly male, a warrior and “invulnerable.” Then she would never again be subjected to such a humiliation. Poseidon agreed. The metamorphosis was completed. Caenis became Caeneus.

Time passed. Caeneus fathered a child. With his sharp and expertly wielded sword he killed many. But the swords and spears of his adversaries could not penetrate his body. The metaphor here is not hard to fathom. Eventually Caeneus became so full of himself that he scorned the gods. He erected his spear in the marketplace and made the people worship it and sacrifice to it. He insisted, on pain of death, that they worship no other gods. The symbolism is again lucid.

Extreme arrogance, of which this is a fair example, was called by the Greeks hubris. It was almost exclusively a male trait. Sooner or later it would attract the attention and then the retribution of the gods—especially toward those humans insufficiently deferential to the immortals. The gods craved submission. When news of Caeneus’s effrontery finally reached Zeus, whose desk was doubtless piled high with such casefiles, he ordered the centaurs—chimeras, half-man, half-horse—to execute his merciless judgment. Dutifully they attacked Caeneus, taunting him: “Do you not remember at what price you gained this false appearance of a man? … Leave wars to men.” But the centaurs lost six of their number to Caeneus’s swift sword. Their lances bounced off him “like a hailstone from a roof.” Disgraced at being “conquered by an enemy but half-man”—a hollow complaint, coming from a centaur—they resolved to smother him with timber, destroying vast stands of trees “to crush his stubborn life with forests for our missiles.” He had no special powers concerning breathing, and after a struggle they managed to subdue and then to suffocate him. When the time came to bury the body, they were amazed to find that Caeneus had reverted back to Caenis; the invincible warrior had become, once again, the vulnerable young woman.3

Perhaps poor Caenis had overdosed on the stuff that Poseidon used to effect the metamorphosis. There is a proper amount of whatever it is that makes one male, the ancient Greeks recognized, and too much or too little can get you into trouble.

——


The testicles of a sparrow are about a millimeter long and weigh about a milligram. (That’s one of the reasons you never hear that someone’s hung like a sparrow.) With testes intact, the scrappy birds enter into their mainly linear hierarchy, chase away other birds who invade their territory, and, if they’re high-ranking, make successful overtures to fertile females. But reach under those feathers, remove those two tiny organs, and, after the bird has recovered, all of these traits are lost, or nearly so. Aggressive birds become submissive, territorial birds become complacent about intruders, passionate birds lose interest in sex. Now inject a certain steroid molecule into the sparrow and it regains its plucky enthusiasm for sex, aggression, dominance, and territoriality.

Shortly after castration, male Japanese quails stop strutting, crowing, and copulating. They also fail to elicit the interest of female Japanese quails. Treat them with that same steroid and they’re back to strutting, crowing, and copulating, and the females find them irresistible once more. Castrate a young male fiddler crab and he will never develop his distinctive asymmetrical giant claw.

Humans have understood some of this for thousands of years. Captured warriors were castrated so they’d make no trouble. We still describe an ineffective leader as a “political eunuch.” Chieftains and emperors castrated men so they could guard the harems without succumbing to temptation (or at least—the compromise sometimes reached—without impregnating any of the residents); and so their loyalties to the leader would not be adulterated by family ties or other distracting affections and obligations. It is remarkable that almost exactly the same molecule should produce such fundamental changes in behavior in sparrows, quail, crabs, and humans.

The steroid molecule that works these transformations like some wizard’s potion is testosterone. Along with other, similar molecules, it’s called an androgen. It’s manufactured (from, of all things, cholesterol) mainly in the testicles,4 enters the bloodstream, and induces a complex set of behaviors that we recognize as characteristically male. Here too, the connection is acknowledged in the language, as in the expression “He’s got balls”—meaning he’s shown exemplary courage and independence, he’s not a coward or a sycophant.

In newly formed groups of male monkeys, the higher the rank in a forming dominance hierarchy, the more testosterone is found to be circulating in the blood. But when the hierarchy settles down to symbolic encounters, and betas are routinely submitting to alphas, the correlation vanishes. The more testosterone an animal has, the farther away he’s willing to roam to challenge and dominate potential rivals.6 With high testosterone levels there’s a cross-species tendency for dominance within the group to be extended to dominance over a piece of territory. The boss and the landlord become one.

In the brains of many animals are specific receptor sites to which the testosterone molecule and other sex hormones chemically bind, and which are in charge of hormone-induced behavior. There may be separate brain centers responsible for strutting, crowing, bullying, fighting, copulating, defending territory, and fitting into the dominance hierarchy; but each center has a button pushed by testosterone. The behavior is actuated once the testosterone migrates from the testicles through the blood to the brain. In the individual brain cells, the presence of testosterone activates otherwise untranscribed and ignored segments of the ACGT sequence, synthesizing a set of key enzymes. As with many hormones, testosterone is at the nexus of an array of positive and negative feedback loops that maintain the concentration of the molecule circulating in the blood.

Male animals don’t just endure, but seem to delight in, testosterone-mediated scuffles, intimidation, and combat. Mice will learn to run a complex maze when the only reward or reinforcement is the opportunity to have a tussle with another male. There are abundant similar examples in our species. Activities that are central to leaving many offspring tend to be entered into with enthusiasm. Sex itself is the most obvious example. Aggression is in the same category.

Even among animals with very short gestation periods, such as mice, the delay between conception and birth is too long for the animal to associate cause and effect. To leave it to mice to figure out the connection between copulation and the creation of the next generation is to condemn their genes to extinction. Instead there must be an absolutely overwhelming need for sex and—as a means of reinforcement—a delight in partaking of it. This is just the DNA creatively demonstrating its control in the most overt and clear-cut way.

A deal has been struck: The animal will forgo food, will conform to extreme postural indignities, will put its very life at risk so its strands of DNA can join up with the strands from some other animal of the same species. In exchange, there will be a few moments of sexual ecstasy, one of the currencies in which the DNA pays off the animal that carries it around and nurtures it. There are many other examples of DNA-mediated delight in activities tending toward adaptive fitness—including parental love for children, joy in exploration and discovery, courage, camaraderie, and altruism, as well as the standard array of testosterone-driven traits making bosses and landlords.

Hormones similar to testosterone play a central role in the development, of sexual organs and sexual behavior all the way down to the aquatic fungi. Steroids must have evolved very early to be so widely distributed today, perhaps going a fair way back to the invention of sex around a billion years ago.

This trans-species use of the same molecule for roughly the same sexual purpose has some bizarre consequences. For example, the chief sex pheromone in the pig is 5-alpha-androstenol—chemically similar to testosterone. It’s mixed in with the boar’s saliva (as testosterone is present in the spit of men). When a sow in heat smells this steroid on a slavering boar, she promptly adopts the come-hither mating posture. Oddly, truffles, the French culinary delight, produce exactly the same steroid and in a higher concentration than in boar spit. This seems to be why pigs are used by gastronomes to find and unearth truffles. (How strange it must seem to the sows, always falling in love with little black pieces of fungus, only to have them cruelly snatched away by humans.) Since truffles are fungi, in which steroids play key sexual roles, perhaps tormenting sows is just an accidental side-effect—or perhaps it serves the function of inciting pigs to dig so the spores are spread more widely and the Earth is covered with truffles.

Now in light of all this, what are we to make of the fact that 5-alpha-androstenol is also copiously produced in the underarm perspiration of men?7 Long ago—before institutionalized hygiene, before the present perfumed and deodorized age—might it have played a part in human and prehuman courtship and mating behavior? (The noses of women, we cannot help noting, are often at the same level as the armpits of men.*) Might this have something to do with the willingness of the rich to spend exorbitant sums on tiny pieces of a nearly tasteless cork-like substance?

A genetically male embryo deprived of testosterone and other androgens will emerge with what look very much like female genitals. Conversely, the genitalia of a genetically female embryo subjected to high levels of testosterone and other androgens will be masculinized: If smaller amounts of the steroid are present, perhaps she’s born with only a somewhat bigger clitoris; if larger amounts, her clitoris becomes a penis, and her labia majora fold over to become a scrotum. She may develop a normal-looking male penis and scrotum, although the scrotum will have no testicles within. (She’ll also have nonfunctioning ovaries.) Such girls as they grow up are found to prefer guns and cars to dolls and kitchen supplies, boy to girl playmates, and enjoy rough-housing and the outdoors; they may also find women sexually more attractive than men.8 (There’s no evidence for the converse—for example, that most tomboys have excessive amounts of androgens.)

The difference between male and female, not genetically but on so fundamental a matter as which set of external genitalia you are to have, depends on how much male steroid you encountered in the first few weeks after conception. Leave that bit of developing embryonic tissue alone and it will become a female. Suffuse it with a little testosterone-like hormone and it will become a male, † The tissue is spring-loaded to respond to the androgen (the word literally means “male maker”), which serves as a means of internal communication. There are buttons on the developing embryo that only androgens can push. Once they are pushed, substantial machinery, whose existence you might otherwise never have guessed, takes over and works mythic transformations.

Across widely different animal species, another class of sex hormones, the estrogens, curbs aggressiveness in females, and yet another, progesterone, increases the feminine inclination to protect and care for the young. (The words signify, respectively, something like estrus-maker and gestation-promoter.) Mother rats, as all mammals, are attentive to their offspring: They build and defend nests, nurse the pups, lick them clean, retrieve them when they wander away, and teach them. None of this behavior is evident in virgin females, though, who studiously ignore newborn pups, or even make some efforts to avoid them. But prolonged treatment with the female hormones progesterone and estradiol—bringing the hormone levels of virgins up to those typical of late pregnancy—results in the emergence of marked maternal behavior. Rats with high levels of estrogen are also less anxious and fearful and less likely to engage in conflict.10

These female hormones are produced mainly in the ovaries. But when we see a calm, competent, and loving mother, most of us are not driven to exclaim “Man, has she got ovaries!” The reason doubtless has something to do with the ready accessibility of testicles for accidental or experimental removal, dangling as they do in vulnerable external sacs*—quite differently situated than the ovaries, which are locked away for safekeeping within the vault of the body. But clearly ovaries must equally be counted as among the family jewels.

The female hormones control the estrus cycle—which culminates when the females are ovulating and, usually, broadcasting olfactory and visual cues that they’re available for mating. In many species this doesn’t happen often and doesn’t last long; cows, for example, are interested in sex for about six hours every three weeks. Cows don’t date much. “For most species,” writes Mary Midgley,11 “a brief mating season and a simple instinctive pattern makes of it a seasonal disturbance with a definite routine, comparable to Christmas shopping.” In a wide variety of mammals, from guinea pigs to small monkeys, mating outside of estrus is not only discouraged by the female, it’s also made physically impossible by an organic chastity belt: The vagina is sealed by a membrane or plug grown specially for the purpose, or—even more decisive—it’s fused shut.

In contrast, among most humans and some apes, sex is not only possible but is equally probable at virtually any phase of the cycle. Some humans monitor the cycle (by measuring small changes in body temperature) and then avoid sex around the time of ovulation. This Church-condoned contraceptive technique is the mirror image of the practice of most animals—who garishly advertise ovulation and avoid sex at all other times. It is a reminder of how far from our ancestors our culture has taken us, and what fundamental changes in us are possible.

For many animals the ovulation cycle is a few weeks in length. Not many species have periods almost exactly equal to the lunar cycle (the time from new moon to new moon). Whether this peculiarity of humans is more than a coincidence—and if so, why it should be—is unknown.

Mammals suckle their young, but only the females are appropriately endowed.* It’s one of the few cases where the definition of a major classification category in biology, or taxon, is determined by the characteristics of only one of the sexes. Giving milk is also hormonally mediated. Mother’s milk is essential for the young, who are born helpless, unable to digest the adult diet. This is another reason that females spend more time with, and therefore have a greater investment in, the young. The males are generally more interested in other things—dominance, aggression, territoriality, many sex partners.

The connection between steroids and aggression applies with surprising regularity across the animal kingdom. Remove the principal source of sex hormones and aggression declines, not just among the mammals and birds, but in lizards and even fish. Treat castrated males with testosterone and the aggression returns. Give estrogen to intact animals and aggression diminishes, again across all these species. The repeated use of these same steroids for the same functions, turning aggression on and off, for so many different animals, is a testament both to their effectiveness and to their antiquity.

Aggression is adaptive, but only in controlled amounts. The repertoire of aggressive behavior is on call, awaiting only to be disinhibited. The steroids, their production titrated by the social environment and the biological clocks, do the disinhibiting. This being the case, why is it that males are so often more aggressive than females? If the females can generate a little less estrogen and a little more testosterone, can’t they become as aggressive as males? Something like gender equality in aggression occurs in wolves, tree squirrels, laboratory mice and rats, short-tailed shrews, ring-tailed lemurs, and gibbons. In the southern flying squirrel, males are not territorial but females are, and most quarrels between the sexes are initiated by the females—and won by them.13 The clear fact that males are more aggressive than females among us humans (where blood plasma testosterone is about ten times greater in men than in women) by no means commits the rest of the animal kingdom, or even the rest of the primates, to the same arrangement.

As anyone knows who has seen a pet tomcat drag himself home after an absence of a day or two—with an eye closed, an ear torn, his fur matted and bloody—testosterone exacts a price. What happens if you take a male animal—let’s say, someone less combative than tomcats out for a night on the town—and equip him with an implant that keeps his testosterone blood levels high? When this is done to sparrows, hardy territorialists, there seems to be no significant increase in the sparrow murder rate. But when male cowbirds are implanted, their numbers markedly decrease;14 many birds are now observed with unusually serious injuries, clearly obtained in combat with their fellows. Unlike sparrows, cowbirds establish dominance hierarchies but do not have core territorial refuges into which they can flee. Bluff can escalate into serious fighting if you’re simultaneously charged up with testosterone and have no tradition of sanctuary. Another steroid deficit: Male birds with artificially high testosterone levels are less inclined to feed their hatchlings.15 Macho males tend to neglect their family responsibilities.

Sex hormones are now manufactured by pharmaceutical companies, and widely used—legally and illegally. We can learn something about their role in Nature by asking why people use them. Anabolic steroids are molecules very like, but usually not identical to, testosterone. They’re taken mainly by: (1) bodybuilders and athletes (who widely believe that certain feats of strength can be accomplished only by young men on steroids); (2) young men who wish to macho up, usually to attract women or other men; and (3) those who wish to disinhibit their meanness (nightclub bouncers, hit men in organized crime, prison guards, and so on).16 The enhanced musculature does not come about through steroids alone; it also requires vigorous and systematic exercise. One of the side effects is facial and back acne. Anabolic steroids don’t seem to grow hair. Large doses lead to dysfunction and atrophy of the testicles—perhaps the body’s response to excessive testosterone titers; too much testosterone is socially sufficiently dangerous that a mechanism may have evolved so that tendencies toward excessive production aren’t passed on to future generations.

Estrogen is taken by women, usually post-menopause or post-hysterectomy, to preserve sexual interest and lubrication, to slow loss of bone calcium, and to achieve a more youthful complexion. Bodybuilding and transsexual women may take anabolic steroids because they strikingly redistribute weight—from thighs to chest and biceps, for example. Transsexual men taking estrogen redistribute weight the other way, grow breasts, and feminize the nipples and areolae; there’s also a general mellowing of temperament. Bearing in mind these consequences of taking sex hormones as an adult, and the much more profound influence they have on the embryo—actually determining which sexual organs will be present—it seems likely that far subtler changes in hormone levels might influence not just dominance, territoriality, aggression, care for the young, gentleness, anxiety level, and talent for conflict resolution, but also sexual appetite and preference.

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Bulls, stallions, and roosters are made into steers, geldings, and capons because humans find their machismo inconvenient—the very same male spirit that the castrators likely admire in themselves. One or two skilled motions of the blade—or a deft bite by a reindeer-herding Lapp woman—and the testosterone levels are down to manageable proportions for the rest of the animal’s life. Humans want their domestic animals to be submissive, easily controlled. Intact males are an awkward necessity; we want just enough of them to father a new generation of captives.

Something similar although less direct happens within the dominance hierarchy. From pit vipers to primates, the loser in ritual combat often experiences a steep decline in testosterone and related sex hormones, making him less likely to challenge the leadership at a later time, and therefore less likely to be injured. On a molecular level, he’s learned his lesson. With fewer circulating steroids, he’s now less ardent in his pursuit of females—at least when high-ranking males are around. This also is to the liking of the alphas. Again, decreases in testosterone levels following defeat are usually much more marked than any increases following victory.

Back to the testicles of sparrows: In a breeding area each little piece of territory has a male sparrow who will defend it against all comers.* Suppose a meddling ornithologist captures one of these territorial males and removes him from the territory. What happens? Other males from adjacent areas—many of them not previously able to defend a territory—move in. Of course they have to threaten and intimidate before they’ll be taken seriously. So the general level of sparrow anxiety rises, both among the newcomers and among unreplaced sparrows in adjacent territories. Political tensions become high. If now we monitor the bloodstreams of the sparrows in the course of their disputes (which from our point of view, of course, seem petty, but to them it’s Quemoy and Matsu), we find that everyone’s testosterone level has risen—the newly introduced males who are trying to establish their territories, and the males of neighboring territories who are now required to do more in the way of defending than has been their recent practice. Something similar is true for many animals.

Those who have more testosterone, by and large, become more aggressive. Those who need more testosterone, by and large, generate it. Testosterone seems to play a vital role as both the cause and the effect of aggression, territoriality, dominance, and the rest of the “boys-will-be-boys” constellation of male behavioral traits. This seems to be true for widely differing species, including monkeys, apes, and humans.

In springtime, stimulated by the increasing day length, the testosterone level in male perching birds and songbirds (such as jays, warblers, and sparrows) goes up; they develop plumage, unveil a scrappy temperament, and begin singing. Males with larger repertoires breed earlier and produce more chicks. The repertoires of the most attractive males range up to dozens of distinguishable songs. Musical variety is the means by which more testosterone is converted into more birds.

When eggs are being laid, the male testosterone level remains high; they’re protecting their mates. Once the females begin incubating the eggs and are uninterested in sexual advances, male testosterone levels fall. Suppose that the females are now given estrogen implants so they remain sexually alluring and receptive, despite their new maternal duties. Then the testosterone levels in the males remain high. As long as the female is sexually available, the male is inclined to be nearby and protective.17

These experiments suggest that an important selective advantage may accrue if a species breaks out of the estrus constraint. Continuous female sexual receptivity keeps the male around for all sorts of useful services. This is just what seems to have happened—maybe through a small adjustment in the DNA code for the internal estrogen clock—in our species.

Testosterone-induced behavior must be subject to limits and constraints. If it were carried to counterproductive lengths, natural selection would quickly readjust the concentration of steroids in the blood. Testosterone poisoning to the point of maladaptation must be very rare. In nectar-eating birds, bats, and insects it’s possible to compare the energy expended in male steroid-driven defense against poachers with the energy that could be extracted from the flowers being guarded.* In fact, territoriality typically turns on only when the energy benefit exceeds the energy cost, only when there are so few delectable flowers to suck that it pays for you to expend the effort to chase away the competition. Nectar-eaters are not rigid territorialists. They won’t fight all comers to protect a wasteland of stones. They make a cost-benefit analysis. Even in a rich garden of nectar-bearing flowers, often no territorial behavior is seen in the morning—because plentiful nectar has been accumulating at night when the birds were asleep. In the morning, there’s enough to go around. Toward noon, when birds from far and wide have been feeding and the resource begins to get scarce, territoriality turns on.18 Wings outstretched, beaks lunging, the locals drive away the intruders. Maybe they feel they’ve been nice guys long enough, but now they’ve had it up to here with these foreigners. Fundamentally, though, it’s an economic, not a patriotic decision; practical, not ideological.

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Many animals may do it, but at least among rats and mice it’s well-demonstrated: Fear is accompanied by a characteristic odor, a fear pheromone, easily recognized by others.19 Often, as soon as they sense you’re afraid, your friends and relatives run away—useful for them, but not very helpful for you. It may even encourage the rival or predator who has prompted your fear in the first place.

In the heads of goslings and ducklings and chicks at the moment they peck their way out of the egg is, a classic experiment suggests, a rough knowledge of what a hawk looks like. No one has to teach it to them. Hatchlings know. They also know fear. Scientists make a very simple silhouette—cut out of cardboard, say: There are two projections which could be wings. They flank a body which is longer and rounded at one end and shorter and stumpy at the other. If the silhouette moves with the long projection first, it looks like a flying goose, wings spread, long neck preceding. Move the silhouette overhead, neck first, over the hatchlings and they go about their business. Who’s scared of a goose? Now move the same silhouette stumpy end first—so it looks like a hawk with wings outstretched and long tail trailing—and there’s a flurry of peeps and trepidation. If this experiment has been properly interpreted,20 somehow, inside the sperm and the egg that made that chick, encoded in the ACGT sequence of their nucleic acids, there’s a picture of a hawk.

Perhaps this inborn fear of raptors is akin to the fear of “monsters” that almost all babies manifest around the time they become toddlers. Many predators who are circumspect when a human adult is around would happily attack a toddler. Hyenas, wolves, and large cats are only a few of the predators that stalked early humans and their immediate ancestors. When the child begins to amble off on its own, it helps for it to know—in its marrow—that there are monsters out there. With such knowledge, it’s much more likely to come running home to the grown-ups at the slightest sign of danger. Any mild predisposition in this direction will be resoundingly amplified by selection.*

In grown-up chickens there’s a set of more organized and systematic responses, including specific auditory alarm calls that alert every chicken within hailing distance of the ominous news: A hawk is overhead. The cry announcing an aerial predator is distinctly different from that announcing a ground predator—a fox, say, or a raccoon. Since the bird sounding the alarm is also giving away its presence and location to the hawk, we might be tempted to consider it courageous, its behavior evolved through group selection. An individual selectionist might argue—how convincingly is another matter—that the cry works to stir other chickens into motion, whose scurrying might distract the hawk and save the bird that sounded the alarm.

Experiments by the biologist Peter Marler and his colleagues21 show that, at least among cockerels, a propensity to make alarm calls depends very much on whether there’s a companion nearby. With no other bird present, the cockerel may freeze or gaze up into the sky when seeing something like a hawk, but he doesn’t cry out in alarm. He’s more likely to sound the alarm if there’s another bird within earshot; and, significantly, he’s much more likely to cry out if his companion is another chicken—any chicken—rather than, say, a bobwhite. He’s indifferent to plumage, though; chickens with very different color patterns are worthy of being warned. All that counts is that the companion be another domestic fowl. Maybe this is just sloppy kin selection, but it certainly edges toward species solidarity.

So is this heroism? Does the cockerel understand the danger he subjects himself to, and then, despite his fear, bravely cry out? Or is it more likely that squawking when there’s a companion nearby but not when you’re alone is a program in the DNA, and nothing more? See a hawk, see another chicken, cry out, and no agonizing moral struggle. When one of the combatants in a cockfight continues, although bleeding and blinded, to fight to the death, is he displaying “invincible courage” (as an English admirer of cockfighting has described it), or is this just a combat algorithm gotten out of hand, escaping the inhibition subroutines? Indeed, in humans does the hero have a lucid grasp of the danger, or is he or she merely following one of our preprogrammed subroutines? Most heroes report that they just did what came naturally, without much conscious thought.

The two sexes are not equally likely to produce alarm calls. In another study by Peter Marler and his colleagues,22 cockerels cried out in alarm every time a hawk silhouette was presented; but hens made such calls only 13% of the time.* Castrated cockerels are much less likely to sound the alarm—except when they have testosterone implants, in which case the call rate goes back up. So testosterone plays a role not just in dominance hierarchies, sex, territoriality, and aggression, but also in providing early warning of predators, whether we hold the bearer to be hero or automaton.

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Preadolescent female mice have a molecule in theirurine that induces testosterone production in males who get a whiff. In turn, the males’ urine now contains pheromones which, when sniffed by the immature female, quicken her sexual development. She matures early if there are males around, and late if there aren’t—a positive feedback loop that saves unnecessary effort. (As you might expect, female mice who can’t detect odors never come into heat.) What’s more, normal pregnant females who sniff the urine from males of a different strain of mice spontaneously abort their pregnancies; they resorb the embryos back into their bodies and quickly come into heat.23 This is convenient for the alien males. If the resident males don’t like it, it’s up to them to stop strangers from coming around with their abortion-inducing aromas.

In mice, as for many other animals, testosterone begins to be manufactured in earnest at puberty, and that’s when serious aggression against other mice begins. In adult males, the more testosterone, the quicker will be the attack when a strange male appears at the territorial frontiers. Again, castrate the males and their aggressiveness declines. Again, deliver testosterone to the castrates and their aggressiveness increases. Male mice are given to “marking” their environment with tiny dribbles of urine—a practice they pursue with redoubled effort when other mice are around (or when they come upon some unfamiliar object, maybe a hairbrush). Because of embryo resorption, if the males are to leave progeny at all, they must be the chief urinators in their territory. Maybe marking is like nametags on luggage, “no trespassing” signs on private property, or heroic portraits of the national leader in public places. The doughty little mouse is singing “This land is my land” and “She belongs to me.” Even when he’s not physically present he wants passersby to take careful note of his proprietorship. As you might suspect, castrate the mouse and urinary marking declines strikingly; resupply testosterone and his compulsion to mark is rekindled.

Normal female mice are infrequent urinators. They are not inveterate markers. But what happens if anatomically normal female infants are jolted with testosterone? Then they begin marking often. (If a similar experiment is done in dogs, adult females who were given testosterone before birth adopt the urination posture of the males; they lift one leg and trickle the urine down the other—one more indignity visited at the hands of the scientists.) When female rats with ovaries surgically removed are supplied with testosterone, they become aggressive, alternating a masculine propensity for confrontation with distinctly feminine sexual behavior. But one thing about giving testosterone to normal females early in their lives: When they grow up, the males find them much less attractive.

While testosterone in the blood is intimately connected with the expression of aggression in male animals, it is by no means the whole story. There are, for example, molecules in the brain that repress aggression. Hereditary strains of rats that are unusually violent turn out to have less of these inhibitory brain chemicals than more peace-loving strains. Aggressive rats are calmed when there are more of these chemicals in their brains; peaceful rats are agitated when there is less of these chemicals. If you’re a rat, busy watching violence in other rats—mice-killing, say—your level of inhibiting brain chemicals drops.24 You’re now more likely to be violent yourself, and not just toward mice. Your repressed aggressive tendencies have been disinhibited. And everybody else’s. Hostility can then rapidly spread through your group, expressed differently by different individuals. Perhaps that’s what happened with Calhoun’s rats, so confined that aggression and despair spread in waves, reflected and amplified from multiple foci through the community. Violence is contagious.

In experiments performed by Heidi Swanson and Richard Schuster,25 rats were given a complex cooperative task to learn, having to run together over specific floor panels in a particular sequence. If they succeeded, they were rewarded with sugar water; if they didn’t, they found themselves racing around the experimental chamber for the fun of it. Nobody taught them what to do, or at least not directly. It was trial and error. The experiment was tried on pairs of males, pairs of females, pairs of castrated males, and pairs of castrated males with testosterone implants. Some of the rats had previously lived alone.

Here’s how it turned out: Females, as well as male castrates, learned fairly quickly. Normal males and castrates with administered testosterone learned much more slowly. Males who had previously lived alone did still worse. Some pairs of previously solitary male rats—pairs with intact testicles as well as pairs of testosterone-jolted castrates—never learned at all.

For the solitary males this is just what you might expect: Because you live alone you have little experience in cooperating, so probably you’re not going to do very well on a demanding test of cooperation. But then, why should females who’ve been living alone be able to figure it out? The answer seems to be that if you’re a solitary male, a loner, and you have to perform a complex task in coordination with someone else, testosterone makes you stupid. Every pair of males who ordinarily lived alone and couldn’t figure out how to pass the test was engaged in violent combat. Communal living, by contrast, tended to calm them down.

Swanson and Schuster conclude that the learning deficits were not so much due to aggression per se, as to aggression in the context of the dominance hierarchy. Those who tended to be the winners in ritualized (or real) combat—almost always it was the same individuals—would strut and saunter with hair erect, threatening, feinting, and occasionally attacking. The subordinates would crouch, close their eyes, and either freeze for long periods or hide. But tendencies to strut or crouch or hide are not well suited for the gymnastic cooperation needed to get that sugar water.

Cooperation has strong democratic overtones. Extreme dominance/submission hierarchies do not. The two are strongly incompatible. In these experiments, females intimidated others and fought as did the males, but today’s winner was often yesterday’s loser, and vice versa—unlike the males. Cowering and freezing were less common, and the female style of aggression didn’t impede social performance as much as her male counterpart’s.

The unfolding richness and complexity of testosterone-induced sexual behavior—dominance, territoriality and all the rest—is one means by which males compete to leave more offspring. It’s not the only possibility. We’ve already mentioned selection at the level of competition among sperm cells, as well as those species in which the male leaves a vaginal plug when he’s done to frustrate those who come after him. Male dragonflies attempt to undo the competition retroactively: Projecting from the male’s penis is a whip-like prong that attaches itself to the mass of sperm previously deposited in the female. When he withdraws, he takes his rivals’ semen with him. How much more direct the dragonflies are than the birds and mammals—our males violent, consumed with jealousy, spitting out threats and accusations, longing for exclusive sexual access to at least one female. The dragonfly male is spared much of this; he merely rewrites his mate’s sexual history.

We’ve concentrated on aggression, dominance, and testosterone because they seem to be of central importance in understanding human behavior and social systems. But there are many other behavior-eliciting hormones fundamental for human well-being, including estrogen and progesterone in females. The fact that complex behavioral patterns can be triggered by a tiny concentration of molecules coursing through the bloodstream, and that different animals of the same species generate different amounts of these hormones, is something worth thinking about when it’s time to judge such matters as free will, individual responsibility, and law and order.

Had Poseidon more carefully measured out whatever it was he gave to Caenis, the matter would not have come to Zeus’ attention. Had Poseidon’s own testosterone titer been lower, or had there been enforceable penalties against gods raping humans, Caenis might have lived a happy and blameless life. As it was, Caeneus was afflicted by hubris, surely; but only because of the rape and its aftermath. He was guilty of disrespect for the gods, but the gods had shown disrespect for her. There is not a hint that the piety of Thessaly would have been troubled had Poseidon left Caenis alone. She had been minding her own business, walking along the beach.


* One of the expert reviewers of this book complains, “I would struggle to help noticing. . You don’t need to be right at armpit level to smell Consider any gym” But gyms are permeated with the accrued perspiration of many athletes over many years. Another expert reviewer notes that molecules like 5-alpha-androstenol are now marketed as alleged aphrodisiacs† Thus, Aristotle’s contention9—echoed millennia later by Sigmund Freud—that “the female is, as it were, a mutilated male” is wrong (Neither is a male a testosterone-altered female, although that’s a little closer to the truth) Women’s bodies do synthesize estradiol, the most potent of the estrogens, from testosterone.* In order, it is conventionally thought, to keep their temperature a few degrees lower than if they were situated inside the body. If the testicles were located within the warm abdomen, sperm cells, it is said, would be sparsely produced and men would be largely sterile. The benefits of external testicles outweigh the risks. But sparrows and scrappy songbirds carry their testes within; and yet, even at the elevated temperatures, their sperm cells seem to be spunky enough Our understanding of why males of some species wear their testes outside, and others inside, seems incomplete.* Exceptions are, in a way, common Male pigeons and doves routinely feed the young a regurgitated “crop milk,” low in sugar, high in fat—just the opposite of the milk of mammals The cock emperor penguin, after incubating the egg for forty days, generates a rich milk in his esophagus When the chick hatches, this is its only food It doubles its weight on Father’s milk and is doing very well by the time the emperor penguin hen returns engorged with tiny shrimp Both sexes of greater flamingos generate a kind of milk which is mixed with their blood and fed to the chicks in the first month of life; each parent provides about a tenth of a liter of this formula each day12 Many animals—wolves, for example—feed their young with regurgitated food, but this is very different from milk* Well, against all sparrow comers. The dominance relationships in the same bit of forest within the communities of, say, owls, bears, raccoons, and humans are generally beneath the notice of sparrows* The question is similar to that posed by the artichoke: Are more calories burned in trying to get to its succulent heart than are afforded by eating the thing?* Just as chicks seem to retain and refine this concern when they get to be adults, so do humans. The fear of non-human predators is another one of our readily available “buttons” that are easy to press in order to manipulate passionate behavior Horror films are one, but hardly the most egregious, example* The sexes differ in other kinds of cries as well For example, when a male comes upon some food he knows the female likes, he often generates a food call. But when the hen finds food, she does not call to the cock; indeed, she does not call at all, unless she has chicks. Hens without families prefer to dine alone.




Chapter 13




THE OCEAN OF BECOMING


Every valley shall be exalted, and every


mountain and hill shall be made low.


Isaiah 40:4





They will manage to cross the ocean of


becoming.


The Maitreyavyakarana (India, about 500 B.C.)1


Let’s for a moment imagine your species is wildly successful. Through the slow evolutionary process it’s become adapted with high precision to its environmental niche. You and all your fellows are now, perhaps even literally, fat and sassy. But, again, especially when you’re so well adapted, any significant genetic change tends not to be in your best interest—just as a random change in some of the microscopic magnetic domains on an audio tape is unlikely to improve the music recorded there. You can’t stop deleterious mutations from happening, just as you can’t prevent a slow degradation of the recorded music, but those mutations are restrained from spreading through the species. Natural selection sifts through the population and quickly disposes of whatever doesn’t work, or doesn’t work as well. It is not considered an extenuating or mitigating circumstance that, by some remote accident, the mutation might be useful in the future. Darwinian selection is for the here and now. Summary judgment is rendered. With careful discrimination, the scythe of selection swings.

But now, let’s imagine that something changes. A small world hurtling through space finds a blue planet smack in its path, and the resulting explosion sprays enough fine particles into the upper atmosphere to darken and cool the Earth; your lake then freezes over, or the savanna vegetation that sustains you shrivels and dies. Or the tectonic engine in the Earth’s interior creates a new island arc and a flurry of volcanic explosions changes the composition of the air, so now more greenhouse gases are released into the atmosphere, the climate warms, and the tidepools and shallow lakes in which you have been luxuriously wallowing begin to dry up—or a dam of glacial ice is breached, creating an inland sea where your congenial desert habitat used to be.

Perhaps the change comes from a biological direction: The animals you eat are now better camouflaged, or defend themselves with greater obstinacy; or animals that eat you have become more adept at the hunt; or your resistance to a new strain of microorganism turns out to be poor; or some plant you habitually eat has evolved a toxin that makes you ill. There can be a cascade of changes—a relatively small physical alteration leading to adaptations and extinctions in a few directly affected species, and further biological changes propagating up and down the food chain.

Now that your world has changed, your once wildly successful species may be reduced to much more marginal circumstances. Now some rare mutation or an improbable combination of existing genes might be much more adaptive. The once-spurned hereditary information may now be given a hero’s welcome, and we are reminded once more of the value of mutation and sex. Or, it may be, no new and more useful genetic information is generated fortuitously in the nick of time, and your species continues its downward drift.

Omnicompetent organisms do not exist. Breathing oxygen lets you be far more efficient in extracting energy from food; but oxygen is a poison for organic molecules, so arrangements for routine handling of oxygen by organic molecules are going to be expensive. The ptarmigan’s white feathers provide superb camouflage in the Arctic snows; but in consequence it absorbs less sunlight and greater demands are placed on its thermoregulatory system. The peacock’s gorgeous tail makes him nearly irresistible to the opposite sex, but also provides a conspicuous luncheon advertisement for foxes. The sickle-cell trait confers immunity to malaria, but condemns many to debilitating anemia. Every adaptation is a trade-off.

Imagine designing a vehicle that drives off roads, flies through the air, and swims underwater. Such a machine, if it could be built at all, would perform none of its functions well. When we need to travel on “unimproved” land we build all-terrain vehicles, when beneath the water, submarines, and when through the air, airplanes. It’s for good reason that these three kinds of vehicles, while roughly of similar shape, in fact tend not to look very much alike. Even so-called “flying boats” are not very seaworthy, nor are they very easy to fly.

Birds that are superb underwater swimmers, such as penguins, or highly capable runners, such as ostriches, tend to lose their ability to fly. The engineering specifications for swimming or running conflict with those for flying. Most species, faced with such alternatives, are forced by selection into one adaptation or the other. Beings that hold all their options open tend to be eased off the world stage. Overgeneralization is an evolutionary mistake.

But organisms that are too narrowly specialized, that perform exceedingly well but only in a single, restrictive environmental niche, also tend to become extinct; they are in danger of making a Faustian bargain, trading their long-term survival for the blandishments of a brilliant but brief career. What happens to them when the environment changes? Like barrelmakers in a world of steel containers, blacksmiths and buggy-whip tycoons in the time of the motorcar, or manufacturers of slide rules in the age of pocket calculators, highly specialized professionals can become obsolete virtually overnight.

If you’re receiving a forward pass in American football, you must keep your eye on the ball. At the same time you must keep your eye on the opposition tacklers. Catching the ball is your short-term objective; running with it after you have it is your longer-term objective. If you worry only about how to outrun the defenders, you may neglect to catch the ball. If you concentrate only on the reception, you may be flattened the moment you receive the ball, and risk fumbling it anyway. Some compromise between short-term and longer-term objectives is called for. The optimum mix will depend on the score, the down, the time remaining, and the ability of the opposing tacklers. For any given circumstance there is at least one optimum mix. As a professional player you would never imagine that your job as a receiver is solely catching passes or solely running with the ball. You will have acquired a habit of quickly estimating the risks and the potential benefits, and the balance between short-term and long-term goals.

Every competition requires such judgments; indeed, they constitute a large part of the excitement of sport. Such judgments must also be made daily in everyday life. And they’re a central and somewhat controversial issue in evolution.

The danger of overspecialization is that when the environment changes, you’re stranded. If you’re superbly adapted to your present habitat, you may be no good in the long term. Alternatively, if you spend all your time preparing for future contingencies—many of them remote—you may be no good in the short term. Nature has posed life a dilemma: to strike the optimum balance between the short-term and the long, to find some middle road between overspecialization and overgeneralization. The problem is compounded, of course, by the fact that neither genes nor organisms have a clue about what future adaptations are possible or useful.

Genes mutate from time to time, and because the environment is changing, it once in a great while happens that a new gene equips its bearer with improved means of survival. It is now more “fit” for its environmental niche. Its adaptive value, its potential to help the organism that bears it leave many viable offspring, has increased. If a particular mutation secures for its possessor a mere 1% advantage over those who lack it, the mutation will be incorporated into most members of a large, freely interbreeding population in something like a thousand generations2—which is only a few tens of thousands of years even for large, long-lived animals. But what if mutations conferring even so small an advantage occur too rarely; or what if several genes must all, improbably, mutate together, each in the right direction, in order to adapt to the new conditions? Then all members of the population may die.

Is there an evolutionary strategy by which individuals and the species can escape from this trap, some trick by which the extremes of overspecialization and overgeneralization can both be avoided? For major environmental catastrophes there may be no such strategy. The dinosaurs had proliferated into an impressive range of environmental niches, and yet not one of them survived the mass extinctions of 65 million years ago. For quick, but less apocalyptic environmental change there are several ways. It helps to reproduce sexually, as we’ve described, because recombination of genes greatly increases the overall genetic variety. It helps to occupy a large and heterogenous territory, and not be too specialized. And it helps if the population breaks up into many nearly isolated subgroups—as was first clearly described by the population geneticist Sewall Wright, who died almost a centenarian in 1987. What follows is a simplification of a complex subject, some aspects of which are under renewed debate.3 But even if it were no more than metaphor, its explanatory power—for mammals, and especially for primates—is considerable.

——


The genes—the instruction manuals written down in the ACGT alphabet of DNA—are mutating. Some genes, in charge of important matters such as the business end of an enzyme, change slowly; indeed, they may change hardly at all in tens or even hundreds of millions of years—because such changes almost always make some molecular machine tool work more poorly, or not at all. Organisms with the mutated gene die (or leave fewer offspring) and the mutation tends not to be passed on to future generations. The sieve of selection strains it out. Other changes that do no damage—in an untranscribed nonsense sequence, or in the blueprints for structural elements involved in orienting the machine tool, say, or draping it over a molecular jig—can spread through future generations quickly, because an organism bearing the new mutation will not be eliminated by selection: In the code for structural elements, the particular sequence of As, Cs, Gs, and Ts hardly matters at all; what’s needed are placeholders, any sequence that codes for the shape of a subcellular handle, say, never mind which amino acids the handle is made of. Changes in ACGT sequences that are ignored anyway also won’t do any harm. Occasionally an organism hits the jackpot, and a favorable mutation will, in relatively few generations, sweep through the entire population; but the overall genetic change due to favorable mutations is slow, because they happen so rarely.

Some genes will be carried by almost all of the population; others will be present in only a tiny fraction of the population. But not even very useful genes will be carried by everyone, either because the gene is new and there hasn’t been time enough for it to spread through the whole population, or because there are always mutations transforming or eliminating a given gene, even a beneficial one. If the absence of a useful gene isn’t positively lethal, in a big enough population some organisms will always be without it. In general, any given gene is distributed through the population: Some individuals have it, and some don’t. If you divide your species up into smaller, mutually isolated subpopulations, the percent of individuals that carry a given gene will vary from group to group.

There are around ten thousand active genes in a typical “higher” mammal. Any one of them may vary from individual to individual and group to group. A few are extinguished for a time or for all time. A few are spanking new and are being spread quickly through the population. Most are old-timers. How useful any given gene is (in the population of wolves or humans or whatever mammal we have in mind) depends on the environment, and that’s changing too.

Let’s follow one of those ten thousand genes. Maybe it’s for extra testosterone production. But it could be any gene. The fraction of the population possessing this gene, relative to all possible alternative genes, is called the gene frequency.

Imagine now a set of isolated populations of the same species. Maybe they’re troops of monkeys that live in adjacent, nearly identical mountain valleys, separated by impassable mountains. Whatever differences there are in the chances of survival or of leaving descendants in the two groups, it won’t be because one is living in a more favorable physical environment.

Not all values of the gene frequency are equally adaptive. Instead, there’s an optimum frequency in the population. If the gene frequency is too low, maybe the monkeys are insufficiently vigilant in defending themselves against predators. If it’s too high, maybe they kill themselves off in dominance combat. When two isolated populations, in otherwise identical circumstances, have different constellations of active genes, their members will have different Darwinian fitness.

But the optimum frequency of this gene depends on the optimum frequency of other genes, as well as on the fluid and varying environment in which our monkeys must live. There might be more than one optimum frequency, depending on circumstances. The same is true for all ten thousand genes—their optimum frequencies all mutually dependent, all varying as the environment does. For example, a higher frequency of a gene for extra testosterone might be useful in dealing with predators and other hostile groups, provided genes for peacekeeping within the group were also more abundant. And so on. The optima interlace.

So a set of gene frequencies that once made your group superbly adapted may now constitute a marked disadvantage; and gene frequencies that once conferred only marginal fitness may now be the key to survival. What a disturbing concept of existence: Just when you’re most in harmony with your environment, that’s when the ice you’re skating on begins to thin. What you should have been emphasizing, had you been able, is early escape from optimum adaptation—a deliberate fall from grace contrived by the well-adjusted, the elective self-humbling of the mighty. The meaning of “overspecialized” becomes clear. But this is a strategy, we well know from everyday human experience, that privileged populations are almost never willing to embrace. In the classic confrontation between short-term and long, the short-term tends to win—especially when there’s no way to foretell the future.

Yes, they lack foresight. But how could they know? It’s asking a great deal of monkeys to foresee future geological or ecological change. We humans, who with our intelligence ought to be much more capable prophets than monkeys, have difficulty enough foreseeing the future, and still more difficulty acting on our knowledge.4 In military operations, ward-heeler politics, much of corporate strategy, and national response to the challenge of global environmental change, the short-term tends to predominate. So offhand, you might think that precautionary maintenance of a collection of gene frequencies that will be optimum for some future circumstance when no one is even aware of this fact is simply too difficult to arrange. You might think that there’s a flaw in the evolutionary process, that life, under some circumstances, might get stranded.

What could possibly cause the gene frequency in different populations to drift to suboptimal values? Suppose the mutation rate went up because of some new chemical in the environment (belched up from the Earth’s interior), or an increase in the flux of cosmic rays (perhaps from some exploding star halfway across the Milky Way). Then the gene frequencies in isolated populations diversify. You might even get a population that, by accident, winds up with the optimum frequencies needed to adapt to a future need. But that will be very rare. More likely, big changes will be lethal. So an increase in the mutation rate tends mainly to spread out the variation in gene frequencies, but not too much.

The population will, through mutation and selection together, tend to follow the changing circumstances, always working toward the optimum adaptation. If the external conditions vary slowly enough, the population might always be close to the optimal adaptation. Gene frequencies are always in slow motion. This gradual movement, driven by mutation and natural selection in a changing physical and biological environment, is just the evolutionary process outlined by Darwin; and Wright’s continuously changing gene frequencies are a metaphor of natural selection.

——


Up to now each isolated subpopulation we’ve been considering has been large, comprising maybe thousands of individuals or more. But now, Wright’s critical step: Let’s think about small groups, with no more than a few dozen individuals. They tend to become closely inbred. After a few generations, who’s available to mate with except relatives? So let’s look at inbreeding for a moment before considering the evolutionary prospects of small populations.

Some human cultures have sex in private and eat in public, some do it the other way around; some live with their aged relatives, some abandon them, and some eat them; some institute rigid rules that even toddlers must obey, and some let children do almost anything they want; some bury their dead, some burn their dead, and some set them out for the birds to eat; some use cowrie shells for money, some use metal, some paper, and some do without money altogether; some have no gods, some have one god, some have many gods. But all of them abominate incest.

Incest avoidance is one of the few invariables common to the spectacular diversity of human cultures. Sometimes, though, exceptions were made for (who else?) the ruling class. Since kings were gods, or near enough, only their sisters were considered of sufficiently exalted status to be their mates. Mayan and Egyptian royal families were inbred for generations, brothers marrying sisters—the process mitigated, it is thought, by unsanctioned and unrecorded couplings with nonrelatives. The surviving offspring were not conspicuously more incompetent than the usual, run-of-the-mill kings and queens, and Cleopatra, Queen of Egypt—officially the product of many consecutive generations of incestuous matings—was gifted by many standards. The historian Plutarch described her as not incomparably beautiful; still,the contact of her presence, if you lived with her, was irresistible; the attraction of her person, joining with the charm of her conversation, and the character that attended all she said and did, was something bewitching. It was a pleasure merely to hear the sound of her voice, with which, like an instrument of many strings, she could pass from one language to another; so that there were few of the barbarian nations that she answered by an interpreter.


She was fluent not only in Egyptian, Greek, Latin, and Macedonian, but also in Hebrew, Arabic, and the languages of the Ethiopians, the Syrians, the Medes, the Parthians, “and many others.”5 She’s described as “the only human being except Hannibal who [ever] struck fear into Rome.”6 She also gave birth to several apparently healthy children—although they were not fathered by her brother. One of them was Ptolemy XV Caesar, son of Julius Caesar and titled King of Egypt (until murdered at age seventeen by the future Emperor Augustus). Cleopatra certainly does not seem to have exhibited marked physical or intellectual deficits, despite the alleged close relation of her parents.

Nevertheless, inbreeding produces a statistical genetic deficit that takes its toll chiefly in the deaths of infants and juveniles (and we don’t have a good record of Mayan and Egyptian royal children who died at birth or were put to death in infancy). There is considerable evidence for this in many—but by no means all—groups of animals and plants. Even in sexual microorganisms, incest causes striking increases in the deaths of the young.7 In incestuous unions in zoos, mortality in the offspring increased steeply for forty different species of mammals—although some were much more vulnerable to close inbreeding than others.8 In successive brother-sister matings in fruit flies, only a few percent of the offspring survived by the seventh generation.9 In baboons, matings between first cousins result in infants that die, within the first month of life, about 30% more often than in baboon matings where the parents are not close relatives.10 Most normally outbred plants—corn, for example—deteriorate on consistent inbreeding. They become smaller, scrawnier, more withered. That’s why we have hybrid corn. Many plants with both male and female parts are configured, as Darwin first noted, so they cannot easily have sex with themselves (“self-incompatibility” this ultimate incest taboo is called). Many animals, including the primates, have taboos that inhibit mating with close relatives.11

Purebred dogs are prone to deformities and crippling defects. The biologists John Paul Scott and John L. Fuller performed breeding experiments—that is, artificial selection—on five breeds of dogs:In our experiments we began with what were considered good breeding stocks, with a fair number of champions in their ancestry. When we bred these animals to their close relatives for even one or two generations, we uncovered serious defects in every breed.… [C]ocker spaniels [are] selected for a broad forehead with prominent eyes and a pronounced “stop,” or angle between the nose and forehead. When we examined the brains of some of these animals during autopsy, we found that they showed a mild degree of hydrocephaly; that is, in selecting for skull shape, the breeders had accidentally selected for a brain defect in some individuals. Besides all this, in most of our strains only about 50 per cent of the females were capable of rearing normal, healthy litters, even under nearly ideal conditions of care.Among other dog breeds, such defects are quite common.12


Similar genetic deficits are found in the limited data available on human incest in modern times. The increased infant death rate resulting from first cousin marriages13 is only about 60%. But in a Michigan study14 in the middle 1960s, eighteen children from brother-sister and father-daughter matings were compared with a control group of children from non-incestuous matings. Most of the children of incest (eleven out of eighteen) died within their first six months, or showed serious defects—including severe mental retardation. No history of such defects was found in the parents or their families. The remaining children seemed normal in intelligence and in all other respects, and were recommended for adoption. None of the children in the control group died or was institutionalized. Compared to brother-sister and father-daughter matings in other animals, though, these mortality and morbidity rates seem high; perhaps incestuous unions that produce abnormal children were more likely to come to the attention of the scientists making the study.

The dangers of repeated inbreeding seem so clear that we can safely conclude that unsanctioned sexual unions, impregnations of Queens of Egypt by someone other than the Pharaoh, occurred among Cleopatra’s immediate ancestors. Even a few sibling matings in consecutive generations would probably have led to death, or at least to a Cleopatra very different from the vital individual history reveals to us. But one generation of outcrossing goes far to cancel the previous inbreeding.

Inbreeding is a particular danger in very small groups, because in them it can hardly be avoided. If a new nonlethal mutation occurs in one individual, it either gets lost—because, for example, its bearer has no offspring—or it’s not many generations before it’s in nearly everybody, even if it’s slightly maladaptive. So now most males in the population have, say, a little too much testosterone; the conflicts and the distractions of conflict are taking their toll, and the youngsters are not being cared for as they should. The population has wandered from optimum adaptation; if inbreeding is intense, it may be that eventually none of the members of the group leaves offspring.

If inbreeding weren’t so risky, you might think that small populations are the way to get to gene frequency constellations that are not now especially adaptive, but that will be so at some time in the future. If the population is small, then new mutations or new combinations of letters and sequences in the genetic code can propagate through the entire population in only a few generations. New random experiments in biology are being conducted that could not occur in large populations. As a result, almost always, the group goes hurtling away from optimum adaptation. But comparatively rare genes and gene combinations can be tried out so quickly in a small population that it can swiftly cover a lot of ground in the possible range of gene frequencies.

What’s happening here is described as “accidents of sampling,” which have much more profound consequences in small populations than in large ones: Imagine you’re flipping a coin. Your chance of getting one head in one trial or flip is clearly 50%, one chance in two. The coin has only a head and a tail, and it has to turn up one side or the other. With two flips, the full menu of equally possible outcomes is: two tails, a head and a tail, a tail and a head, or two heads. So your chance of getting two consecutive heads is one in four, or, equivalently, one-quarter, or ½ × ½. With three flips, the chance that they’re all heads is one chance in eight (½ × ½ × ½), or one in 23. You can flip ten heads in a row once in about a thousand trials (210 = 1024). (If we’d witnessed only that trial, we might think you’re phenomenally lucky.) But a hundred heads in a row will take about a billion billion trillion trials (2100 roughly equals 1030)—which is the same as forever.

In small populations major accidents of sampling are inevitable; in large populations they are nonexistent. Were a national opinion poll to query three people only, there would be little reason to believe the results—that is, to think these three opinions adequately sampled the opinions of most citizens. One of the individuals polled might, by accident, be a Libertarian or a Vegetarian, a Trotskyite or a Luddite, a Coptic or a Skeptic—all with interesting perspectives, but none an accurate reflection of the general population. Now imagine that the opinions of these three were somehow proportionately amplified to become the opinions of the population of the United States as a whole; a major transformation in national attitudes and politics would have been worked. The same can be true genetically when a few individuals from a large population establish a new and isolated community.

Accidents of sampling happen when the population sampled is very small. In many elections, when the pollsters sample five hundred or a thousand randomly chosen people, the results repeatedly prove to be representative of the nation as a whole.* With five hundred or a thousand truthful random samplings, the findings are accurate to within a few percent. (The variation expected is the square root of the sample size.) If you ask a large number of randomly selected people, you will reliably sample the average*; if you ask only a few, you may sample atypical or fringe opinions. Pollsters would gladly sample smaller populations; it would save them money. But they dare not—the errors would be too large, the sampled opinions too unrepresentative.

As in opinion polls, so it is in the genetics of populations: With a small enough group, substantial deviations † from the average can be sampled and become established. With mutually isolated small groups, many different sets of gene frequencies get tried out—most maladaptive, but a few, fortuitously, poised for the future. This is called genetic drift.

Or suppose that your name is Theodosius Dobzhansky and that you live in New York City. Even if you have ten sons, your name will continue to be “rare and outlandish” so long as you continue to reside in the big city. But move the family to a small town, have many descendants, and Dobzhansky will eventually become a common and unremarkable name. Similarly, any extraordinary hereditary predisposition in the Dobzhansky genes will affect only a tiny fraction of the population while you’re in New York, but might in a few generations become a major genetic feature of the citizenry of the town.15

Is there any way to preserve the accidents of sampling inherent in small groups, while avoiding the slow deterioration intrinsic to incest? Imagine that each group is significantly inbred, but that outbreeding is sometimes indulged in. Individuals from largely isolated subpopulations occasionally find each other and mate, enough to mitigate the more severe genetic consequences of incest. Different constellations of genes will be established in each subpopulation by genetic drift. Each small group will have a different set of hereditary propensities. They will not all, therefore, be optimally adapted to current circumstances. Now that the environment has changed, none of them may be. Being far from optimally adapted, their lives will be hard. Not one of these groups will be as well off as it was earlier. Many groups will die out. Now, though, when the environmental crisis comes, a few of these smaller populations will find themselves, by accident, advantageously situated, “preadapted.”

The trick is to combine the accidents of sampling of small groups (so at least one group will be by chance fortunately poised for the next environmental crisis) with the stability of large groups (so once the new, desirable adaptation is hit upon, it is spread to a substantial population). Because the lucky group—with newly optimal gene frequencies—is also in genetic contact with other groups, its new constellation of adaptive genes is passed on. Other groups acquire the new capabilities, the new mix of traits, the new adaptations; and simultaneously the most dangerous consequences of inbreeding are avoided.

Here then is a trial-and-error mechanism through which a large population can explore the mix of possible gene frequencies. When the adaptations that formerly led to our success now become only marginally useful, we have a way out. Dividing a species into many quite small, fairly inbred populations, but allowing occasional interbreeding among these populations, is the solution Sewall Wright proposed. It avoids both traps, overspecialization and overgeneralization.16 And to the extent that major evolutionary steps occur relatively quickly in small, semi-isolated populations, the relative paucity of intermediate forms in the fossil record—one of the problems that plagued Darwin—would be explained.17

——


No organisms have ever sat down and decided, as a matter of conscious species-wide evolutionary policy, to divide themselves up into small populations, amplify accidents of genetic sampling, and at the same time avoid the more flagrant forms of incest. But, as always happens in the evolutionary process, any species that, by accident, makes appropriate arrangements preferentially reproduces. If enough evolutionary experiments are tried over the immense vistas of time available in the history of life, then very improbable adaptations—in group size, say, or in the balance between inbreeding and outbreeding—can be institutionalized. Here we are talking about the evolution of a mechanism to guarantee continuing evolution, a second-order or meta-evolutionary development.18

What would it feel like from the inside if you were a member of a species that had, through natural selection, made arrangements for genetic drift? You would enjoy living in small groups. You would hate crowds. For accidents of sampling to work on an appropriate time scale, a group might have to comprise no more than one hundred or two hundred individuals, and—according to Wright—would probably be best with only a few dozen members. Groups of six to eight or fewer tend to be unstable; they’re too vulnerable to being wiped out by predators or flood or disease, a different example of accidents of sampling. You would conceive a passionate loyalty to the group, something like intense family feeling, superpatriotism, chauvinism, ethnocentrism. (Especially because most members of your group are close relatives, you might when necessary be moved to something like altruistic or even heroic actions on their behalf.) You would also need to avoid any merger of your group with another, because much bigger groups would inhibit accidents of sampling. So it would be helpful if you conceived a passionate hostility to other groups, a vivid sense of their deficiencies, something like xenophobia or jingoism.

Those other groups are, of course, composed of individuals of the same species as you. They look almost exactly like you. To fan the flames of xenophobia, you must examine them with minute attention and exaggerate whatever differences can be discerned, always to their disadvantage. They have slightly different heredities and slightly different diets, so they don’t smell quite the same as you and yours. If your olfactory powers are sufficiently finely tuned, maybe their scents will render them grotesque, hateful, odious.

It would be even better if you could establish some distinctions. If differences in dress and language are unavailable—having not yet been invented, for example—differences in behavior, posture, or vocalizations would be helpful. Anything that can distinguish your group from the others could work to keep hatreds high and resist merger. Other groups, conveniently, are similarly disposed. These nonhereditary differences between one group and another—even arbitrary differences, only distantly connected with any adaptive advantage, but serving to preserve group independence and coherence—are called, collectively, culture. At a rudimentary level many animals have it.19 Cultural diversity helps preserve genetic drift.

At the same time, avoiding too much inbreeding and guaranteeing at least occasional outbreeding are essential. So you would feel a revulsion about incest, or at least about the most consanguineous matings. Wherever possible, this revulsion would be reinforced by your copying the attitudes of your fellows, by culture. There would be an incest taboo (relaxed perhaps if the population is reduced to only a few survivors). Outbreeding might be officially proscribed—perhaps, among humans, by young men attacking males from other groups who, even accidentally, wander into the neighborhood, or by fathers mourning, as if dead, daughters who run off with foreigners. But despite the pervasive ethnocentrism and xenophobia, now and then you would find members of other, hostile groups unaccountably attractive. Surreptitious matings would occur. (This is, more or less, the theme of Romeo and Juliet, Rudolph Valentino’s The Sheik, and a vast industry of books on romance, targeted at women.)

A promising survival strategy, in short, is this: Break up into small groups, encourage ethnocentrism and xenophobia, and succumb to the occasional sexual temptations provided by the sons and daughters of enemy clans. Devise your own culture: The more your species is capable of learned behavior, the greater the differences that can be established between one group and another. Behavioral differences eventually lead to genetic differences, and vice versa. Incomplete isolation—just the right mix of aloofness and sexual abandon with other groups—generates diversity. And diversity is the raw material on which selection operates.

There seems to be, then, a reason—at the heart of population genetics and evolution—for small semi-isolated groups as the substructure of larger populations, for xenophobia, ethnocentrism, territoriality, incest avoidance, occasional outbreeding, and migration away from the most successful communities. These mechanisms work especially for those species that find themselves in a swiftly changing environment, biologically or physically. Archaebacteria, ants, and horseshoe crabs have not much been in this category; birds and mammals have. So next time you hear a raving demagogue counseling hatred for other, slightly different groups of humans, for a moment at least see if you can understand his problem: He is heeding an ancient call that—however dangerous, obsolete, and maladaptive it may be today—once benefitted our species.

A solution has been found to the problem of how to arrange for gene frequencies to respond quickly to a volatile, changing environment. And the solution seems eerily familiar. After a journey into an abstract world of population genetics and gene frequencies, we turn a corner and suddenly find ourselves gazing at something that looks very much like … ourselves.


* Except when what is expressed in the privacy of the voting booth is too shameful to be admitted to the pollster.† The pejorative flavor that attaches to the word “deviant”—which only means different from the average—suggests the nearly irresistible social pressures, in almost all human societies, to fit in with the crowd. The word “egregious,” meaning exceptionally bad, is Latin for separated out from the herd. Again, the equation of different with bad—sensible for well-adapted populations in the short-term but dangerous in changing times and in the long-term.




Chapter 14




GANGLAND


Brought face to face with these blurred copies


of himself, the least thoughtful of men is


conscious of a certain shock, due perhaps, not


so much to disgust at the aspect of what looks


like an insulting caricature, as to the awakening


of a sudden and profound mistrust of time-


honoured theories and strongly-rooted


prejudices regarding his own position in nature,


and his relations to the under-world of life;


while that which remains a dim suspicion for


the unthinking, becomes a vast argument,


fraught with the deepest consequences, for all


who are acquainted with the recent progress of


the … sciences.


T. H. HUXLEY


Evidence as to Man’s Place in Nature1


The Big Guy, he gets respect He walks by, folks bow. Stick out their hands. Most times, hell touch you. Hands stretch out, Big Guy touch ’em, one after the other. You feel real good. He looks you in the eye and it’s like, you gotta do what he wants. I can’t stand it when he looks at me like that It makes me feel so good, I gotta look down at my feet

He’s crazy about me. The Big Guy, he’d as soon fuck me as look at me. Truth is, he’ll fuck anything that moves. With him you don’t try “I’m not in the mood” or “I got a headache”—all that gets you is hurt and he still gets what he wants. Forget that. You have to give in anyway. So whatever he’s in the mood for, you’re in the mood for. Lucky I really like it with the Big Guy. But who wouldn’t? Anyway, he don’t care what I do on my own time, long as I don’t get knocked up.

A lot of the guys, they don’t get much respect. They’re not much fun to make it with. You got to do it anyway, though. They give you the look and you don’t come running, they beat the shit out of you. Those guys, all they’re interested in is one thing. One time, when the Big Guy is away, I won’t do it and this guy, he picks up a big rock. Huge. He means business, so I have to let him. They’re all like that You don’t come across, they get real pissed off. Those little guys, they think they’re so big. They think they’re hot stuff. They think they can have anyone they like.

When the Big Guy’s around, sometimes he lets ’em and sometimes he don’t. When he’s away on a trip, or when his back is turned, we give the boys a little if we like ’em. You never know, one of ’em might be high rank some day. One of ’em might be the new Big Guy some day. But when the Big Guy’s watching, if he don’t want us to, we don’t even look at the boys. We know what to do. We know our place.

Guys take a lot of stroking. Sometimes what they need is petting or kissing. Sometimes they need more. After, they’re not so grumpy. You come across right away, the guys are nice to you, know what I mean? Before I had my kid, I make it with ten, fifteen guys, one after the other. They can’t wait to get on me.

The Big Guy, sometimes when he gets outta hand, all I gotta do is stroke him a little, and it’s like he can’t remember what was getting him so hot and bothered. The Big Guy, he’s real nice to me. One time my kid’s watching us in the act and tries to stop us. He climb on, hitting Big Guy with his little fists. Big Guy, he don’t touch him. He think it’s funny. He don’t hurt my kid. He don’t hurt me.

Buddy and Squint, they get lots of respect too. Not as much as Big Guy, but almost. Squint’s the Big Guy’s brother. He’s got a thing for me, too. Squint takes the patrols out at night, far away, near the end of our turf. There’s a gang that hangs out on the other side. They’re the Strangers. Sometimes they raid us. We don’t like Strangers. Our guys see Strangers, they go crazy. Strangers come here, they get what they deserve. We catch ’em, we tear ’em apart. Our patrols, they’re out there protecting us and our kids. From Strangers.

One time everybody was tense. You could smell trouble. Me and the kid, we was scared. We was hugging each other real tight. Some Strangers come tearing through. Looking for sex and trouble. Rampage. Well, the Big Guy, he give ’em trouble. He come down on ’em hard. Before Buddy and Squint could help or anything, Big Guy stomp ’em real good. Those Strangers, they run away fast. They stay a little longer, they’d be dead. Best part was, even before the dust settled, they come ’round—Big Guy and Buddy and Squint—to me and the kid and all the others. They make sure we know everything’s all right. Big Guy put his hand on my shoulder. He touch my cheek. He gimme a kiss. Big Guy, he’s all right.

——


I like a little ass, same as the next guy. But what I really like is combat. You’re out on patrol, you gotta be real quiet. You gotta be ready for action. Strangers could be anywhere. Anything could happen at night. Night’s the most exciting.

We catch some Strangers, they’ve had it. One time Squint come on a Stranger mother holding her kid. He take the little brat by a leg and smash its head on the rocks. That’ll teach Strangers to come around. Days later I seen her again, real sad, carrying that dead baby like it’s still alive. But that’s the way it goes. Strangers mess with our turf, they get what’s coming.

Big Guy, he don’t go out on patrols no more. In the old days, before Big Guy take over, it’d be him and me and Squint on patrol. That was great. Those Strangers, they come over here to steal our turf and fuck our females. Some of ours, the younger ones, they don’t mind so much—they got a thing about quickies with Strangers. But us guys, we mind. Strangers, they ain’t like us. We don’t watch our step, they pick us off one by one.

They’re fast and they’re quiet. When we can’t catch ’em, sometimes we throw rocks. I’m real good with rocks. I get high up somewhere and they don’t see me, I cripple ’em with rocks, I break their ass. I hurt ’em and they can’t hurt back. Them Strangers, they better not mess with me.

You gotta be careful, though. Old Boss, the boss before Big Guy, he was off chasing Strangers once. Soon as he was gone, some of the guys take his girlfriend—you know, the one he went off on a honeymoon with. They take her into the bushes. They try to cop a fuck on the side. She don’t mind. Boss come back, he don’t get so much respect like before. You really like a female, it gets you into trouble. Especially if you want to be a boss. It turn out OK for him, though. After Big Guy take over, Old Boss, he just spend all his days fucking. His hair’s gray now, but he’s happy.

Sometimes one of those Stranger females, she sashays over here, all young and sassy, looking for a little action—a real piece of ass, you know? Myself, I’d rather fuck ’em than kill ’em. But some of the guys, they get carried away. We don’t like Strangers here. Still, sometimes she’ll suck up to one of the guys and before you know it he sorta ease her into the gang.

In our gang everybody knows their place. Females especially. They do what they’re told. Or else. Sometimes they make believe like they don’t want it, but I know what they really want. Sometimes you gotta slap ’em around a little. Mostly you give ’em a look and right away, they’re shaking their ass, they got that smile, their eyes are staring, they’re moaning. Most of the time they beg for it.

Us guys, we don’t want the Big Guy to get nervous. We show respect. So we let him climb all over us. It’s not real; it’s just for show. We suck up to the Big Guy. I’m high up, but on this I’m like the rest. He’s my boss. If some tight-assed young guy don’t wanna show respect, he better change his mind or he don’t last long.

Big Guy, he’s really something. I seen him fight off two, three, lots of Strangers, all at once, all by himself. One time he save a little kid that fall into the water. Would’ve drowned for sure. Big Guy, he’s got balls.

After Big Guy it’s pretty much what I say goes. I’m high up. Besides Big Guy, hardly anybody gets on me. ’Course, I need help now and then from the other guys. I spend a lot of time stroking them. But that’s OK. You should see some of the guys my kid brother has to let get on him. Sometimes if Big Guy’s pissed off, you can calm him down just by touching his cock. Sometimes you gotta do more. It just means you’re cool.

When there’s enough to eat and there’s no Strangers around, everybody chills out. Guys get calm. In the early afternoon they all get sleepy, you know, and take naps. Not much trouble then. Too much calm, though, you get itchy for patrol.

I come up through the ranks. I don’t get to be number two by accident. When I start out, I’m not grown yet, nobody give me respect. I want respect so bad back then. When I get big enough, some of the other kids, then some of their mothers and sisters, they start giving me respect. Then all the females. Then I gotta start working myself up with the guys. It was hard. Sometimes I gotta beg food from them. Meat especially. Sometimes, when they give me a little piece, I’d grab it all and run. They’d get real pissed off. It wasn’t easy then. Now it’s different. Now everybody give me respect. Even Squint, sometimes. Even the Big Guy, sometimes.

We get on good. I help him, he help me. He scratch my back, I scratch his, know what I mean? I’m real close to him, closer than anybody except maybe Squint. But one time he got mad at me for not showing enough respect. He think he’s gonna teach me some manners. We have a big fight. Lots of other guys join in. More fights break out. More guys jump on. Maybe they’re helping their brother, or maybe they’re nervous about Big Guy and me fighting. Guys who’re fighting ask for help from guys who’re just watching. Pretty soon everybody’s fighting.

But Big Guy, he don’t look at nobody else but me. And he whip my ass. Then he start calming everybody down. I had to respect him. That was like a real Boss. Still, he beat me in front of everybody. One of these days I’m gonna make my move. He’s been good for me. But I want him off me. Someday I’m gonna be all over him.

Right now, though, Big Guy and Squint and me, we gotta stick together. Some of the young guys are getting restless. They want to stick it to us. I know what those guys are like. When they see us they suck up to us. They show respect. But inside, they think “Up yours.” They think, “My time’s gonna come.” Well, my time’s gonna come first.

——


One thing I wouldn’t let even the Big Guy mess with. That’s my kid. That’s where I draw the line. No one messes with him. When we’re out together, scrounging for something to eat, and I see my kid looking up at me, I know I’d sooner die than let anybody hurt him. He feels like that about me too. When the guys—even top guys—threaten me, my kid come over and try to protect me. They respect him for it. ’Course, just like every other kid around here, all he’s really got is his mother. If I don’t protect him, who will? When he was little he’d eat stuff that make him sick. I gotta stop him. I gotta show him what’s good to eat. He really need me then. He still does, more than he know. Sometimes the guys babysit and they seem to like him. But you can’t trust guys.

One of the young guys wanna fuck his mother. She don’t want to. One of these days he gonna hurt her bad. He can fuck his sister, but he should leave his mother alone. When the mood comes over the guys, though, they can’t help themselves. They go crazy. They act like animals.

Sometimes guys go so crazy, they beat a kid to death for nothing, just for being there. A guy, he gets to be a pain in the ass, he gets chewed out by some big shot. So he go look for somebody to kick around, some nobody—some female, some kid. When guys get pissed off it’s no good for anybody—least of all females and kids. You work real hard to get them calm.

One time my sister’s kid, he musta got sick or something. All of a sudden he can’t move his legs no more. He can’t walk. He just drag himself along by his hands. He look real weird. First, folks look away. None of the guys come ’round to babysit no more. Later, they hassle him. Then they attack him. Then they kill him off, snap his neck. I was sad for my sister.

My kid, all he lives for is to be in the gang, get respect, go out on patrol. He’s too little now, but his time’ll come. He’d do anything for a pat from the Big Guy. Me, too. I love it when the Big Guy touches my hand.

And he stop the young guys from fighting. He’s got a look that says “Up your ass.” Most of the time he just flash that look and the guys, they calm down. Grown-ups, they know how far they can go. They make lots of threats. Except for Strangers, though, nobody gets hurt much. But real young guys, they don’t know the difference. After they get to a certain age they can hurt each other bad. I don’t want my kid hurt by some asshole who don’t know his own strength. Big Guy puts a stop to that.

And he takes care of me. The Big Guy—or Buddy, but I know the Big Guy put him up to it—sometimes goes ’round handing out food. Meat especially. Meat’s not so easy to come by. They always give me and the kid some. They give it mostly to the good-looking females, like me, to make sure we’ll come across. But I’d do it for free, anytime he wants. A lot of folks beg for more when they hand the food out. Not me. I don’t have to.

When the guys leave me alone, I spend all my time with my sister, my girlfriends, my grown-up daughter. We watch out for each other. We give each other respect. I’d be nowhere without them.

One time when I was young—before anybody fucked me except for play—I got fed up. I wasn’t getting no respect. I was off by myself taking a walk and I see this cute guy. He don’t see me. He’s a Stranger—you can tell right away—but he’s real cute. Then all of a sudden he’s gone. After, I keep thinking about him. Maybe all Strangers are as cute as him. Maybe Strangers gimme respect. So I go to check ’em out.

It’s a long walk and I don’t wanna run into our patrols. But I get there OK. Pretty soon I find a guy. A Stranger guy. I don’t think he’s the same one I seen the first time, but he’s real cute, too. I give him a look, and I can see he’s eager. There’s two females there, though, his kind, and they’re not happy to see me like he is. They come at me, yelling and scratching and biting, and I run back home. It’s a long way. When I get here, it don’t seem anybody notice I’m gone—except for Mom, of course. She gimme a big hug. I miss Mom.




Chapter 15




MORTIFYING REFLECTIONS


When he bethought him of the first beginning


of all things, he was filled with a yet more


overflowing charity, and would call the dumb


animals, howsoever small, by the names of


brother and sister, forasmuch as he recognized


in them the same origin as in himself.


ST. BONAVENTURA


The Life of St. Francis1





We are astonished to see how slight and how


few are the differences, and how manifold and


how marked are the resemblances.


CHARLES BONNET


Contemplation de la Nature


(1781), on comparing apes and humans.2


Early in the fifth century B.C., Hanno of Carthage set sail into the western Mediterranean with a fleet of sixty-seven ships, each with fifty oars, carrying altogether thirty thousand men and women. Or at least this is what he claimed in the Periplus—a chronicle that was posted in one of the many temples consecrated to the god Baal after his return home. Sailing through the Straits of Gibraltar, he turned south, establishing cities along the West African coast as he went, including present-day Agadir, Morocco. Eventually, he came to a land filled with crocodiles and hippopotami and many groups of people, some herders, some “wild men,” some friendly, some not. The interpreters he had brought from Morocco could not understand the languages spoken here. He sailed by what is now Senegal, Gambia, and Sierra Leone. He passed a great mountain from which a fire reached “to heaven,” and from which, night and day, “streams of fire flowed into the sea.” This is, almost certainly, the Mount Cameroon volcano just east of the delta of the River Niger. He may have gone almost as far as the Congo before returning.

In the last of eighteen short paragraphs in his Periplus, Hanno describes finding, just before turning back, an island in an African lake,full of wild men. By far the majority of them were women with hairy bodies. The interpreters called them “gorillas.”


The males escaped by climbing precipices and hurling stones. But the females were not so lucky.We captured three women … who bit and scratched … and did not want to follow. So we killed them and flayed them and took their skins to Carthage.


Modern scholars take these beseiged and mutilated beings to be either what we today call gorillas, or chimpanzees. One of the details, the throwing of stones by the males, suggests to us that they were chimps. The Periplus is the earliest firm historical account we have of a first contact between apes arid humans.3

——


The ancient Mayan authors of the Popol Vuh considered monkeys to be the product of the last botched experiment conducted by the gods before they finally got it right and managed to create us. The gods meant well, but they were fallible, imperfect artisans. Humans are hard to make. Many peoples in Africa, Central and South America, and the Indian subcontinent thought of apes and monkeys as beings with some deep connection to humans—aspirant humans, perhaps, or failed humans, demoted for some grave transgression against divine law, or voluntary exiles from the self-discipline demanded by civilization.

In ancient Greece and Rome the similarity of apes or monkeys with humans was well-known—indeed, it was stressed by Aristotle* and Galen. But this led to no speculations about common ancestry. The gods who had made humans were also in the habit of changing themselves into animals to rape or seduce young women: Like the centaurs and the Minotaur, the offspring of these unions were chimeras, part beast, part human. Still, no ape chimeras are prominent in the myths of Greece and Rome.

In India and ancient Egypt, though, there were monkey-headed gods, and in the latter large numbers of mummified baboons—indicating that they were cherished if not worshipped. A monkey apotheosis would have been unthinkable in the post-classical West—in part because the Judaeo-Christian-Islamic religion came of age where nonhuman primates were rare or absent, but mainly because the worship of animals (for example, the Golden Calf of the Israelites) was singled out as an abomination: They were pedaling away from animism as fast as they could. Apes were not widely available for examination in Europe until about the sixteenth century; the so-called Barbary ape of North Africa and Gibraltar—which is what Aristotle and Galen apparently described—is actually a monkey, a macaque.

Without exposure to the beasts most like men, it was difficult to draw the connection between beasts and men. It was easier by far to imagine a separate creation of each species, with the less vivid similarities between us and other animals (the suckling of the young, say, or five toes on each foot) understood as some trademark idiosyncracy of the Creator. The ape was as far below man, it was asserted, as man was below God. So, when, after the Crusades, and especially beginning in the seventeenth century, the West came to know monkeys and apes better, it was with a sense of embarrassment, shame, a nervous snigger—perhaps to disguise the shock of recognition at the family resemblance.

The Darwinian idea that monkeys and apes are our closest relatives brought the discomfort to the conscious level. You can still see the unease today in the conventional associations with the word “ape”: to copy slavishly, to be outsized and brutal. To “go ape” is to revert, to become wild, untamed. When we handle something idly, in an exploratory way, we’re “monkeying around.” To “make a monkey” out of someone is to humiliate him. A “little monkey” is a mischievous or playful child. A “monkeyshine” is a prank. To “go bananas” is to lose control—reflecting the fact that monkeys and apes, who indeed love bananas, are not subject to the same social restraints that we are. In Christian Europe in the Middle Ages and early Renaissance, monkeys and apes were emblematic of extreme ugliness, of a doomed craving for the status of humans, of ill-gotten wealth, of a vengeful disposition, of lust and foolishness and sloth.5 They were accessories—because of their susceptibility to temptation—in the “Fall of Man.” For their sins, it was widely held, apes and monkeys deserved to be subjugated by humans. We seem to have weighed these beings down with a heavy burden of symbols, metaphors, allegories, and projections of our own fears about ourselves.

——


Before the outside world knew anything of his long effort to understand evolution, Darwin wrote telegraphically in his 1838 “M” notebook: “Origin of man now proved … He who understands baboon would do more towards metaphysics than [the philosopher John] Locke.”6 But what does it mean to understand a baboon?

One of the earliest scientific studies of the chimpanzee in its natural African habitat was made by Thomas N. Savage, a Boston physician. Writing in early Victorian times, he concluded:They exhibit a remarkable degree of intelligence in their habits, and, on the part of the mother, much affection for their young … [But] they are very filthy in their habits … It is a tradition with the natives generally here, that they were once members of their own tribe: that for their depraved habits they were expelled from all human society, and, that through an obstinate indulgence of their vile propensities, they have degenerated into their present state and organisation.7


Something was bothering Thomas N. Savage, M.D. “Filthy,” “depraved,” “vile,” and “degenerate” are terms of abuse, not scientific description. What was Savage’s problem? Sex. Chimpanzees have an obsessive, unself-conscious preoccupation with sex that seems to have been more than Savage could bear. Their zesty promiscuity may include dozens of seemingly indiscriminate heterosexual copulations a day, routine close mutual genital inspections, and what at first looks very much like rampant male homosexuality. This was a time when proper young ladies were abjured not to inquire too closely into the stamens and pistils—“the private parts”—of flowers; the renowned critic John Ruskin would later harumph, “With these obscene processes and prurient apparitions, the gentle and happy scholar of flowers has nothing to do.”8 How was a proper Bostonian physician to describe what he had witnessed among the chimpanzees?

And if he did describe it, even obliquely, did he not run a certain risk—that his readers would conclude he approved what he was chronicling? Or more than “approved.” What had drawn him to chimpanzees in the first place? Why did he insist on writing about them? Were there no worthier matters deserving of his attention? Perhaps, he felt obliged to ensure that even a casual reader would note the great distance separating Thomas Savage from the subjects of his study.*

——


William Congreve was the leading playwright of the English comedy of manners around the turn of the eighteenth century. The monarchy had been restored after a bloody struggle with the Puritan religious schismatics who gave their name to rigidity on sexual morality. Each age is repelled by the excesses of the last, so this was a time of moral permissiveness, at least among the dominant elite. Their sigh of relief was almost audible. But Congreve was not their apologist. His ironical and satirical wit was directed at the pretensions, affectations, hypocrisies, and cynicisms of his age—but especially at the prevailing sexual mores. Here, for example, are three fragments of ruling-class dialogue from his The Way of the World:[O]ne makes lovers as fast as one pleases, and they live as long as one pleases, and they die as soon as one pleases; and then, if one pleases, one makes more.


You should have just so much disgust for your husband as may be sufficient to make you relish your lover.


I say that a man may as soon make a friend by his wit, or a fortune by his honesty, as win a woman with plain dealing and sincerity.9


Bearing in mind Congreve’s role as daring social critic of sexual manners, now consider this excerpt from a 1695 letter he wrote to the critic John Dennis:I can never care for seeing things that force me to entertain low thoughts of my Nature. I don’t know how it is with others, but I confess freely to you, I could never look long upon a monkey without very Mortifying Reflections; tho I never heard any thing to the Contrary, why that Creature is not Originally of a Distinct Species.10


Somehow, the sexual imbroglios of upper-class twits that he chronicled did not generate as many Mortifying Reflections as a visit to the zoo. Plays such as Congreve’s were themselves being criticized as breaking down “the Distinctions between Man and Beast. Goats and Monkeys, if they could speak, would express their Brutality in such Language as This.”11 Monkeys were beginning to bother Europeans. And Congreve put his finger on the problem: What does it say about us if monkeys are our close relatives?

From the earliest encounters that history records between apes and men, to parents hurrying their children past the monkey cages before awkward questions are posed, we’ve felt an unease—and the unease has been greater the more puritanical the observer. “The body of an ape is ridiculous … by reason of an indecent likeness and imitation of man,” wrote the cleric Edward Topsell in his 1607 work Historie of Foure-Footed Beasts. Charles Gore, “a man of rock-like faith” and a successor of Samuel Wilberforce as Anglican Bishop of Oxford, was a conflicted habitué of the London Zoo: “I always return an agnostic. I cannot comprehend how God can fit those curious beasts into his moral order.” He once shook his finger at a chimpanzee and rebuked it aloud, in the presence of an attentive small crowd of which he was wholly unaware: “When I contemplate you, you turn me into a complete atheist, because I cannot possibly believe that there is a Divine Being that could create anything so monstrous.”12 If, say, ducks or rabbits with a penchant for sexual excess were under review, people would not have been nearly so bothered. But it’s impossible to look at a monkey or ape without ruefully recognizing something of ourselves.

Simians have facial expressions, social organization, a system of mutually understood calls, and a style of intelligence that’s familiar. They have opposable thumbs and five fingers on each hand which they use as we do. Some walk upright on two legs, at least occasionally. They are awfully, uncomfortably, like us. Might their mores suggest alternative sexual arrangements that might be erosive of the social fabric?* And other ruminations about human affairs might be roused by close attention to monkeys and apes—on the prevalence of coercion and violence, for example, or about public sanctions on sexual intimidation, rape, and incest. These are weighty and sensitive matters. The behavior of monkeys and apes—particularly the ones that look most like us—is an awkward business. Better to put it aside, better to ignore it, better to study something else. Many people would rather not know.

——


Carl Linnaeus, the eighteenth-century biologist, founded the science of taxonomy—the goal of which is to classify every organism on Earth.14 He set himself the task of recording the similarities and differences of all the plants and animals then known, and arranging them all into a web—or, better, a tree—of relatedness. It was he who introduced many elements of the now-standard classification scheme: species, genus, family, order, class, phylum, and kingdom, moving from less to more inclusive categories. Each of these categories is called a “taxon” (plural, “taxa”). So we humans, for example, are of the animal kingdom, the vertebrate phylum, the class of mammals, the order of primates, the family of Hominidae, the genus Homo, and the species Homo sapiens. In other words, we’re animals, not plants or fungi or bacteria; we have backbones, so we’re not invertebrates such as worms or clams; we have breasts to supply milk to the young, so we’re not reptiles or birds; we’re primates, not rats or gazelles or raccoons; and we’re Hominidae, not orangutans or vervet monkeys or lemurs. We are of the genus Homo, in which taxon there is but one species (although once there were others—maybe many others). This is how we classify ourselves today. And it’s almost the same as what Linnaeus proposed.

After accruing vast experience with his new discipline of taxonomy, classifying thousands of beasts and vegetables, Linnaeus contemplated the status of an animal of special interest—himself. Then he reconsidered. By his standard criteria, Linnaeus would have placed human beings and chimpanzees in the same genus.* His scientific integrity urged him to do so. But he well understood what an abomination, how scandalous such a step would have been judged by the Swedish Lutheran Church—indeed, by every religious establishment of which he knew. So Linnaeus trimmed his sails, made a social compromise, and placed us in a genus by ourselves—although he outraged many by declaring us, with the apes and monkeys, a member of the same order.

It’s hard to fault him. Like Copernicus, Galileo, and Descartes, he was about as brave as his age would allow. Many naturalists placed humans in a separate order; by Darwin’s time this would become the conventional wisdom. Many clerics (and some naturalists) placed us in a separate kingdom. The evidence may not have warranted it, but isolating humans in their own genus, their separate first-class compartment, was a popular step, reassuring to human vanity. In 1788, in a reflective and undefensive mood, Linnaeus wrote:I demand of you, and of the whole world, that you show me a generic character … by which to distinguish between Man and Ape. I myself most assuredly know of none. I wish somebody would indicate one to me. But, if I had called man an ape, or vice versa, I would have fallen under the ban of all the ecclesiastics. It may be that as a naturalist I ought to have done so.16


One of the scientific names for the common chimpanzee then was Pan satyrus. Pan was an ancient Greek deity, part man, part goat, associated with lust and fertility. A satyr was a closely associated chimera—at first represented as a man with a horse’s tail and ears and an erect penis. Clearly the rampant sexuality of chimps was the defining characteristic in this early naming of the species. The modern classification is Pan troglodytes, troglodytes being mythical creatures who live in caves and beneath the Earth—a much less appropriate designation, since chimps reside exclusively on (and slightly above) the Earth. (The Barbary apes of North Africa do sometimes live in caves; the only other primates known routinely to have lived in caves are humans.) Linnaeus had mentioned a Homo troglodytes, but it’s unclear whether he had ape or human in mind. Or something inbetween.

A systematic comparison of the anatomies of apes and humans was performed during the opening salvos of the Darwinian Revolution by T. H. Huxley. He described his research program in these words, notable among other respects for their extraterrestrial perspective:[L]et us endeavour for a moment to disconnect our thinking selves from the mask of humanity; let us imagine ourselves scientific Saturnians, if you will, fairly acquainted with such animals as now inhabit the Earth, and employed in discussing the relations they bear to a new and singular “erect and featherless biped,” which some enterprising traveller, overcoming the difficulties of space and gravitation, has brought from that distant planet for our inspection, well preserved, may be, in a cask of rum. We should all, at once, agree upon placing him among the mammalian vertebrates; and his lower jaw, his molars, and his brain, would leave no room for doubting the systematic position of the new genus among those mammals, whose young are nourished during gestation by means of a placenta, or what are called the “placental mammals” …There would remain then, but one order for comparison, that of the Apes (using that word in its broadest sense), and the question for discussion would narrow itself to this—is Man so different from any of these Apes that he must form an order by himself? Or does he differ less from them than they differ from one another, and hence must take his place in the same order with them?Being happily free from all real, or imaginary, personal interest in the results of the inquiry thus set afoot, we should proceed to weigh the arguments on one side and on the other, with as much judicial calmness as if the question related to a new Opossum. We should endeavour to ascertain, without seeking either to magnify or diminish them, all the characters by which our new Mammal differed from the Apes; and if we found that these were of less structural value, than those which distinguish certain members of the Ape order from others universally admitted to be of the same order, we should undoubtedly place the newly discovered tellurian [terrestrial] genus with them.I now proceed to detail the facts which seem to me to leave us no choice but to adopt the last mentioned course.17


Huxley then compares the skeletal and brain anatomies of apes and humans. The “manlike apes” (chimps, gorillas, orangutans, gibbons, and the gibbon-like siamangs—the first three called “greater” and the last two “lesser” apes) all have the same number of teeth as humans; all have hands with thumbs; none has a tail; all arose in the Old World. The skeletal anatomies of chimps and humans are strikingly similar. And “the difference between the brains of the Chimpanzee and of Man,” he concluded,18 “is almost insignificant.”

From these data, Huxley then drew the straightforward conclusion that contemporary apes and humans are close relatives, sharing a recent ape-like common ancestor. The conclusion scandalized Victorian England. The outraged reaction of the wife of the Anglican Bishop of Worcester was typical: “Descended from apes! My dear, let us hope that it is not true, but if it is, let us pray that it will not become generally known.”19 Here it is again: the fear that knowledge of the true nature of our ancestors might unravel the social fabric.

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In recent years it has been possible to go much further, to the very heart of life, to the Holy of Holies, and compare, nucleotide by nucleotide, the DNA molecules of two animals. We can now quantify the kinship of different species. We are able to establish molecular pedigrees, DNA genealogies, which provide the most powerful and compelling evidence that evolution has occurred, as well as tantalizing clues on its mode and tempo. The new tools of molecular biology have yielded insights wholly unavailable to previous generations.

Every animal with a backbone has a bloodstream in which hemoglobin is the oxygen carrier. Hemoglobin is composed of four different protein chains wrapped about one another. One of them is called beta-globin. A particular region of the ACGT sequence codes for beta-globin in all these animals, but only about 5 percent of the region is occupied by the actual instructions for this protein chain. Much of the remaining 95 percent are nonsense sequences—so here mutations can accumulate without being winnowed out by selection. When the beta-globin regions of the DNA are compared across the primate order,20 humans are found to be more closely related to chimps than to anyone else. (The human-gorilla connection comes in a close second.) A new basis for our chimp connection is uncovered: not just the bones, the organs, and the brains, but also the genes—the very instructions for making chimps and humans—are almost indistinguishable.

The DNA sequence that codes for beta-globin is roughly fifty thousand nucleotides long; that is, along a given strand of the DNA molecule, fifty thousand As, Cs, Gs, and Ts in a particular sequence describe precisely how to manufacture the beta-globin of the species in question. If the sequences of humans and chimpanzees are compared nucleotide by nucleotide, they differ by only 1.7%. Humans and gorillas differ by 1.8%, almost as little; humans and orangutans, 3.3%; humans and gibbons, 4.3%; humans and rhesus monkeys, 7%; humans and lemurs, 22.6%. The more the sequences of two animals differ, the more remote (both in relatedness and, usually, in time) is their last common ancestor.

When ACGT sequences that are mainly active genes are examined, a 99.6% identity is found between human and chimp. At the level of the working genes, only about 0.4% of the DNA of humans is different from the DNA of chimps.21

Another method is first to take the DNA from a human being, unzip the double helix, and separate the two strands. Then do the same for a comparable DNA molecule of some other animal. Put the two strands together and let them link up. You’ve now made a “hybrid” molecule of DNA. Where the complementary sequences are closely the same, the two molecules will tightly bind to each other, forming part of a new double helix. But where the DNA molecules from the two animals differ a great deal, the bonding between the strands will be intermittent and weak, and whole sections of the double helix will be flopping loosely. Now take these hybrid DNA molecules and put them in a centrifuge; spin them up so the centrifugal forces tear the two strands apart. The more similar the ACGT sequences are—that is, the more closely related the two DNA strands are—the more difficult it will be to tear them apart. This method does not rely on selected sequences of DNA information (that coding for beta-globin, for example) but on vast amounts of hereditary material, making up whole chromosomes. The two methods—determining the ACGT sequences of selected portions of DNA, and DNA hybridization studies—give remarkable overall agreement. The evidence that humans are most closely related to the African apes is overwhelming.

On the basis of all the evidence, the closest relative of the human proves to be the chimp. The closest relative of the chimp is the human. Not orangs, but people. Us. Chimps and humans are nearer kin than are chimps and gorillas or any other kinds of ape not of the same species. Gorillas are the next closest relatives, both to chimps and humans. The more remote the kinship—when we go to monkeys or lemurs or, say, tree shrews—the less the similarity in sequence. By these standards, humans and chimps are about as closely related as horses and donkeys, and are closer relatives than mice and rats, or turkeys and chickens, or camels and llamas.22

“All right,” you might say, “maybe chimp anatomy is almost the same as mine. Maybe the chimp’s cytochrome c and hemoglobin are almost the same as mine. But the chimp isn’t nearly as smart as I am, as well-organized, as hardworking, as loving, as moral, as devout. Maybe when the genes for these traits are discovered, bigger differences will be found.” Yes. Maybe you’re right. And even that 99.6% identity can be misleading. A 0.4% difference is substantial, because the DNA in any cell in either species is composed of some 4 billion ACGT nucleotides; of them conservatively 1% are in working, no-nonsense portions of the DNA and constitute the genes as such.

The number of operational ACGT nucleotide pairs that are different between humans and chimpanzees must then be roughly 0.4% times 1% times 4 billion, or 160,000. If these are the working parts of genes each 1,000 nucleotides long, each of which codes for a separate enzyme, then the number of completely different kinds of enzymes that humans have and chimps don’t, or vice versa, would be somewhere around 160,000/1,000 or 160. We recall that enzymes have a powerful leverage; they preside over changes in the chemistry of the cell, which can happen very fast; one enzyme can process a multitude of molecules. A hundred enzymes, if they’re the right enzymes, might make a very big difference. A hundred enzymes seems more than enough to account for Huxley’s metaphorical description of the difference between apes and humans: “a hair in the balance-wheel, a little rust on a pinion, a bend in a tooth of the escapement, a something so slight that only the practised eye of the watchmaker can discover it.” Some enzymes would affect estrus, some stature, some fur, some climbing and leaping abilities, some development of the mouth and larynx, some changes in posture, toes, and gait. Many of them would be for a bigger brain with a bigger cerebral cortex, and new ways of thinking beyond the reach of apes.

What’s more, a hundred enzymes changed is certainly an underestimate. Probably none of the differences between chimps and humans requires entirely new enzymes to be evolved. A small number of changes, maybe only a change in a single nucleotide, is adequate to render an enzyme inoperable or to change its function. And many of the differences may not be in the genes themselves, but in the promoters and enhancers, the regulatory elements of the DNA that control when and for how long certain genes should be operational. So even a 0.4% difference could, for all we know, imply profound differences in certain characteristics.

Still, chimps are nearer relatives to us than any other animal on Earth. A typical difference between your DNA—all of it, including the untranscribed nonsense—and that of any other human being23 is roughly 0.1% or less. By this standard, chimps differ from humans only about 20 times more than we differ from one another. That seems awfully close. We must be very careful that those “mortifying reflections” of which Congreve spoke do not make us exaggerate the differences and blind us to our kinship. If we want to understand ourselves by closely examining other beings, chimps are a good place to start.

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Fledgling students of animal behavior are warned against anthropomorphizing. The word literally means changing into human form—attributing human attitudes and states of mind to other animals whose thoughts are not vouchsafed to us. Fairy tales, Aesop, La Fontaine, Joel Chandler Harris, and Walt Disney are among the foremost exponents of the genre. Darwin was guilty of a kind of anthropomorphizing and, even more flagrantly, so was his student George Romanes. The temptation of sentimental self-deception was considered so insidious, and the sin of anthropomorphizing so grave an error, that an influential school of American psychology arose in the first half of the twentieth century which taught that animals enjoyed no internal mental states, no thoughts and no feelings. Its practitioners talked about “the myth of consciousness.” We must, its founder said, “make a clean break with the whole concept of consciousness.” Real scientists, it was claimed, are concerned with no more than what can be observed of the actual behavior of animals. Sensory inputs go in, behavioral outputs come out, and that’s that. Animals feel no pain. Animals are mechanical black boxes. Behaviorism, as it was called, was an example of the ultrapragmatic streak in American science. It had something in common with Descartes’s automata, although it allowed far less room for free inquiry. It came close to deciding that humans don’t have any thoughts or feelings either.

A concerted but fair-minded attack on at least the more extreme forms of behaviorism has been mounted by the biologist Donald Griffin. In the following passage, Griffin refers to “parsimony”—in seience, the doctrine that in deciding between two adequate explanations, we should choose the simpler. It’s also called “Occam’s Razor.”According to the strict behaviorists, it is more parsimonious to explain animal behavior without postulating that animals have any mental experiences. But mental experiences are also held by behaviorists to be identical with neurophysiological processes. Neurophysiologists have so far discovered no fundamental differences between the structure or function of neurons and synapses in men and animals. Hence, unless one denies the reality of human mental experiences, it is actually parsimonious to assume that mental experiences are as similar from species to species as are the neurophysiological processes with which they are held to be identical. This, in turn, implies qualitative evolutionary continuity (though not identity) of mental experiences among multicellular animals.The possibility that animals have mental experiences is often dismissed as anthropomorphic because it is held to imply that other species have the same mental experiences a man might have under comparable circumstances. But this widespread view itself contains the questionable assumption that human mental experiences are the only kind that can conceivably exist. This belief that mental experiences are a unique attribute of a single species is not only unparsimonious; it is conceited. It seems more likely than not that mental experiences, like many other characters, are widespread, at least among multicellular animals, but differ greatly in nature and complexity. … Extreme forms of behaviorism tend to become little more than irrelevant pleas of willful ignorance …Some behavioral scientists vigorously proclaim that they are not interested in animal awareness even if it does occur. Their antipathy sometimes seems to be so strong as to suggest that they really do not want to know about any thinking in which animals might engage.24

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