What actually happened to all those vanished Khoisan populations? We don’t know. All we can say for sure is that, in places where Khoisan peoples had lived for perhaps tens of thousands of years, there are now Bantu. We can only venture a guess, by analogy with witnessed events in modern times when steel-toting white farmers collided with stone tool-using hunter-gatherers of Aboriginal Australia and Indian California. There, we know that hunter-gatherers were rapidly eliminated in a combination of ways: they were driven out, men were killed or enslaved, women were appropriated as wives, and both sexes became infected with epidemics of the farmers’ diseases. An example of such a disease in Africa is malaria, which is borne by mosquitoes that breed around farmers’ villages, and to which the invading Bantu had already developed genetic resistance but Khoisan hunter-gatherers probably had not.
However, Figure 19.1, of recent African human distributions, reminds us that the Bantu did not overrun all the Khoisan, who did survive in southern African areas unsuitable for Bantu agriculture. The southernmost Bantu people, the Xhosa, stopped at the Fish River on South Africa’s south coast, 500 miles east of Cape Town. It’s not that the Cape of Good Hope itself is too dry for agriculture: it is, after all, the breadbasket of modern South Africa. Instead, the Cape has a Mediterranean climate of winter rains, in which the Bantu summer-rain crops do not grow. By 1652, the year the Dutch arrived at Cape Town with their winter-rain crops of Near Eastern origin, the Xhosa had still not spread beyond the Fish River.
That seeming detail of plant geography had enormous implications for politics today. One consequence was that, once South African whites had quickly killed or infected or driven off the Cape’s Khoisan population, whites could claim correctly that they had occupied the Cape before the Bantu and thus had prior rights to it. That claim needn’t be taken seriously, since the prior rights of the Cape Khoisan didn’t inhibit whites from dispossessing them. The much heavier consequence was that the Dutch settlers in 1652 had to contend only with a sparse population of Khoisan herders, not with a dense population of steel-equipped Bantu farmers. When whites finally spread east to encounter the Xhosa at the Fish River in 1702, a period of desperate fighting began. Even though Europeans by then could supply troops from their secure base at the Cape, it took nine wars and 175 years for their armies, advancing at an average rate of less than one mile per year, to subdue the Xhosa. How could whites have succeeded in establishing themselves at the Cape at all, if those first few arriving Dutch ships had faced such fierce resistance?
Thus, the problems of modern South Africa stem at least in part from a geographic accident. The homeland of the Cape Khoisan happened to contain few wild plants suitable for domestication; the Bantu happened to inherit summer-rain crops from their ancestors of 5,000 years ago; and Europeans happened to inherit winter-rain crops from their ancestors of nearly 10,000 years ago. Just as the sign “Goering Street” in the capital of newly independent Namibia reminded me, Africa’s past has stamped itself deeply on Africa’s present.
THAT’S HOW THE Bantu were able to engulf the Khoisan, instead of vice versa. Now let’s turn to the remaining question in our puzzle of African prehistory: why Europeans were the ones to colonize sub-Saharan Africa. That it was not the other way around is especially surprising, because Africa was the sole cradle of human evolution for millions of years, as well as perhaps the homeland of anatomically modern Homo sapiens. To these advantages of Africa’s enormous head start were added those of highly diverse climates and habitats and of the world’s highest human diversity. An extraterrestrial visiting Earth 10,000 years ago might have been forgiven for predicting that Europe would end up as a set of vassal states of a sub-Saharan African empire.
The proximate reasons behind the outcome of Africa’s collision with Europe are clear. Just as in their encounter with Native Americans, Europeans entering Africa enjoyed the triple advantage of guns and other technology, widespread literacy, and the political organization necessary to sustain expensive programs of exploration and conquest. Those advantages manifested themselves almost as soon as the collisions started: barely four years after Vasco da Gama first reached the East African coast, in 1498, he returned with a fleet bristling with cannons to compel the surrender of East Africa’s most important port, Kilwa, which controlled the Zimbabwe gold trade. But why did Europeans develop those three advantages before sub-Saharan Africans could?
As we have discussed, all three arose historically from the development of food production. But food production was delayed in sub-Saharan Africa (compared with Eurasia) by Africa’s paucity of domesticable native animal and plant species, its much smaller area suitable for indigenous food production, and its north-south axis, which retarded the spread of food production and inventions. Let’s examine how those factors operated.
First, as regards domestic animals, we’ve already seen that those of sub-Saharan Africa came from Eurasia, with the possible exception of a few from North Africa. As a result, domestic animals did not reach sub-Saharan Africa until thousands of years after they began to be utilized by emerging Eurasian civilizations. That’s initially surprising, because we think of Africa as the continent of big wild mammals. But we saw in Chapter 9 that a wild animal, to be domesticated, must be sufficiently docile, submissive to humans, cheap to feed, and immune to diseases and must grow rapidly and breed well in captivity. Eurasia’s native cows, sheep, goats, horses, and pigs were among the world’s few large wild animal species to pass all those tests. Their African equivalents—such as the African buffalo, zebra, bush pig, rhino, and hippopotamus—have never been domesticated, not even in modern times.
It’s true, of course, that some large African animals have occasionally been tamed. Hannibal enlisted tamed African elephants in his unsuccessful war against Rome, and ancient Egyptians may have tamed giraffes and other species. But none of those tamed animals was actually domesticated—that is, selectively bred in captivity and genetically modified so as to become more useful to humans. Had Africa’s rhinos and hippos been domesticated and ridden, they would not only have fed armies but also have provided an unstoppable cavalry to cut through the ranks of European horsemen. Rhino-mounted Bantu shock troops could have overthrown the Roman Empire. It never happened.
A second factor is a corresponding, though less extreme, disparity between sub-Saharan Africa and Eurasia in domesticable plants. The Sahel, Ethiopia, and West Africa did yield indigenous crops, but many fewer varieties than grew in Eurasia. Because of the limited variety of wild starting material suitable for plant domestication, even Africa’s earliest agriculture may have begun several thousand years later than that of the Fertile Crescent.
Thus, as far as plant and animal domestication was concerned, the head start and high diversity lay with Eurasia, not with Africa. A third factor is that Africa’s area is only about half that of Eurasia. Furthermore, only about one-third of its area falls within the sub-Saharan zone north of the equator that was occupied by farmers and herders before 1000 B.C. Today, the total population of Africa is less than 700 million, compared with 4 billion for Eurasia. But, all other things being equal, more land and more people mean more competing societies and inventions, hence a faster pace of development.
The remaining factor behind Africa’s slower rate of post-Pleistocene development compared with Eurasia’s is the different orientation of the main axes of these continents. Like that of the Americas, Africa’s major axis is north-south, whereas Eurasia’s is east-west (Figure 10.1). As one moves along a north-south axis, one traverses zones differing greatly in climate, habitat, rainfall, day length, and diseases of crops and livestock. Hence, crops and animals domesticated or acquired in one part of Africa had great difficulty in moving to other parts. In contrast, crops and animals moved easily between Eurasian societies thousands of miles apart but at the same latitude and sharing similar climates and day lengths.
The slow passage or complete halt of crops and livestock along Africa’s north-south axis had import
ant consequences. For example, the Mediterranean crops that became Egypt’s staples require winter rains and seasonal variation in day length for their germination. Those crops were unable to spread south of the Sudan, beyond which they encountered summer rains and little or no seasonal variation in daylight. Egypt’s wheat and barley never reached the Mediterranean climate at the Cape of Good Hope until European colonists brought them in 1652, and the Khoisan never developed agriculture. Similarly, the Sahel crops adapted to summer rain and to little or no seasonal variation in day length were brought by the Bantu into southern Africa but could not grow at the Cape itself, thereby halting the advance of Bantu agriculture. Bananas and other tropical Asian crops for which Africa’s climate is eminently suitable, and which today are among the most productive staples of tropical African agriculture, were unable to reach Africa by land routes. They apparently did not arrive until the first millennium A.D., long after their domestication in Asia, because they had to wait for large-scale boat traffic across the Indian Ocean.
Africa’s north-south axis also seriously impeded the spread of livestock. Equatorial Africa’s tsetse flies, carrying trypanosomes to which native African wild mammals are resistant, proved devastating to introduced Eurasian and North African species of livestock. The cows that the Bantu acquired from the tsetse-free Sahel zone failed to survive the Bantu expansion through the equatorial forest. Although horses had already reached Egypt around 1800 B.C. and transformed North African warfare soon thereafter, they did not cross the Sahara to drive the rise of cavalry-mounted West African kingdoms until the first millennium A.D., and they never spread south through the tsetse fly zone. While cattle, sheep, and goats had already reached the northern edge of the Serengeti in the third millennium B.C., it took more than 2,000 years beyond that for livestock to cross the Serengeti and reach southern Africa.
Similarly slow in spreading down Africa’s north-south axis was human technology. Pottery, recorded in the Sudan and Sahara around 8000 B.C., did not reach the Cape until around A.D. 1. Although writing developed in Egypt by 3000 B.C. and spread in an alphabetized form to the Nubian kingdom of Meroe, and although alphabetic writing reached Ethiopia (possibly from Arabia), writing did not arise independently in the rest of Africa, where it was instead brought in from the outside by Arabs and Europeans.
In short, Europe’s colonization of Africa had nothing to do with differences between European and African peoples themselves, as white racists assume. Rather, it was due to accidents of geography and biogeography—in particular, to the continents’ different areas, axes, and suites of wild plant and animal species. That is, the different historical trajectories of Africa and Europe stem ultimately from differences in real estate.
EPILOGUE
THE FUTURE OF HUMAN HISTORY AS A SCIENCE
YALI’S QUESTION WENT TO THE HEART OF THE CURRENT human condition, and of post-Pleistocene human history. Now that we have completed this brief tour over the continents, how shall we answer Yali?
I would say to Yali: the striking differences between the long-term histories of peoples of the different continents have been due not to innate differences in the peoples themselves but to differences in their environments. I expect that if the populations of Aboriginal Australia and Eurasia could have been interchanged during the Late Pleistocene, the original Aboriginal Australians would now be the ones occupying most of the Americas and Australia, as well as Eurasia, while the original Aboriginal Eurasians would be the ones now reduced to downtrodden population fragments in Australia. One might at first be inclined to dismiss this assertion as meaningless, because the experiment is imaginary and my claim about its outcome cannot be verified. But historians are nevertheless able to evaluate related hypotheses by retrospective tests. For instance, one can examine what did happen when European farmers were transplanted to Greenland or the U.S. Great Plains, and when farmers stemming ultimately from China emigrated to the Chatham Islands, the rain forests of Borneo, or the volcanic soils of Java or Hawaii. These tests confirm that the same ancestral peoples either ended up extinct, or returned to living as hunter-gatherers, or went on to build complex states, depending on their environments. Similarly, Aboriginal Australian hunter-gatherers, variously transplanted to Flinders Island, Tasmania, or southeastern Australia, ended up extinct, or as hunter-gatherers with the modern world’s simplest technology, or as canal builders intensively managing a productive fishery, depending on their environments.
Of course, the continents differ in innumerable environmental features affecting trajectories of human societies. But a mere laundry list of every possible difference does not constitute an answer to Yali’s question. Just four sets of differences appear to me to be the most important ones.
The first set consists of continental differences in the wild plant and animal species available as starting materials for domestication. That’s because food production was critical for the accumulation of food surpluses that could feed non-food-producing specialists, and for the buildup of large populations enjoying a military advantage through mere numbers even before they had developed any technological or political advantage. For both of those reasons, all developments of economically complex, socially stratified, politically centralized societies beyond the level of small nascent chiefdoms were based on food production.
But most wild animal and plant species have proved unsuitable for domestication: food production has been based on relatively few species of livestock and crops. It turns out that the number of wild candidate species for domestication varied greatly among the continents, because of differences in continental areas and also (in the case of big mammals) in Late Pleistocene extinctions. These extinctions were much more severe in Australia and the Americas than in Eurasia or Africa. As a result, Africa ended up biologically somewhat less well endowed than the much larger Eurasia, the Americas still less so, and Australia even less so, as did Yali’s New Guinea (with one-seventieth of Eurasia’s area and with all of its original big mammals extinct in the Late Pleistocene).
On each continent, animal and plant domestication was concentrated in a few especially favorable homelands accounting for only a small fraction of the continent’s total area. In the case of technological innovations and political institutions as well, most societies acquire much more from other societies than they invent themselves. Thus, diffusion and migration within a continent contribute importantly to the development of its societies, which tend in the long run to share each other’s developments (insofar as environments permit) because of the processes illustrated in such simple form by Maori New Zealand’s Musket Wars. That is, societies initially lacking an advantage either acquire it from societies possessing it or (if they fail to do so) are replaced by those other societies.
Hence a second set of factors consists of those affecting rates of diffusion and migration, which differed greatly among continents. They were most rapid in Eurasia, because of its east-west major axis and its relatively modest ecological and geographical barriers. The reasoning is straightforward for movements of crops and livestock, which depend strongly on climate and hence on latitude. But similar reasoning also applies to the diffusion of technological innovations, insofar as they are best suited without modification to specific environments. Diffusion was slower in Africa and especially in the Americas, because of those continents’ north-south major axes and geographic and ecological barriers. It was also difficult in traditional New Guinea, where rugged terrain and the long backbone of high mountains prevented any significant progress toward political and linguistic unification.
Related to these factors affecting diffusion within continents is a third set of factors influencing diffusion between continents, which may also help build up a local pool of domesticates and technology. Ease of intercontinental diffusion has varied, because some continents are more isolated than others. Within the last 6,000 years it has been easiest from Eurasia to sub-Saharan Africa, supplying most of Africa’s species of livestock. But interhemispheric
diffusion made no contribution to Native America’s complex societies, isolated from Eurasia at low latitudes by broad oceans, and at high latitudes by geography and by a climate suitable just for hunting-gathering. To Aboriginal Australia, isolated from Eurasia by the water barriers of the Indonesian Archipelago, Eurasia’s sole proven contribution was the dingo.
The fourth and last set of factors consists of continental differences in area or total population size. A larger area or population means more potential inventors, more competing societies, more innovations available to adopt—and more pressure to adopt and retain innovations, because societies failing to do so will tend to be eliminated by competing societies. That fate befell African pygmies and many other hunter-gatherer populations displaced by farmers. Conversely, it also befell the stubborn, conservative Greenland Norse farmers, replaced by Eskimo hunter-gatherers whose subsistence methods and technology were far superior to those of the Norse under Greenland conditions. Among the world’s landmasses, area and the number of competing societies were largest for Eurasia, much smaller for Australia and New Guinea and especially for Tasmania. The Americas, despite their large aggregate area, were fragmented by geography and ecology and functioned effectively as several poorly connected smaller continents.
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