THE TRANSITION FROM A MOBILE HUNTER GATHERER LIFEWAY TO A MORE SEDENTARY EARLY FARMING LIFEWAY AT LAS CHACHALACAS IN SONORA, MEXICO

Abstract

This thesis explores how the occupants of Las Chachalacas, an archaeological site in Sonora, Mexico transitioned from a mobile hunter gatherer lifeway to a more sedentary early farming lifeway. Using analysis of the lithic assemblage and theoretical frameworks drawn from Binford’s New Archaeology as well as Human Behavioral Ecology, this study investigates changes in mobility and subsistence strategies. Las Chachalacas was intermittently occupied from the Late Paleoindian through the Early Agricultural period. Analysis of the chipped stone artifacts, including bifacial cores, tool flakes, and debitage, suggests a shift from residential mobility to logistical mobility. This pattern reflects longer-term occupation at centralized base camps, with specialized forays into the surrounding landscape to acquire resources. The presence of non-local lithic material supports this interpretation. Ground stone artifacts, particularly manos and metates, are used to evaluate subsistence patterns. The dominance of flat/concave metates and small one-handed manos, along with botanical evidence of small-seed use (e.g., chenopodium and amaranth), suggests emerging farming practices, though not yet intensive. The limited presence of basin metates and minimally worn tools indicates early plant processing rather than more intensive farming. Comparative data from related sites such as La Playa, Los Pozos, Las Capas, and Cerro Juanaqueña place Las Chachalacas within a broader regional trend of increasing sedentism and plant cultivation. Ultimately, the evidence supports the interpretation of Las Chachalacas as a seasonal base camp used by groups transitioning toward an early farming lifestyle within a logistical mobility framework