What is it about?
We used tens of thousands of radiocarbon dates to track changes in the Indigenous population over the last 2000 years. We found that the continent’s population reached a peak about AD 1150, and the declined dramatically until about AD 1400, when it stabilized before declining again after AD 1500. The declined dramatically until did not happen at the same time, however. It began in the central Rocky Mountains, then throughout the center of the US. The west coast (California, Oregon, Washington and Idaho) and the northeast (the Great Lakes, New England, and the mid-Atlantic) did not decline until after contact. The causes are a combination of climate change that affected the food supply and consequently human fertility and child mortality, disease in large settlements that formed in many places after about AD 900, and warfare, as populations moved to avoid climate-induced drought.
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Photo by Richard Hedrick on Unsplash
Why is it important?
Our work replicates a conclusion reached by other researchers in 2010 working with a smaller, lower quality database. With more data, we add how the process of the population decline played out across space. We were also able to rule out other factors that might affect radiocarbon date samples to realistically track population growth and decline.
Perspectives
This project actually began in 2014, when we began collecting radiocarbon dates from the published literature; it took until 2021 to complete this effort. Although there are many things that can be done with our database, which is freely available to vetted researchers through the Canadian Radiocarbon Archaeological Database, examining this pre-European contact decline was a major goal.
Robert Kelly
University of Wyoming
Read the Original
This page is a summary of: Spatiotemporal distribution of the North American Indigenous population prior to European contact, Proceedings of the National Academy of Sciences, February 2025, Proceedings of the National Academy of Sciences,
DOI: 10.1073/pnas.2419454122.
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