The formative period (1,500 B.C. -A. D. 500) in the lower Azapa Valley in northwest Chile represents a major shift in subsistence strategies in the Atacama Desert, as coastal groups adopted agriculture and moved deeper into the valley. Frequencies of caries and antemortem tooth loss were compared between site locations (coast vs. valley) and by archaeological phase (early vs. late) to interpret the degree to which these incipient agriculturalists were reliant on domesticated resources. Residents of the interior valley exhibited significantly more oral pathology than those along the coast. The results identify that although the Formative period residents of the lower Azapa Valley practiced a mixed subsistence strategy, the degree of reliance on agricultural production differed between the coast and the valley. Ecological models are used to suggest that these patterns are likely tied to local investment, adaptive cycles and niche construction.
