Abstract
The replacement of the atlatl and dart by the bow and arrow marks a major technological transformation in the human past, yet the timing and dynamics of this transition in North America remain poorly resolved due to the poor preservation of organic weaponry. Here, we compile and analyze a dataset of 140 radiocarbon dates from 136 well-preserved organic weapons recovered from western North America, spanning approximately the last 10,000 years. Using chronological modeling, optimal linear estimation, and Bayesian logistic regression, we show that bow technology first appears in both northern and southern regions around 1,400 years before present. The dynamics of adoption, however, differ sharply by region. In the south, across a vast area from northern Mexico to California and the Southwest, the bow rapidly and almost completely replaces the atlatl, a case of technological disruption in which an innovation decisively renders an older system obsolete. In the north, in contrast, the bow and atlatl coexisted for more than a millennium. This coexistence reflects a broader global pattern of increasing technological richness at higher latitudes, where ecological risk is mitigated through diversification rather than specialization. Our findings clarify previous claims of much earlier bow use in North America, demonstrate the importance of rare invention events followed by rapid diffusion, and highlight the contingent pathways by which technologies are adopted or abandoned. These results provide insight into the processes of technological evolution, showing how innovation, ecology, and cultural transmission interact to shape long-term human history.