November 18, 2006


Charles Mann's book summarizing recent research into life in the pre-Columbian Western Hemisphere is quite interesting, although a little slippery. His main theme is how enormous the population of the Americas was before the epidemics introduced by the Conquest, but he tends to slide back and forth between whether he's talking about America north or south of the Rio Grande. For example, he talks a lot about Cahokia, or Monks' Mound, near St. Louis, which had a population of about 15,000 around 1000 AD, before falling apart a couple of centuries before Columbus. But this appears to have been just about the only sizable urban center north of the Rio Grande, which raises questions in my mind about just how densely populated the future U.S. was. If it was densely populated, why was it so little urbanized, especially compared to the enormous number of cities in what's now Latin America? There are a lot of dirt mounds in Midwest, but as tourist attractions, they are lacking compared to what you can see in Latin America.

Perhaps the problem was that corn was a rather late arrival in the future US from its origin spot in Mexico, and urbanization would have followed. Or perhaps, North American Indians just didn't see much point to building big cities and future tourist attractions.

The urbanization of Mesoamerica and the northern half of South America was quite high. We're all familiar with a handful of well-visited monumental ruins like Chichen Itza, the huge pyramids outside of Mexico City, or Machu Pichu, but there are countless others. Something that Mann doesn't quite realize is that urban life was more feasible in the New World than in the Old World precisely because of the lack of contagious diseases that was the downfall of the New World when the Spaniards arrived bearing Old World germs into a region with no immunity. In the Old World until late in the 19th Century, cities were typically "demographic sinks" where the death rate was higher than the birth rate due to infectious diseases. Cities had to be constantly replenished with newcomers from the healthier countryside or they would disappear.

The disease burden was particularly severe in Africa, which is a major reason why Africa is so lacking in monumental ruins. I would bet that Guatemala alone has an order of magnitude more ruins of impressive scale than all of sub-Saharan Africa. In Africa, when the population density got too high, diseases would wipe out the populace, which is a big reason why Africa was thinly populated until recently. This doesn't appear to have been anywhere near as severe a problem in tropical America, presumably because Indians didn't bring many disease with them from Siberia, and because they had so few domesticated animals to pick up germs from.

My published articles are archived at -- Steve Sailer

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