A recent study led by Robert Kelly, professor emeritus of archaeology at the University of Wyoming, sheds light on the population dynamics of North America's Indigenous communities before European contact. The research, published in the Proceedings of the National Academy of Sciences (PNAS), utilized radiocarbon data from the past 2,000 years to track changes in population size.
The study found that while Indigenous populations varied across regions, there was a continent-wide peak around 1150 A.D., followed by declines attributed to factors such as drought, disease, emigration, and warfare. Erick Robinson, Associate Research Professor at DRI and co-author of the study, emphasized the significance of radiocarbon ages as indirect measurements for past human population growth. He stated: “Aggregations of radiocarbon ages provide the most powerful indirect ‘proxy’ measurement for past human population growth.”
Kelly's team analyzed radiocarbon records from 18 major watersheds and observed regional differences in population trends. For instance, interior regions saw declines between 1080 and 1300 A.D., whereas populations in areas like the Great Lakes and California remained stable until after European arrival.
“Europeans unknowingly arrived at a time when Indigenous populations had already declined,” Kelly noted. He suggested that earlier European contact might have encountered larger societies capable of stronger resistance.
Migration played a role in these demographic shifts. For example, people moved from Cahokia to areas along the Ohio River and into Tennessee. However, migration alone did not account for all population losses. The researchers pointed out that while European contact had severe impacts on Indigenous peoples, their numbers did not simply peak in 1500 A.D. and then decline.
Previous studies linked pre-contact declines around 1150 A.D. to disease but were limited by smaller datasets biased towards northern states. In contrast, Kelly's research used an updated Canadian Archaeological Radiocarbon Database (CARD) for more accurate analysis.
The study also dispels colonialist notions that pre-Columbian declines signified a "dying race," instead highlighting natural cycles of growth and migration experienced by all human societies.
Other contributors to this research include Madeline Mackie from Michigan State University; Spencer Pelton, Wyoming State Archaeologist; and Erick Robinson from Desert Research Institute in Reno.
For further information about this study or Robert Kelly’s work on archaeology since 1973 across various U.S. states and Chile, he can be contacted via email at rlkelly@uwyo.edu.