Attractive as an egalitarian foraging society may seem, it has certain drawbacks. Both private property and privacy are kept to a minimum. Without authority or a headman, individuals must resolve, by themselves or with the aid of kin, any disputes they cannot walk away from. And without specialized roles and some kind of hierarchy, a human society cannot grow beyond a certain level of size or complexity.
An early study of the !Kung, by Elizabeth Marshall Thomas, was titled The Harmless People.352 The !Kung have many attractive qualities but harmless they are not. Fighting had been suppressed by the time of Lee’s study, but rock art and historical accounts attest to its prevalence in the past.82 The San fought regularly with their pastoralist Bantu neighbors, often raiding their stock and fending off counterattacks with their poisoned arrows. The Cape San in the Sneeuwburg mountains halted the expansion of the better armed and mounted Boers for 30 years until overwhelmed by the Boers’ greater numbers.83 As to internal violence, the !Kung’s homicide rate, Lee found, is 29.3 per 100,000 person years, some three times that of even the United States.
Disagreements in !Kung groups escalate through the three recognized levels of talk, fighting and deadly fighting. The talk stage also has three sub-levels. It starts as argument, moves up to verbal anger, and ends in za, a mode of pungent and personal sexual insult. These fighting words lead quickly to physical aggression. At that point, or shortly after, the poison arrows come out.
When hit with an arrow, the !Kung quickly cut around the wound and suck out the poisoned blood and lymph; chances of survival are 50-50. Puzzled at the high risks of this kind of conflict, Lee asked the naïve question of why men didn’t use ordinary arrows instead. “To this question,” he reports, “one informant offered an instructive response: ‘We shoot poisoned arrows,’ he said, ‘be cause our hearts are hot and we really want to kill somebody with them.’”
The anthropologist gained another insight into !Kung methods of conflict resolution while conducting interviews about hunting success. Having asked four !Kung hunters how many giraffe and deer they had killed, Lee reports, “it suddenly occurred to me to pose the question: ‘And how many men have you killed?’
“Without batting an eye, ≠ Toma, the first man, held up three fingers; ticking off the names on his fingers, he responded, ‘I have killed Debe from N≠amchoha, and N⁄⁄u, and N!eisi from /Gam.’
“I duly recorded the names and turned to Bo, the next man. ‘And how many have you killed?’
“Bo replied, ‘I shot //Kushe in the back, but she lived.’
“Next was Bo’s younger brother, Samk”xau: ‘I shot old Kan//a in the foot, but he lived.’
“I turned to the fourth man, Old Kashe, a kindly grandfather in his late sixties, and asked: ‘And how many men have you killed?’
“‘I have never killed anyone,’ he replied.
“Pressing him, I asked, ‘Well then, how many men have you shot?’
“‘I never shot anyone,’ he wistfully replied. ‘I always missed.’”84
Ancestral Portrait
It is tempting to suppose that our ancestors were just like us except where there is evidence to the contrary. This is a hazardous assumption. The ancestral human population is separated from people today by some 2,000 generations. In evolutionary time, that is not so long, yet is still time enough for very substantial evolutionary change to have taken place.
Consider that the anatomically modern humans of 100,000 years ago showed no signs of modern behavior. They had no apparent capacity for innovation and may have lacked the faculty of speech. Very significant evolutionary change seems to have occurred in the 50,000-year span that separates them from the behaviorally modern humans of the ancestral population. Yet that is the same span of time that separates the ancestral population from people today, allowing for an equally decisive evolutionary change. And the pace of human evolution may well have accelerated in the last 50,000 years, given the unparalleled changes in environment experienced by the ancestral people as they left their homeland, colonized strange lands and cold climates, and converted from foraging to settled life.
Indeed specific evidence has now emerged suggesting that the human brain has continued to evolve over the last 50,000 years. The evidence, as described in the next chapter, rests on the finding that two new versions of genes that determine the size of the human brain emerged only recently, one around 37,000 years ago and a second at 6,000 years ago. Given the brain’s continued development, the people of 50,000 years ago, despite archaeologists’ tag for them as “behaviorally modern,” may have been less cognitively capable than people today.
The ancestral human population would have lived by hunting and gathering, and its way of life was perhaps not so different from that of foragers like the !Kung San. In its homeland in northeast Africa, the ancestral people were doubtless as skilled at exploiting the plants and animals of their local environment as the San are in theirs. They would have possessed a carefully thought-out suite of tools for hunting, food preparation, and carrying things. To judge by the journey of those who were to leave Africa, they probably knew how to build boats and how to fish.
But their technology would have been considerably less sophisticated than that of the !Kung. The !Kung’s lightweight bows and poisoned arrows represent a high degree of mechanical and biological knowledge. There is no clear evidence that the bow was invented until some 20,000 years ago. It never reached Australia, suggesting it was not known to the ancestral human population.
Without projectile technology, male hunting success in early human societies would have been considerably less spectacular. Large animals would have been hard to kill, so hunters perhaps concentrated on small game that they could run down and spear. “Before effective hunting, males could have focused more on honey and plant foods, so their daily hauls of food did not have to be lower but must have been different,” writes the evolutionary anthropologist Frank Marlowe. But women’s foraging, for plant foods and tubers excavated with digging sticks, may have been much the same as in contemporary foraging societies.85
In appearance, the ancestral human population would certainly have had dark skin as protection against the African sun. They had stronger bones and were thicker set than contemporary people. They would have cut and decorated their hair. From the date assigned to the evolution of the human body louse, which lives only in clothing, the ancestral people must have worn clothes that were sewn to fit the contours of the body tightly enough for the lice to feed.
It is tempting to suppose the ancestral people looked like the San, with their lightish skin and slightly Asian cast of features, or perhaps like the aboriginal tribes of Australia, who have dark skin and wavy hair. But these two groups have been evolving independently for 50,000 years and their appearance is unlikely to have remained unchanged. The ancestral people may have been similar to both but would also have possessed their own distinctive appearance, which cannot at present be reconstructed.
The ancestral people spoke a fully articulate language, which may well have included the click sounds still used by their Khoisan-speaking descendants.
As hunters and gatherers, the ancestral people probably lived in small egalitarian societies, without property or leaders or differences of rank. These groups engaged in constant warfare, defending their own territory or raiding that of neighbors. When they grew beyond a certain size, of 150 or so people, disputes became more frequent, and with no chiefs or system of adjudication, a group would break up into smaller ones along lines of kinship.
Yet these quarrelsome little societies would have contained in embryo the principal institutions of the large modern societies of today. They had some form of religion, a practice that seems as old as language and may have coevolved with it. Religion may have served as an extra cohesive force, besides the bonds of kinship, to hold societies together for such purposes as punishing freeloaders and miscreants or uniting in war.
A sense of fairness and reciprocity governed exchange and
social relationships. Much later, the idea of reciprocity would be extended to non-kin, allowing strangers to be treated as honorary relatives and creating the framework for societies that transcended the kin-bonded tribe.
Warfare may have been a dominant factor in the ancestral population’s existence. A group could attain respite from conflict by finding new territory. Yet it could not have been easy to travel far from the ancestral homeland. Foragers are adapted to surviving in their local environment by their intimate knowledge of its plants and animals. Only one group of people, a little band maybe only a few hundred strong, succeeded in overcoming the daunting odds and leaving the homeland altogether. But by daring so much, they gained the whole world.
5
EXODUS
Let us suppose the members of a tribe, practising some form of marriage, to spread over an unoccupied continent, they would soon split up into distinct hordes, separated from each other by various barriers, and still more effectually by the incessant wars between all barbarous nations. The hordes would thus be exposed to slightly different conditions and habits of life, and would sooner or later come to differ in some small degree. As soon as this occurred, each isolated tribe would form for itself a slightly different standard of beauty; and then unconscious selection would come into action through the more powerful and leading men preferring certain women to others. Thus the differences between the tribes, at first very slight, would gradually and inevitably be more or less increased.
CHARLES DARWIN, THE DESCENT OF MAN
OUT OF AFRICA there are two routes. One is to travel above the northern tip of the Red Sea and through the Sinai desert into the Levant, the lands of the eastern Mediterranean. The other is to cross the Red Sea at its southernmost point, the Bab al-Mandab or Gate of Grief.
For the ancestral people in their East African homeland, the vast desert to their north may have been a serious barrier. But the Gate of Grief was almost on their doorstep.
Today these straits are some 12 miles wide. But 50,000 years ago much of the world’s ocean water was locked up in the glaciers of the Pleistocene ice age, and the straits would have been much narrower. At that date the water level of the Red Sea was some 230 feet lower than at present.86 The straits were never completely closed but at low sea-stands they would have been dotted with islands, an inviting chain of stepping-stones to the southern Arabian peninsula.
“With the blast of thy nostrils the waters were gathered together, the floods stood upright as an heap, and the depths were congealed in the heart of the sea.” Those were Moses’ words of appreciation for the divine wind that parted the waters of the Red Sea, just in time for the Israelites to escape from Egypt and the pharaoh’s pursuing chariot forces.87 Too bad that the epic, if less miraculous, crossing of the first modern humans into the world beyond Africa cannot be reconstructed in equal detail. Still, some essential features of this ancient exodus are clear enough.
FIGURE 5.1. THE ROUTE FROM AFRICA TO THE FORMER CONTINENT OF SAHUL.
Humans left Africa at a time when ice sheets covered northern latitudes of Europe and Asia, and sea levels were some 200 feet lower than now. They probably crossed the Red Sea at its southern entrance and reached India. Generation by generation, people expanded along the coastlines of southern Asia until by 40,000 years ago they had reached the foundered continent of Sahul (now Australia, New Guinea and Tasmania).
This eastward route taken by the first modern humans to leave Africa may reflect a preference for staying within the tropical climates to which they were adapted, or the occupation of the mainland by Homo erectus, or both.
The first, based on genetic analysis, is that there seems to have been just a single emigration of modern humans from Africa. A second genetic inference is that the number of those who left was probably quite small. Indeed it could have been as few as some 150 people, raising the puzzle of why, if one group of people managed to escape from Africa, many more did not do so.
After some differences of opinion, geneticists now seem to agree that the trees drawn on the basis of the Y chromosome and of mitochondrial DNA both point to a single exodus from Africa. “Analysis of mtDNA and Y chromosome diversity support a single East African source of migration out of Africa,” say two geneticists in a recent review.88 If there were many migrations, they add, “they would have had to originate from the same source population in Africa.”
It’s reasonably likely, then, that the first modern humans left Africa in a single group, that they crossed the southern end of the Red Sea and slowly spread, generation by generation, around the coasts of Arabia and Iran until they reached India. Because of the lower sea levels during the Pleistocene ice age, the archaeological evidence of this coastal passage would now lie underwater.
But this version of events is not yet generally accepted. Another possibility, favored by some experts, is that people traveled from Africa to India by a northern route, across the top of the Red Sea and through the Levant and Iran.
A third possibility is that there were at least two migrations, one to the north and the Levant, the other to the south and India. This theory is favored by archaeologists who have reservations about the reliability of genetic inferences. But if the geneticists are right that there was only one migration, a choice must be made between the northern route, across the top of the Red Sea, and the southern route, across the sea’s southern end; and the present weight of evidence, at least in the geneticists’ eyes, favors a single exodus via the southern route.
In tracing the movements of the first modern humans across the globe, geneticists’ maps show neat arrows stretching from eastern Africa to India, Australia or Japan, and the arrows unavoidably give the impression that the emigrants were purposefully traveling to these distant endpoints. But of course they were not—they had no maps and no idea of what lay at the end of their journey. In fact, it’s doubtful they they were on a journey at all.
For foraging people, short journeys may be routine but long distance travel, carrying their infants and all necessities, is arduous. Rather than trek determinedly into the unknown, or expose their families to the hazards of exploration for its own sake, it’s more likely that the first modern humans to leave Africa behaved as foragers usually do—they moved a short distance and stayed put. After a number of years, as new births swelled the group’s size, it would have divided so as to prevent the usual discord that wells up in large foraging populations.
Following such splits, one group would stay put while the other moved on into unclaimed territory. Foragers need a lot of space to support themselves, so in a century—five generations—a hunter-gatherer society might spread over a considerable distance, especially if its members had learned the art of coastal fishing and preferred to stay near the water’s edge. Those long distance migrations, in other words, were not made by a single group on a long trek, but were the slow expansion of human populations who took a generation to travel each leg of the journey.
Crossing from Africa to the Arabian peninsula via the Gate of Grief would have required boats. Though archaeologists have found no water craft from this period, people who lived at African sites of the Later Stone Age, which began shortly after 50,000 years ago, could certainly fish, so boat building techniques may well have been familiar to the ancestral human population. If the emigrants left Africa by boat, their descendants may thereafter have moved along coastlines until they reached India.
The coastlines could well have been safer than the interior. Southern Arabia is for the most part an inhospitable desert and would have presented a formidable obstacle to foragers. But from time to time on the geological time scale it enjoys rainy periods. Even within the Pleistocene ice age that gripped the world until 10,000 years ago, there were periods of relative warmth. One, known as oxygen isotope stage 3, peaked around 50,000 years ago. During this warm phase, as well as two earlier ones, southern Arabia was wetter and would have been habitable by hunter-gatherer populations.89
But these spells of favorab
le climate may also have drawn down Neanderthals from the north. The Neanderthals may have thwarted previous attempts by humans in Africa to cross into Arabia, just as they crushed the attempt by anatomically modern humans to penetrate the Levant. By 50,000 years ago, however, the Neanderthals would have faced a different adversary. The ancestral people, with their new gift of language, would have enjoyed better organization and superior weaponry. Though physically weaker than the Neanderthals, the new model of humans may at last have gained an edge over their fierce archaic relatives.
Still, having their families with them, they may well have preferred to keep out of the archaics’ way. So instead of striking out across the interior, they may have expanded along the coastline of southern Arabia, using their boats both as transport and to fish from.
So why was there only one migration of modern humans out of Africa? Could it have been that there was only one way out—the Gate of Grief—and the first people to cross it stayed put on the other side and prevented others from invading their territory? Perhaps more likely is that the odds of survival were small, and only one group of people was fortunate enough to surmount all the daunting obstacles in their path.
Passage to India
How can the long ago journey of those first emigrants be traced? Because of the territorial behavior of the first modern humans, rigorously maintained as they invaded the world outside Africa, everyone essentially stayed in place in their new home, except for those at the head of the wave of advance. The world would thus fill up in a rather orderly way. For thousands of years thereafter, people lived and died in the place where they were born. Populations did not mix, except at a local level under the patrilocal system of hunter-gatherer societies.
Before the Dawn: Recovering the Lost History of Our Ancestors Page 9