Colonization of the Americas: Disease Ecology and the Paleoindian Lifestyle

The disease barrier hypothesis is one long-standing explanation of the temporal discrepancies between the initial colonization of North and South America. The model postulates an epidemiological barrier that prohibited or slowed the initial migration into South America during the Late Pleistocene. Using data from ethnographically documented hunter–gatherers, the theoretical foundations of the hypothesis are explored. In addition, likely demographic effects to colonizing populations are postulated and compared to disease-response mechanisms in foraging societies. Based on identified disease conditions deemed necessary to maintain a prohibitive barrier, it is suggested that disease transmission rates in the initial colonizing populations of the New World were likely extremely limited and insufficient to support the disease barrier concept.