Guns, Germs, and Steel: Chapter 8 Summary & Analysis

Given what we’ve learned about domesticated plants, there are two major obstacles to the development of agriculture: 1) humans are unwilling to experiment with domestication practices, and 2) there aren’t enough wild plants to experiment with. Diamond will focus largely on the second obstacle.

While there are millions of plants around the world, a surprisingly small number of them are suitable for domestication: most plants produce no fruit, and their leaves or roots are inedible. In modern times, humans haven’t succeeded in domesticating a single new plant: our ancestors worked out which crops were edible and which weren’t. Even so, crops have been domesticated in some places but not others. Some African peoples domesticated the plant sorghum, but others did not. Some peoples have access to figs and olives and domesticated both, and others had the same access, but did not domesticate them.

The problem is that hunter-gatherer societies gradually became agricultural societies if and only if there were many available crops that could be domesticated, not just two or three. How, then, do archaeologists assess which areas of the ancient world were “suitable” for domestication, and which areas had too few crops to make agriculture practical? Diamond will try to answer his own question by examining three different regions: Mesopotamia, New Guinea, and the eastern U.S.

Mesopotamia, or the Fertile Crescent, had some important environmental advantages for early agriculturalists. The climate favored annuals, i.e., crops that sprout once a year. Annuals tend to be “mostly” edible:, a large percentage of their total mass can be consumed safely (whereas, say, a cherry tree, is almost entirely inedible—only the cherries themselves can be eaten). Mesopotamia also contained many hermaphroditic self-pollinating crops; i.e., crops that could reproduce on their own and didn’t require farmers to carefully cross-pollinate seeds every year. These crops were also protein-heavy, meaning that they could nourish human beings.

A large chunk of the world’s annual hermaphroditic crops—the crops that are easiest for farmers to domesticate and grow—are from the Fertile Crescent. Australia has a similar climate to the Fertile Crescent, but not many seeds; the same is true of Chile, California, and Southern Africa. The Fertile Crescent was the site of the earliest human agriculture because it held the greatest number of different species of plants that could be domesticated and farmed efficiently.

In early Mesopotamian civilization, people could rely on many different sources of nutrition: carbohydrates from wheat and other cereal grains, fiber and oil from flax, and protein and dairy from domesticated animals like sheep and cows (see the next chapter). With the tools of agriculture, the Fertile Crescent could produce enough nutrition to support human life.

Diamond notes that so far, he’s talked about why agriculture succeeded first in Mesopotamia without ever once alluding to any superiorities in Mesopotamian people. His subject is the environment, and its influence on human beings. Nevertheless, Diamond’s ideas rest upon an assumption: the ancient societies of the world had near-perfect knowledge of their environments’ plants and animals. Millennia ago, nearly all human beings had a vast knowledge of plants—which ones were poisonous, which could be planted easily, etc. Therefore, it is highly unlikely that early farmers could have ignored a wild species with potential value to them.

Now Diamond will contrast Mesopotamia with the eastern U.S. and New Guinea. In New Guinea, there were many reasons to pursue agriculture—there was almost no big game to hunt, for example. Agriculture developed in New Guinea around 7000 B.C., with farmers cultivating sugarcane, bananas, taro, and yams. While such crops nourished the New Guineans, there were no grains available. Also, there were no large mammals available for domestication to help with the farming (as there were in Mesopotamia). So while agriculture in New Guinea provided nutrition, it didn’t provide all the necessary nutrients.

In the eastern United States, agriculture arose around 2000 B.C.: farmers domesticated squash, sunflowers, sumpweed, and goosefoot (similar to spinach), and later knotweed, maygrass, and “little barley.” Native American crops were extremely nutritious, high in protein and oil. And yet there were major problems with the Native Americans’ diet. Sumpweed causes hay fever and skin irritation. Also, goosefoot and little barley have tiny seeds, which make them unreliable as crops—a storm could destroy them. So even though the eastern U.S. had a good climate for agriculture, it wasn’t enough: the absence of resilient crops with big seeds, annuals, and hermaphroditic self-pollinators resulted in limited agriculture.

The chapter ends with some caveats. First, people don’t necessarily accept better crops and livestock just because they’re more nutritious. Just because Mesopotamia had lots of useful crops available doesn’t automatically mean that it was going to foster agriculture. Still, in the long run, Mesopotamia was far more likely to develop sophisticated agriculture than either New Guinea or the eastern U.S.—and it did, sooner. Also, the “stages” of domestication that Diamond outlines (first easy annual crops like wheat, then figs and olives, etc.) aren’t set in stone. Still, civilizations will tend to go about domestication of crops in such an order (essentially, easy to difficult).