<p>Archaeological research on the Shivwits Plateau, northwestern Arizona, suggests that the Ancestral Puebloan inhabitants of that area engaged in both hide processing and the heat treatment of calcareous stones. This paper proposes a connection between these two activities, arguing that (at least some of) the heated rocks were transformed into lime for use in hide preparation. We suggest that the decision to use lime was influenced by local social and environmental conditions, and arose from an intimate familiarity with the landscape and a sophisticated understanding of lime, hides, and pathogens. Once adopted, however, this practice would have provided several benefits. Specifically, experimental results show that soaking hides in a lime solution, compared to plain water, significantly reduces bacterial growth—including pathogens—by several orders of magnitude, and decreases dehairing time by more than fivefold. We argue that these health and time-saving advantages would have been particularly valuable given the logistical challenges faced by the Shivwits Plateau people in hide processing, and that the Ancestral Puebloan people, drawing on generations of Indigenous scientific knowledge, would have keenly understood them.</p>