The Third Chimpanzee: The Evolution and Future of the Human Animal

by Jared Diamond

  Scapegoat killings may also involve the fourth type of genocide: racial or religious persecution. The Nazis’ extermination of Jews and Gypsies was based in part on twisted ideas of “racial purity,” while the list of religious massacres is long. Christian crusaders massacred the Muslims and Jews of Jerusalem in 1099, for example, and French Catholics massacred French Protestants in 1572. Racial and religious motives often contribute to genocides based on land and power struggles as well as those involving scapegoating.

  Murder and War in the Animal World

  Is man the only animal that kills members of his own species? Many writers and some scientists have thought so. The famed twentieth-century biologist Konrad Lorenz argued that animals’ aggressive urges are held in check by instincts, or built-in behaviors, that keep them from murder. This balance became upset in human history when we invented weapons, because our instincts were no longer strong enough to hold back our new powers of killing.

  But studies in recent years have documented murder in many, though certainly not all, animal species. Massacre of a neighboring individual or troop may benefit an animal, if the killer can then take over the neighbor’s territory, food, or females. Attacks, however, also involve risk to the attacker, who might be injured or even killed. Looking at the potential costs and benefits of murder may explain why some species, but not others, kill their own.

  Animals of nonsocial species are solitary. Murders in these species involve just one individual killing another. But in social species—such as lions, wolves, hyenas, and ants—murder may take the form of coordinated group attacks. Members of one troop attack a neighboring troop in a mass killing, or “war.” The form of war varies among species. Attackers may drive off males, or kill them, sparing the females to mate with them. Sometimes, as with wolves, both males and females may be killed.

  In seeking to understand the origins of genocide, we are especially interested in the behavior of our closest relatives, the chimpanzees and gorillas. Until the 1970s any biologist would have thought that humans’ ability to use tools and plan together in groups made us far more murderous than apes—if apes were murderous at all. Discoveries since that time, however, suggest that a gorilla or chimpanzee is as likely as the average human to be murdered.

  Among gorillas, males fight each other over harems of females, and the winner may kill the loser’s infants as well as the loser himself. Such fighting is a major cause of death for infant and adult male gorillas. The typical gorilla mother loses at least one infant to a murderous male in the course of her life, and 38 percent of infant gorilla deaths are due to infanticide, or the murder of infants.

  Chimpanzees are now known to commit murder and wage war. Jane Goodall, a pioneer in studying wild African chimpanzees, documented in detail the extermination of one band of chimps by another between 1974 and 1977. Groups of attackers, including some females, several times traveled into a neighboring troop’s territory and ganged up on individual members of that troop. At least one female in the victim troop was killed along with several males. Other females were forced to join the attackers’ troop. Similar long-term conflicts between groups have been observed for other troops of common chimpanzees, but none for bonobos.

  Genocidal chimps appear to show signs of deliberate intention and basic planning— sneaking quickly, quietly, and nervously into another troop’s territory, waiting in trees, and then swiftly attacking an “enemy” chimp. Chimpanzees also share with us the trait of xenophobia. They recognize members of other bands as different from their own band, and treat them very differently.

  Of all our human hallmarks—art, spoken language, drug use, and more—genocide may be the one that comes to us most directly from our animal ancestors. Common chimps carry out planned killings, exterminations of neighboring bands, wars of territorial conquest, and kidnappings of females. This behavior suggests that one major reason for our human hallmark of group living was defense against other human groups, especially once we had acquired weapons and a large enough brain to plan ambushes. We may have been our own prey, and also the predator that forced us into group living.

  A History of Genocide

  Even if humans are not unique among animals in our murderous ways, could our murderous ways be a sick product of modern civilization? Some modern writers, disgusted by the destruction of “primitive” societies by “advanced” societies, think that hunter-gatherer or premodern societies are the human ideal. They paint a picture of people in such societies as peace-loving “noble savages” who, at worst, commit only isolated murders, not massacres.

  Certainly some premodern societies seem less warlike than others. But when we look at early written history, records show that genocide occurred frequently. The wars of the Greeks and Trojans, the Romans and the people of the African colony of Carthage, and the Assyrians, Babylonians, and Persians ended with the slaughter of the defeated group, or perhaps with the killing of the men and the enslavement of the women. Most people know the biblical story of how the walls of Jericho came tumbling down at the sound of Joshua’s trumpet. Not everyone remembers what happened next. Joshua obeyed the Lord’s command to slaughter the inhabitants of Jericho and a number of other cities as well.

  We find similar episodes in records of the wars of the crusaders, the Pacific islanders, and many other groups. Slaughter has not always followed defeat in war, of course. But it has happened often enough that it must be seen as more than a rare exception in our view of human nature. Between 1950 and the early 1990s alone, the world saw almost twenty episodes of genocide. Two of them claimed more than a million victims (Bangladesh in 1971, Cambodia in the late 1970s). Four others had more than 100,000 victims each. in 1994, for example, more than 800,000 people were killed in genocidal massacres in Rwanda. Genocidal warfare in the neighboring Democratic Republic of Congo has led to the deaths of at least 2.5 million people since 1998.

  Genocide appears to have been part of our prehuman and human heritage for millions of years. in this long history, is there something different about modern genocides? There is no doubt that Joseph Stalin of the Soviet Union and Adolf Hitler of Germany set new records for the number of victims. They had three advantages over killers of earlier centuries: denser population centers, improved communications for rounding up victims, and improved technology for mass killing.

  A child gazes at photographs in Cambodia’s Tuol Sleng Museum of Genocide. Housed in a building that was first a school, then a prison and torture center, the museum commemorates the lives lost in the 1970s during the Cambodian genocide.

  It’s harder to say whether technology makes genocide psychologically easier today. Biologist Konrad Lorenz argued that it does. He reasoned that as we evolved from apes, we depended more and more on cooperation between individuals. Societies could not survive unless humans developed strong inhibitions, or instinctive feelings, against killing other humans. Throughout most of our history, our weapons killed at close range, but modern push-button weapons have bypassed our inhibitions by letting us kill from a distance, without seeing our victims’ faces. This has made it easier for us to stomach mass killings.

  I’m uncertain about whether this psychological argument explains modern genocides. The past seems to have had just as frequent genocides as the present, even if the number of victims was smaller. To understand genocides further, we must consider the ethics—what we consider to be the rules of right and wrong—of killing.

  Ethical Codes—and Why We Break Them

  Our urge to kill is almost always held back by our ethics, our understanding that something (in this case, murder) is wrong, or immoral. The puzzle is: What unleashes the urge to kill?

  One key is that we evolved to think in terms of “us” and “them.” Like chimpanzees, gorillas, and social carnivores such as lions and wolves, early humans lived in bands, each with its own territory. The world was smaller and simpler then. Every “us” knew only a few types of “them,” our immediate neighbors. That remained true for some human gr
oups into modern times.

  In New Guinea, for example, each tribe kept up a shifting network of alliance and war with its closest neighbors. A person might enter the next valley on a friendly visit (never completely without danger) or on a war raid, but there was little chance of being able to travel through a series of several valleys in friendship. The powerful rules about treatment of one’s fellow “us” did not apply to “them,” those dimly understood, neighboring enemies.

  As the world grew larger and more complex for some societies, this tribal territorialism remained. Writings from ancient Greece show that the Greeks saw themselves as “us” and everyone else as “them.” The ideal was not to treat all people equally, but to reward one’s friends and punish one’s enemies. Just like hyena bands or chimpanzee troops, human groups practiced a double standard of behavior. There were strong inhibitions about killing one of “us,” but a green light to kill “them” when it was safe to do so.

  Over time, this ancient double standard has become less acceptable as an ethical code. There has been a tendency toward a more universal code of behavior—one that calls for treating people more equally, toward having similar rules for interacting with different peoples. Genocide conflicts directly with a universal ethical code. So how do people who commit genocide wiggle out of the conflict between their actions and the universal code of ethics that has come to be the modern ideal? Simple. They blame the victim, using one or more of three justifications.

  First, most believers in a universal ethical code still believe it is all right to defend themselves. This is useful because “they” can usually be tricked or driven into some behavior that calls for “our” self-defense. Even Hitler claimed self-defense when he started World War II. He went to the trouble of faking a Polish attack on a German border post.

  Second, having the “right” religion or race or political belief, or claiming to represent progress or a higher level of civilization, is a traditional justification for doing anything, including genocide, to people on the “wrong” side or with the “wrong” belief.

  Finally, our ethical codes regard humans and animals differently. Those who commit genocide in the modern world routinely compare their victims to animals in order to justify the killings. Nazis considered Jews to be subhuman lice. French settlers in Algeria called the local Muslims rats. Boers (white descendants of Dutch settlers in South Africa) referred to black Africans as baboons.

  Americans have used all three of these excuses to justify their treatment of the American Indian. Because we claim to believe in a universal code of ethics, our traditional attitudes and stories about the genocide say that whites killed Indians in selfdefense, that white civilization was superior and destined to keep advancing across the land, and that the victims were savage animals.

  Ishi, who died in 1916, was the sole survivor of an American genocide—the extermination of his people, the Yahi Indians.

  THE LAST OF HIS TRIBE

  ON AUGUST 29, 1911, A STARVING, TERRIFIED Indian named Ishi emerged from a remote canyon in Northern California, where he had been hiding for forty-one years. Ishi was the last survivor of a genocide—the extermination of his people, the Yahi tribe.

  Most of the Yahis were massacred by settlers between 1853 and 1870. Sixteen people survived the final massacre in 1870. They went into hiding in the Mount Lassen wilderness and continued to live as hunter-gatherers. By 1908 their number had dwindled to four. That year, surveyors stumbled on their camp and took all their tools, clothes, and winter food supply. As a result, three ofthe Yahis— Ishi’s mother, his sister, and an old man—died. Ishi remained alone for three more years until he could stand it no longer. He walked out to white civilization, expecting to be killed. Instead, he was employed by the University of California Museum in San Francisco. He died of tuberculosis in 1916.

  Ishi was not just the last member of the Yahi people. He was also known as the last “wild” Indian in the United States. Fifteen years after his death, the white killers of his tribe were still publishing their accounts of the genocide. Today, however, Ishi is remembered as a survivor who, after joining white society, shared his story and his knowledge of Indian language and crafts.

  Looking to the Future

  What genocides can we expect from Homo sapiens in the future? Plenty of trouble spots in the world seem ripe for genocide. Modern weapons permit one person to kill ever larger numbers of victims, far from the battlefield. It is even imaginable that someone could commit universal genocide, killing the entire human race.

  At the same time, I see reasons to hope that the future may not be as murderous as the past. In many countries today, people of different races or religions or ethnic groups live together, with varying degrees of social justice but at least without open mass murder. Some genocides have been interrupted, reduced, or prevented by third parties who intervened to keep the peace.

  Another hopeful sign is that travel, TV, photography, and the Internet let us see people who live ten thousand miles away as human, like us. Technology is blurring the line between “us” and “them” that makes genocide possible. While genocide was considered acceptable or even admirable in the world before first contact, the modern spread of international culture and our knowledge about distant peoples make genocide ever harder to justify.

  But the potential for genocide lies within all of us. As world population grows, conflicts between societies and within them will sharpen. Humans will have more urge to kill one another, and better weapons with which to do it. To listen to stories of genocide is unbearably painful. But if we turn away and do not try to understand this destructive part of human nature, when will it be our turn to become the killers, or the victims?

  PART FIVE

  REVERSING OUR PROGRESS OVERNIGHT

  The ruins of Pueblo Bunito, the largest structure in Chaco Canyon. This onetime Anasazi settlement is now Chaco Culture National Historical Park in New Mexico.

  OUR SPECIES NOW COVERS THE EARTH AND commands a larger share of the planet’s productivity than ever before. That’s the good news. The bad news is that, as the next three chapters will show, we are now reversing our progress much more rapidly than we created it. Our power threatens our own existence. Will we suddenly blow ourselves up, or sink slowly into a stew of global warming, pollution, more mouths to feed with less food, and the loss of species we need to survive? And are these dangers really new ones that arose only after the Industrial Revolution of the late eighteenth and nineteenth centuries?

  Most people believe that Nature exists in a state of balance: predators don’t exterminate their prey; grazing animals don’t overgraze their food sources. In this view, humans are the only misfits. If this were true, Nature would hold no lessons for us, because animals and their environments would never get out of balance.

  It’s true that species don’t naturally become extinct as rapidly as we are now exterminating them, except under rare circumstances—such as the mass die-off sixty-five million years ago, possibly due to an asteroid crashing to earth, that finished the dinosaurs. Still, Nature offers many examples of species exterminating other species. This usually happens when a predator is introduced to a new environment, where it meets prey species that are not used to it. After exterminating some of these species, the predator survives by switching to others.

  Rats, cats, goats, pigs, ants, and even snakes have become killers when they have been carried by humans to new environments. One example is a tree snake native to Australia. During World War II it was accidentally carried on ships or planes to the Pacific island of Guam, which had no snakes. By now the Australian tree snake has wiped out or brought to the brink of extinction most of Guam’s forest bird species, which had no chance to evolve behavior that would defend against snakes.

  We humans are the prime example of a switching predator, one that can switch to new prey when one type of prey becomes scarce or extinct. We eat everything from snails and seaweed to whales, mushrooms, and strawberries. If we overharvest a
species to the point of extinction, we just switch to another food source. For this reason, a wave of extinctions has followed us every time we have moved into an unoccupied part of the globe. Hawaiian bird species died out in great numbers after Polynesians reached Hawaii fifteen hundred years ago, for example.

  What about animals? Do they ever destroy their own resource base? It doesn’t happen often, because animal populations tend to rise and fall along with their food supply. Still, some animal populations have eaten themselves out of food, and perished. In 1944, twenty-nine reindeer were introduced to St. Matthew Island in the Bering Sea. By 1963 they had multiplied to six thousand. But reindeer eat slow-growing lichens, and on the small island these plants had no chance to recover from reindeer grazing, because the animals had nowhere to migrate. When a harsh winter struck, all the reindeer died except forty-one females and one sterile male, leaving a doomed population on an island littered with skeletons.

  Ecological suicide by animals happens when populations suddenly become free of the forces that usually control their numbers. Humans have recently escaped from the former controls on our numbers. We eliminated predation on us long ago. Modern medicine has greatly reduced the number of deaths from infectious disease. Behaviors that used to limit population size, such as killing our offspring and waging near-permanent war, have become socially unacceptable. Our population continues to grow, but the example of the St. Matthew reindeer teaches us that no population can grow indefinitely.

  Our present condition can be compared to events in the animal world. Like many switching predators, we eliminate some prey species when we colonize a new environment or gain new destructive power. Like some animal populations that escape their growth limits, we risk destroying ourselves by destroying our resource base.