In 1835, the Chatham Islands, near New Zealand, were invaded by the Maori tribe, armed with guns and axes. The Maori murdered the Moriori, who lived on the Chatham Island. Although the Maori and the Moriori peoples had lived close beside one another for thousands of years, their societies had clearly branched off in different directions. The Moriori were hunter-gatherers, while the Maori turned to farming. Diamond will try to understand why the Maori pursued farming.
The chapter begins with another example of a clash between civilizations (similar to the descriptions of how Europeans brutally colonized the New World after 1492). Of course, civilizations interact with one another in many different ways, some of them peaceful. But military clashes are a particularly clear illustration of one civilizations’ real-world “superiority” to another.
In Polynesia (the part of the world that includes the Chatham Islands), there are thousands of islands, each with a different climate and elevation. Flora and fauna on these islands are incredibly diverse, reflecting the environment differences between islands. Yet the islands were colonized at approximately the same time by a group of nomadic hunter-gatherers who looked alike and spoke the same language. Therefore, Polynesia is a good “case study” for why environmental factors lead societies to branch off in different directions.
By analyzing the data, Diamond conducts something like an “experiment.” As in any experiment, Diamond isolates a “dependent variable”—the people who came to Polynesia—and sets it equal for each of his case studies (i.e., the people who colonized the different Polynesian islands had the same culture and almost identical genetic makeup, at least to begin with). In this way, Diamond can study the influence of an independent variable—geography—on the dependent variable—the people and societies of Polynesia.
The Moriori embraced a hunter-gatherer culture on their island because their island couldn’t support crops of any kind—the climate was too cold. Also, the Chatham Islands, where the Moriori lived, were tiny, capable of supporting only a few thousand people. The Moriori renounced warfare and agreed to cooperate. There were no strong government structures, and only the simplest of weapons. In the Maori islands of Polynesia, however, there was a warm, moist climate, good for growing crops. There were about 100,000 Maori on the islands, and they fought amongst themselves for control of crops. The result was that when the Maori met the Moriori, the Maori slaughtered the Moriori in a few days.
In the simplest terms, the passage illustrates a connection between society and geography. Certain climates and the presence of certain resources predispose a group of people to set up a certain kind of society—here, for example, the climate and size of the Maori islands predispose the Maori people to be more violent and have more agriculture.
The nomads who came to Polynesia thousands of years ago had the same culture and language, but they all adapted to the environments of the various islands where they settled. Diamond then breaks “environment” up into categories: climate, geological activity, “marina” (i.e., the flora, fauna, and geographic structures found around an island’s coast), area, terrain fragmentation, and isolation (i.e., proximity to other environments). For each category, environmental differences between islands cause societal differences. For example, moist, warm climates favor agriculture, since crops grow easily. Volcanic activity in Polynesia (i.e., a form of geological activity) produces hard, shiny stones that can be used to make tools. Certain Polynesian islands have rocky coasts, meaning that people who lived there had no way of obtaining fish (marina).
The nomadic people who Polynesians were once virtually identical—with the same culture and language. But geography is such an important determinant of society that it changed this homogenous culture into many extremely diverse peoples. Polynesians adapted to their surroundings, just as their Homo sapiens ancestors did, by making use of available resources, such as soil, rock, fish, etc. As we saw with the Maori, certain of these resources lend themselves to warfare and military supremacy.
Environmental differences between Polynesian islands partly explain differences in subsistence. The nomads who came to Polynesia brought pigs, dogs, and chickens with them to their islands. The people of Easter Island brought only chickens. Because they didn’t have access to coral reefs or shallow waters, they had no ways of fishing, and therefore, they built big chicken houses for poultry farming. The Easter Islanders adapted to their environments. Meanwhile, other islanders, such as the people of Tonga and Anuta, adapted to their warm environments by developing agricultural techniques for the cultivation of taro, a hearty crop.
One important way to classify the different Polynesian societies is by their methods of food production. Here, very clearly, the Polynesians adapt to their surroundings—making use of livestock, fruits, game, etc. Agriculture is a particularly significant form of food production, as we’ll see, but for now it’s important to note that agriculture is only available to certain Polynesian societies—other societies couldn’t establish agriculture even if they wanted to do so, because of the geography of their surroundings.
Another way to classify the different civilizations in Polynesia is by population density. The Chatham peoples, who were hunter-gatherers, only had about 5 people per square mile, while on the other end, the agriculturalists of Anuta had about 1,100 people per square mile. Dense agricultural societies tended to have much more diverse societies, with many different professions, more complex technologies, and elaborate political organizations. The Hawaiian Islands are a textbook example of a dense, agricultural society: before Europeans colonized Hawaii, Hawaiian society had extensive agriculture and eight distinct levels of society.
There seems to be a direct correlation between population density and extensiveness of agriculture—the communities with large-scale, complex agricultural practice tend to be dense and large, reflecting, perhaps, the greater food yield per square mile of agricultural societies (when compared with the food yield for hunter-gatherer communities).
Political structures in Polynesia became more complex as society became denser and resources became more plentiful. On the Chatham Islands, where the population was small and there were few plentiful resources, decisions were reached by a simple group consensus. But in Hawaii or Tonga, there were hereditary chiefs who decided how land and food would be divided up and who gave messages that had to be passed down the chain of command.
At this point, Diamond deals with correlation, not causation—i.e., he notes that agricultural production and population density seem to have some positive relationship with the establishment of complex social structures, but he doesn’t yet explain what this relationship consists of—or which factor causes which.
The Polynesians also made different kinds of artifacts, based on the resources available. On the Chathams, houses were very small and simple, and the people used few tools, reflecting the absence of resources like volcanic rock or metal. In Tonga or the Marquesas, where the population density was higher and more natural resources were available, there were more elaborate, even monumental buildings, and complex tools.
Diamond notes a correlation between agriculture, organization, and technology, but does not yet break down what this correlation consists of. Nevertheless, it’s clear that certain societies in Polynesia were, in a word, “lucky” to have access to metal and rock—their access to these resources gave them a military advantage.
Polynesia, Diamond concludes, is a good example of how huge societal differences arise from environmental differences. The question becomes—can we generalize our findings from Polynesia to the rest of the world?
Diamond will try to generalize his findings in Polynesia to the rest of the world. (It’s worth noting that Diamond’s project bears a striking resemblance to that of the scientist Charles Darwin—who began by studying natural selection on the tiny, isolated Galapagos Islands, and later generalized his findings about environmental adaptation to all life forms.)