In the Los Angeles Times, Jim Rossi reviews the new book claiming that the Americas were hugely populated before Columbus arrived with Afro-Eurasian diseases:
THINK back to high school history class: Remember the part about buffalo in the New World? It probably went something like this: When Europeans began settling the interior of North America in the 17th century, they encountered pristine forests and a vast prairie crowded with millions of the giant horned mammals along with countless other animals and birds. Over the next three centuries, desperate colonists, industrious frontiersmen and heedless sportsmen upset the natural balance, hunting the bison to the brink of extinction.
But like much of what we learned in school, that's not the whole story, Charles C. Mann tells us in his book "1491." "The Americas seen by the first colonists were teeming with game … [but] the continents had not been that way for long," Mann writes.
Many archeologists and anthropologists now believe, Mann says, that more people inhabited the Americas than lived in Europe at the time Christopher Columbus reached the New World in 1492...
Hepatitis, measles, cholera and smallpox preceded colonists into the interior of the New World, as native traders and messengers inadvertently transmitted a holocaust back to their homelands.
Genetically speaking, American Indians are believed to be descendants of relatively small groups that arrived from Asia, probably more than 20,000 years ago. They were less genetically diverse and suffered from fewer infectious diseases than Europeans. The conquistadors had immunities to Old World infectious diseases, but not to New World germs, such as syphilis; still, many more Europeans survived the encounter than did Indians.
These first explorers saw a continent in convulsive change. "Hernando De Soto's expedition staggered through the Southeast for four years in the early sixteenth century and saw hordes of people" lining the Mississippi River, Mann writes. A century later, Sieur Robert Cavelier de La Salle canoed down the same stretch of river and found "solitude unrelieved by the faintest trace of man," according to 19th century historian Francis Parkman. De Soto didn't see buffalo, but La Salle found them everywhere, filling the ecological void left by the missing people. "That's one reason whites think of Indians as nomadic hunters," UCLA anthropologist Russell Thornton tells Mann. "Everything else — all the heavily populated urbanized societies — was wiped out."
Mann makes the important point that Indians used techniques such as setting brush fires to revamp the landscape to their own specifications.
I'm skeptical, though, about just how many people ever lived in North America north of Mexico before Columbus. Mexico, Guatemala, and Peru feature Indian ruins of colossal scale, which are almost wholly lacking in the larger expanse of the U.S. Sure, there are the cliffdwellers of the Southwest and there are a bunch of dirt mounds in the Midwest, but many of the cultures that created the interesting bits of ruins in the U.S. collapsed before Columbus. For example, Cahokia near St. Louis had 15,000 to 20,000 inhabitants at one point, but was gone by 1300. I suspect that North American Indians lacked the agricultural technology to support large populations without eventual ecological collapse. Where are the Indian cities in the U.S. that collapsed after 1492?