Guns, Germs, and Steel
Page 42
Table 18.1 summarizes approximate dates of the appearance of key developments in the main “homelands” of each hemisphere (the Fertile Crescent and China in Eurasia, the Andes and Amazonia and Mesoamerica in the Americas). It also includes the trajectory for the minor New World homeland of the eastern United States, and that for England, which is not a homeland at all but is listed to illustrate how rapidly developments spread from the Fertile Crescent.
This table is sure to horrify any knowledgeable scholar, because it reduces exceedingly complex histories to a few seemingly precise dates. In reality, all of those dates are merely attempts to label arbitrary points along a continuum. For example, more significant than the date of the first metal tool found by some archaeologist is the time when a significant fraction of all tools was made of metal, but how common must metal tools be to rate as “widespread”? Dates for the appearance of the same development may differ among different parts of the same homeland. For instance, within the Andean region pottery appears about 1,300 years earlier in coastal Ecuador (3100 B.C.) than in Peru (1800 B.C.). Some dates, such as those for the rise of chiefdoms, are more difficult to infer from the archaeological record than are dates of artifacts like pottery or metal tools. Some of the dates in Table 18.1 are very uncertain, especially those for the onset of American food production. Nevertheless, as long as one understands that the table is a simplification, it is useful for comparing continental histories.
The table suggests that food production began to provide a large fraction of human diets around 5,000 years earlier in the Eurasian homelands than in those of the Americas. A caveat must be mentioned immediately: while there is no doubt about the antiquity of food production in Eurasia, there is controversy about its onset in the Americas. In particular, archaeologists often cite considerably older claimed dates for domesticated plants at Coxcatlán Cave in Mexico, at Guitarrero Cave in Peru, and at some other American sites than the dates given in the table. Those claims are now being reevaluated for several reasons: recent direct radiocarbon dating of crop remains themselves has in some cases been yielding younger dates; the older dates previously reported were based instead on charcoal thought to be contemporaneous with the plant remains, but possibly not so; and the status of some of the older plant remains as crops or just as collected wild plants is uncertain. Still, even if plant domestication did begin earlier in the Americas than the dates shown in Table 18.1, agriculture surely did not provide the basis for most human calorie intake and sedentary existence in American homelands until much later than in Eurasian homelands.
TABLE 18.1 Historical Trajectories of Eurasia and the Americas
Approximate Date of Adoption
Eurasia
Fertile Crescent
China
England
Plant domestication
8500 B.C.
by 7500 B.C.
3500 B.C.
Animal domestication
8000 B.C.
by 7500 B.C.
3500 B.C.
Pottery
7000 B.C.
by 7500 B.C.
3500 B.C.
Villages
9000 B.C.
by 7500 B.C.
3000 B.C.
Chiefdoms
5500 B.C.
4000 B.C.
2500 B.C.
Widespread metal tools or artifacts (copper and/or bronze)
4000 B.C.
2000 B.C.
2000 B.C.
States
3700 B.C.
2000 B.C.
500 A.D.
Writing
3200 B.C.
by 1300 B.C.
A.D. 43
Widespread iron tools
900 B.C.
500 B.C.
650 B.C.
This table gives approximate dates of widespread adoption of significant developments in three Eurasian and four Native American areas. Dates for animal domestication neglect dogs, which were domesticated earlier than food-producing animals in both Eurasia and the Americas. Chiefdoms are inferred from archaeological evidence, such as ranked burials, architecture, and settlement patterns. The table greatly simplifies a complex mass of historical facts: see the text for some of the many important caveats.
As we saw in Chapters 5 and 10, only a few relatively small areas of each hemisphere acted as a “homeland” where food production first arose and from which it then spread. Those homelands were the Fertile Crescent and China in Eurasia, and the Andes and Amazonia, Mesoamerica, and the eastern United States in the Americas. The rate of spread of key developments is especially well understood for Europe, thanks to the many archaeologists at work there. As Table 18.1 summarizes for England, once food production and village living had arrived from the Fertile Crescent after a long lag (5,000 years), the subsequent lag for England’s adoption of chiefdoms, states, writing, and especially metal tools was much shorter: 2,000 years for the first widespread metal tools of copper and bronze, and only 250 years for widespread iron tools. Evidently, it was much easier for one society of already sedentary farmers to “borrow” metallurgy from another such society than for nomadic hunter-gatherers to “borrow” food production from sedentary farmers (or to be replaced by the farmers).
Native America
Andes
Amazonia
Mesoamerica
Eastern U.S.
by 3000 B.C.
3000 B.C.
by 3000 B.C.
2500 B.C.
3500 B.C.
?
500 B.C.
—
3100–1800 B.C.
6000 B.C.
1500 B.C.
2500 B.C.
3100–1800 B.C.
6000 B.C.
1500 B.C.
500 B.C.
by 1500 B.C.
A.D. 1
1500 B.C.
200 B.C.
A.D. 1000
—
—
—
A.D. 1
—
300 B.C.
—
—
—
600 B.C.
—
—
—
—
—
WHY WERE THE trajectories of all key developments shifted to later dates in the Americas than in Eurasia? Four groups of reasons suggest themselves: the later start, more limited suite of wild animals and plants available for domestication, greater barriers to diffusion, and possibly smaller or more isolated areas of dense human populations in the Americas than in Eurasia.
As for Eurasia’s head start, humans have occupied Eurasia for about a million years, far longer than they have lived in the Americas. According to the archaeological evidence discussed in Chapter 1, humans entered the Americas at Alaska only around 12,000 B.C., spread south of the Canadian ice sheets as Clovis hunters a few centuries before 11,000 B.C., and reached the southern tip of South America by 10,000 B.C., Even if the disputed claims of older human occupation sites in the Americas prove valid, those postulated pre-Clovis inhabitants remained for unknown reasons very sparsely distributed and did not launch a Pleistocene proliferation of hunter-gatherer societies with expanding populations, technology, and art as in the Old World. Food production was already arising in the Fertile Crescent only 1,500 years after the time when Clovis-derived hunter-gatherers were just reaching southern South America.
Several possible consequences of that Eurasian head start deserve consideration. First, could it have taken a long time after 11,000 B.C. for the Americas to fill up with people? When one works out the likely numbers involved, one finds that this effect would make only a trivial contribution to the Americas’ 5,000-year lag in food-producing villages. The calculations given in Chapter 1 tell us that even if a mere 100 pioneering Native Americans had crossed the Canadian border into the lower United States and increased at a rate of only 1 percent per year, they would have saturated the Americas with hunter-gathere
rs within 1,000 years. Spreading south at a mere one mile per month, those pioneers would have reached the southern tip of South America only 700 years after crossing the Canadian border. Those postulated rates of spread and of population increase are very low compared with actual known rates for peoples occupying previously uninhabited or sparsely inhabited lands. Hence the Americas were probably fully occupied by hunter-gatherers within a few centuries of the arrival of the first colonists.
Second, could a large part of the 5,000-year lag have represented the time that the first Americans required to become familiar with the new local plant species, animal species, and rock sources that they encountered? If we can again reason by analogy with New Guinean and Polynesian hunter-gatherers and farmers occupying previously unfamiliar environments—such as Maori colonists of New Zealand or Tudawhe colonists of New Guinea’s Karimui Basin—the colonists probably discovered the best rock sources and learned to distinguish useful from poisonous wild plants and animals in much less than a century.
Third, what about Eurasians’ head start in developing locally appropriate technology? The early farmers of the Fertile Crescent and China were heirs to the technology that behaviorially modern Homo sapiens had been developing to exploit local resources in those areas for tens of thousands of years. For instance, the stone sickles, underground storage pits, and other technology that hunter-gatherers of the Fertile Crescent had been evolving to utilize wild cereals were available to the first cereal farmers of the Fertile Crescent. In contrast, the first settlers of the Americas arrived in Alaska with equipment appropriate to the Siberian Arctic tundra. They had to invent for themselves the equipment suitable to each new habitat they encountered. That technology lag may have contributed significantly to the delay in Native American developments.
An even more obvious factor behind the delay was the wild animals and plants available for domestication. As I discussed in Chapter 6, when hunter-gatherers adopt food production, it is not because they foresee the potential benefits awaiting their remote descendants but because incipient food production begins to offer advantages over the hunter-gatherer lifestyle. Early food production was less competitive with hunting-gathering in the Americas than in the Fertile Crescent or China, partly owing to the Americas’ virtual lack of domesticable wild mammals. Hence early American farmers remained dependent on wild animals for animal protein and necessarily remained part-time hunter-gatherers, whereas in both the Fertile Crescent and China animal domestication followed plant domestication very closely in time to create a food producing package that quickly won out over hunting-gathering. In addition, Eurasian domestic animals made Eurasian agriculture itself more competitive by providing fertilizer, and eventually by drawing plows.
Features of American wild plants also contributed to the lesser competitiveness of Native American food production. That conclusion is clearest for the eastern United States, where less than a dozen crops were domesticated, including small-seeded grains but no large-seeded grains, pulses, fiber crops, or cultivated fruit or nut trees. It is also clear for Mesoamerica’s staple grain of corn, which spread to become a dominant crop elsewhere in the Americas as well. Whereas the Fertile Crescent’s wild wheat and barley evolved into crops with minimal changes and within a few centuries, wild teosinte may have required several thousand years to evolve into corn, having to undergo drastic changes in its reproductive biology and energy allocation to seed production, loss of the seed’s rock-hard casings, and an enormous increase in cob size.
As a result, even if one accepts the recently postulated later dates for the onset of Native American plant domestication, about 1,500 or 2,000 years would have elapsed between that onset (about 3000–2500 B.C.) and widespread year-round villages (1800–500 B.C.) in Mesoamerica, the inland Andes, and the eastern United States. Native American farming served for a long time just as a small supplement to food acquisition by hunting-gathering, and supported only a sparse population. If one accepts the traditional, earlier dates for the onset of American plant domestication, then 5,000 years instead of 1,500 or 2,000 years elapsed before food production supported villages. In contrast, villages were closely associated in time with the rise of food production in much of Eurasia. (The hunter-gatherer lifestyle itself was sufficiently productive to support villages even before the adoption of agriculture in parts of both hemispheres, such as Japan and the Fertile Crescent in the Old World, and coastal Ecuador and Amazonia in the New World.) The limitations imposed by locally available domesticates in the New World are well illustrated by the transformations of Native American societies themselves when other crops or animals arrived, whether from elsewhere in the Americas or from Eurasia. Examples include the effects of corn’s arrival in the eastern United States and Amazonia, the llama’s adoption in the northern Andes after its domestication to the south, and the horse’s appearance in many parts of North and South America.
In addition to Eurasia’s head start and wild animal and plant species, developments in Eurasia were also accelerated by the easier diffusion of animals, plants, ideas, technology, and people in Eurasia than in the Americas, as a result of several sets of geographic and ecological factors. Eurasia’s east-west major axis, unlike the Americas’ north-south major axis, permitted diffusion without change in latitude and associated environmental variables. In contrast to Eurasia’s consistent east-west breadth, the New World was constricted over the whole length of Central America and especially at Panama. Not least, the Americas were more fragmented by areas unsuitable for food production or for dense human populations. These ecological barriers included the rain forests of the Panamanian isthmus separating Mesoamerican societies from Andean and Amazonian societies; the deserts of northern Mexico separating Mesoamerica from U.S. southwestern and southeastern societies; dry areas of Texas separating the U.S. Southwest from the Southeast; and the deserts and high mountains fencing off U.S. Pacific coast areas that would otherwise have been suitable for food production. As a result, there was no diffusion of domestic animals, writing, or political entities, and limited or slow diffusion of crops and technology, between the New World centers of Mesoamerica, the eastern United States, and the Andes and Amazonia.
Some specific consequences of these barriers within the Americas deserve mention. Food production never diffused from the U.S. Southwest and Mississippi Valley to the modern American breadbaskets of California and Oregon, where Native American societies remained hunter-gatherers merely because they lacked appropriate domesticates. The llama, guinea pig, and potato of the Andean highlands never reached the Mexican highlands, so Mesoamerica and North America remained without domestic mammals except for dogs. Conversely, the domestic sunflower of the eastern United States never reached Mesoamerica, and the domestic turkey of Mesoamerica never made it to South America or the eastern United States. Mesoamerican corn and beans took 3,000 and 4,000 years, respectively, to cover the 700 miles from Mexico’s farmlands to the eastern U.S. farmlands. After corn’s arrival in the eastern United States, seven centuries more passed before the development of a corn variety productive in North American climates triggered the Mississippian emergence. Corn, beans, and squash may have taken several thousand years to spread from Mesoamerica to the U.S. Southwest. While Fertile Crescent crops spread west and east sufficiently fast to preempt independent domestication of the same species or else domestication of closely related species elsewhere, the barriers within the Americas gave rise to many such parallel domestications of crops.
As striking as these effects of barriers on crop and livestock diffusion are the effects on other features of human societies. Alphabets of ultimately eastern Mediterranean origin spread throughout all complex societies of Eurasia, from England to Indonesia, except for areas of East Asia where derivatives of the Chinese writing system took hold. In contrast, the New World’s sole writing systems, those of Mesoamerica, never spread to the complex Andean and eastern U.S. societies that might have adopted them. The wheels invented in Mesoamerica as parts of
toys never met the llamas domesticated in the Andes, to generate wheeled transport for the New World. From east to west in the Old World, the Macedonian Empire and the Roman Empire both spanned 3,000 miles, the Mongol Empire 6,000 miles. But the empires and states of Mesoamerica had no political relations with, and apparently never even heard of, the chiefdoms of the eastern United States 700 miles to the north or the empires and states of the Andes 1,200 miles to the south.
The greater geographic fragmentation of the Americas compared with Eurasia is also reflected in distributions of languages. Linguists agree in grouping all but a few Eurasian languages into about a dozen language families, each consisting of up to several hundred related languages. For example, the Indo-European language family, which includes English as well as French, Russian, Greek, and Hindi, comprises about 144 languages. Quite a few of those families occupy large contiguous areas—in the case of Indo-European, the area encompassing most of Europe east through much of western Asia to India. Linguistic, historical, and archaeological evidence combines to make clear that each of these large, contiguous distributions stems from a historical expansion of an ancestral language, followed by subsequent local linguistic differentiation to form a family of related languages (Table 18.2). Most such expansions appear to be attributable to the advantages that speakers of the ancestral language, belonging to food-producing societies, held over hunter-gatherers. We already discussed such historical expansions in Chapters 16 and 17 for the Sino-Tibetan, Austronesian, and other East Asian language families. Among major expansions of the last millennium are those that carried Indo-European languages from Europe to the Americas and Australia, the Russian language from eastern Europe across Siberia, and Turkish (a language of the Altaic family) from Central Asia westward to Turkey.