Guns, Germs, and Steel: The Fates of Human Societies

by Jared Diamond

  CHAPTER 18

  HEMISPHERES COLLIDING

  THE LARGEST POPULATION REPLACEMENT OF THE LAST 13,000 years has been the one resulting from the recent collision between Old World and New World societies. Its most dramatic and decisive moment, as we saw in Chapter 3, occurred when Pizarro’s tiny army of Spaniards captured the Inca emperor Atahuallpa, absolute ruler of the largest, richest, most populous, and administratively and technologically most advanced Native American state. Atahuallpa’s capture symbolizes the European conquest of the Americas, because the same mix of proximate factors that caused it was also responsible for European conquests of other Native American societies. Let us now return to that collision of hemispheres, applying what we have learned since Chapter 3. The basic question to be answered is: why did Europeans reach and conquer the lands of Native Americans, instead of vice versa? Our starting point will be a comparison of Eurasian and Native American societies as of A.D. 1492, the year of Columbus’s “discovery” of the Americas.

  OUR COMPARISON BEGINS with food production, a major determinant of local population size and societal complexity—hence an ultimate factor behind the conquest. The most glaring difference between American and Eurasian food production involved big domestic mammal species. In Chapter 9 we encountered Eurasia’s 13 species, which became its chief source of animal protein (meat and milk), wool, and hides, its main mode of land transport of people and goods, its indispensable vehicles of warfare, and (by drawing plows and providing manure) a big enhancer of crop production. Until waterwheels and windmills began to replace Eurasia’s mammals in medieval times, they were also the major source of its “industrial” power beyond human muscle power—for example, for turning grindstones and operating water lifts. In contrast, the Americas had only one species of big domestic mammal, the llama / alpaca, confined to a small area of the Andes and the adjacent Peruvian coast. While it was used for meat, wool, hides, and goods transport, it never yielded milk for human consumption, never bore a rider, never pulled a cart or a plow, and never served as a power source or vehicle of warfare.

  That’s an enormous set of differences between Eurasian and Native American societies—due largely to the Late Pleistocene extinction (extermination?) of most of North and South America’s former big wild mammal species. If it had not been for those extinctions, modern history might have taken a different course. When Cortés and his bedraggled adventurers landed on the Mexican coast in 1519, they might have been driven into the sea by thousands of Aztec cavalry mounted on domesticated native American horses. Instead of the Aztecs’ dying of smallpox, the Spaniards might have been wiped out by American germs transmitted by disease-resistant Aztecs. American civilizations resting on animal power might have been sending their own conquistadores to ravage Europe. But those hypothetical outcomes were foreclosed by mammal extinctions thousands of years earlier.

  Those extinctions left Eurasia with many more wild candidates for domestication than the Americas offered. Most candidates disqualify themselves as potential domesticates for any of half a dozen reasons. Hence Eurasia ended up with its 13 species of big domestic mammals and the Americas with just its one very local species. Both hemispheres also had domesticated species of birds and small mammals—the turkey, guinea pig, and Muscovy duck very locally and the dog more widely in the Americas; chickens, geese, ducks, cats, dogs, rabbits, honeybees, silkworms, and some others in Eurasia. But the significance of all those species of small domestic animals was trivial compared with that of the big ones.

  Eurasia and the Americas also differed with respect to plant food production, though the disparity here was less marked than for animal food production. In 1492 agriculture was widespread in Eurasia. Among the few Eurasian hunter-gatherers lacking both crops and domestic animals were the Ainu of northern Japan, Siberian societies without reindeer, and small hunter-gatherer groups scattered through the forests of India and tropical Southeast Asia and trading with neighboring farmers. Some other Eurasian societies, notably the Central Asian pastoralists and the reindeer-herding Lapps and Samoyeds of the Arctic, had domestic animals but little or no agriculture. Virtually all other Eurasian societies engaged in agriculture as well as in herding animals.

  Agriculture was also widespread in the Americas, but hunter-gatherers occupied a larger fraction of the Americas’ area than of Eurasia’s. Those regions of the Americas without food production included all of northern North America and southern South America, the Canadian Great Plains, and all of western North America except for small areas of the U.S. Southwest that supported irrigation agriculture. It is striking that the areas of Native America without food production included what today, after Europeans’ arrival, are some of the most productive farmlands and pastures of both North and South America: the Pacific states of the United States, Canada’s wheat belt, the pampas of Argentina, and the Mediterranean zone of Chile. The former absence of food production in these lands was due entirely to their local paucity of domesticable wild animals and plants, and to geographic and ecological barriers that prevented the crops and the few domestic animal species of other parts of the Americas from arriving. Those lands became productive not only for European settlers but also, in some cases, for Native Americans, as soon as Europeans introduced suitable domestic animals and crops. For instance, Native American societies became renowned for their mastery of horses, and in some cases of cattle and sheepherding, in parts of the Great Plains, the western United States, and the Argentine pampas. Those mounted plains warriors and Navajo sheepherders and weavers now figure prominently in white Americans’ image of American Indians, but the basis for that image was created only after 1492. These examples demonstrate that the sole missing ingredients required to sustain food production in large areas of the Americas were domestic animals and crops themselves.

  In those parts of the Americas that did support Native American agriculture, it was constrained by five major disadvantages vis-à-vis Eurasian agriculture: widespread dependence on protein-poor corn, instead of Eurasia’s diverse and protein-rich cereals; hand planting of individual seeds, instead of broadcast sowing; tilling by hand instead of plowing by animals, which enables one person to cultivate a much larger area, and which also permits cultivation of some fertile but tough soils and sods that are difficult to till by hand (such as those of the North American Great Plains); lack of animal manuring to increase soil fertility; and just human muscle power, instead of animal power, for agricultural tasks such as threshing, grinding, and irrigation. These differences suggest that Eurasian agriculture as of 1492 may have yielded on the average more calories and protein per person-hour of labor than Native American agriculture did.

  SUCH DIFFERENCES IN food production constituted a major ultimate cause of the disparities between Eurasian and Native American societies. Among the resulting proximate factors behind the conquest, the most important included differences in germs, technology, political organization, and writing. Of these, the one linked most directly to the differences in food production was germs. The infectious diseases that regularly visited crowded Eurasian societies, and to which many Eurasians consequently developed immune or genetic resistance, included all of history’s most lethal killers: smallpox, measles, influenza, plague, tuberculosis, typhus, cholera, malaria, and others. Against that grim list, the sole crowd infectious diseases that can be attributed with certainty to pre-Columbian Native American societies were nonsyphilitic treponemas. (As I explained in Chapter 11, it remains uncertain whether syphilis arose in Eurasia or in the Americas, and the claim that human tuberculosis was present in the Americas before Columbus is in my opinion unproven.)

  This continental difference in harmful germs resulted paradoxically from the difference in useful livestock. Most of the microbes responsible for the infectious diseases of crowded human societies evolved from very similar ancestral microbes causing infectious diseases of the domestic animals with which food producers began coming into daily close contact around 10,000 years ago. Eur
asia harbored many domestic animal species and hence developed many such microbes, while the Americas had very few of each. Other reasons why Native American societies evolved so few lethal microbes were that villages, which provide ideal breeding grounds for epidemic diseases, arose thousands of years later in the Americas than in Eurasia; and that the three regions of the New World supporting urban societies (the Andes, Mesoamerica, and the U.S. Southeast) were never connected by fast, high-volume trade on the scale that brought plague, influenza, and possibly smallpox to Europe from Asia. As a result, even malaria and yellow fever, the infectious diseases that eventually became major obstacles to European colonization of the American tropics, and that posed the biggest barrier to the construction of the Panama Canal, are not American diseases at all but are caused by microbes of Old World tropical origin, introduced to the Americas by Europeans.

  Rivaling germs as proximate factors behind Europe’s conquest of the Americas were the differences in all aspects of technology. These differences stemmed ultimately from Eurasia’s much longer history of densely populated, economically specialized, politically centralized, interacting and competing societies dependent on food production. Five areas of technology may be singled out:

  First, metals—initially copper, then bronze, and finally iron—were used for tools in all complex Eurasian societies as of 1492. In contrast, although copper, silver, gold, and alloys were used for ornaments in the Andes and some other parts of the Americas, stone and wood and bone were still the principal materials for tools in all Native American societies, which made only limited local use of copper tools.

  Second, military technology was far more potent in Eurasia than in the Americas. European weapons were steel swords, lances, and daggers, supplemented by small firearms and artillery, while body armor and helmets were also made of solid steel or else of chain mail. In place of steel, Native Americans used clubs and axes of stone or wood (occasionally copper in the Andes), slings, bows and arrows, and quilted armor, constituting much less effective protection and weaponry. In addition, Native American armies had no animals to oppose to horses, whose value for assaults and fast transport gave Europeans an overwhelming advantage until some Native American societies themselves adopted them.

  Third, Eurasian societies enjoyed a huge advantage in their sources of power to operate machines. The earliest advance over human muscle power was the use of animals—cattle, horses, and donkeys—to pull plows and to turn wheels for grinding grain, raising water, and irrigating or draining fields. Waterwheels appeared in Roman times and then proliferated, along with tidal mills and windmills, in the Middle Ages. Coupled to systems of geared wheels, those engines harnessing water and wind power were used not only to grind grain and move water but also to serve myriad manufacturing purposes, including crushing sugar, driving blast furnace bellows, grinding ores, making paper, polishing stone, pressing oil, producing salt, producing textiles, and sawing wood. It is conventional to define the Industrial Revolution arbitrarily as beginning with the harnessing of steam power in 18th-century England, but in fact an industrial revolution based on water and wind power had begun already in medieval times in many parts of Europe. As of 1492, all of those operations to which animal, water, and wind power were being applied in Eurasia were still being carried out by human muscle power in the Americas.

  Long before the wheel began to be used in power conversion in Eurasia, it had become the basis of most Eurasian land transport—not only for animal-drawn vehicles but also for human-powered wheelbarrows, which enabled one or more people, still using just human muscle power, to transport much greater weights than they could have otherwise. Wheels were also adopted in Eurasian pottery making and in clocks. None of those uses of the wheel was adopted in the Americas, where wheels are attested only in Mexican ceramic toys.

  The remaining area of technology to be mentioned is sea transport. Many Eurasian societies developed large sailing ships, some of them capable of sailing against the wind and crossing the ocean, equipped with sextants, magnetic compasses, sternpost rudders, and cannons. In capacity, speed, maneuverability, and seaworthiness, those Eurasian ships were far superior to the rafts that carried out trade between the New World’s most advanced societies, those of the Andes and Mesoamerica. Those rafts sailed with the wind along the Pacific coast. Pizarro’s ship easily ran down and captured such a raft on his first voyage toward Peru.

  IN ADDITION TO their germs and technology, Eurasian and Native American societies differed in their political organization. By late medieval or Renaissance times, most of Eurasia had come under the rule of organized states. Among these, the Habsburg, Ottoman, and Chinese states, the Mogul state of India, and the Mongol state at its peak in the 13th century started out as large polyglot amalgamations formed by the conquest of other states. For that reason they are generally referred to as empires. Many Eurasian states and empires had official religions that contributed to state cohesion, being invoked to legitimize the political leadership and to sanction wars against other peoples. Tribal and band societies in Eurasia were largely confined to the Arctic reindeer herders, the Siberian hunter-gatherers, and the hunter-gatherer enclaves in the Indian subcontinent and tropical Southeast Asia.

  The Americas had two empires, those of the Aztecs and Incas, which resembled their Eurasian counterparts in size, population, polyglot makeup, official religions, and origins in the conquest of smaller states. In the Americas those were the sole two political units capable of mobilizing resources for public works or war on the scale of many Eurasian states, whereas seven European states (Spain, Portugal, England, France, Holland, Sweden, and Denmark) had the resources to acquire American colonies between 1492 and 1666. The Americas also held many chiefdoms (some of them virtually small states) in tropical South America, Mesoamerica beyond Aztec rule, and the U.S. Southeast. The rest of the Americas was organized only at the tribal or band level.

  The last proximate factor to be discussed is writing. Most Eurasian states had literate bureaucracies, and in some a significant fraction of the populace other than bureaucrats was also literate. Writing empowered European societies by facilitating political administration and economic exchanges, motivating and guiding exploration and conquest, and making available a range of information and human experience extending into remote places and times. In contrast, use of writing in the Americas was confined to the elite in a small area of Mesoamerica. The Inca Empire employed an accounting system and mnemonic device based on knots (termed quipu), but it could not have approached writing as a vehicle for transmitting detailed information.

  THUS, EURASIAN SOCIETIES in the time of Columbus enjoyed big advantages over Native American societies in food production, germs, technology (including weapons), political organization, and writing. These were the main factors tipping the outcome of the post-Columbian collisions. But those differences as of A.D. 1492 represent just one snapshot of historical trajectories that had extended over at least 13,000 years in the Americas, and over a much longer time in Eurasia. For the Americas, in particular, the 1492 snapshot captures the end of the independent trajectory of Native Americans. Let us now trace out the earlier stages of those trajectories.

  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 co
mmon 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.