Prey spatial structure and behavior affect archaeological tests of optimal foraging models: Examples from the Emeryville Shellmound vertebrate fauna

Foraging theory is increasingly used as a framework to analyze prehistoric resource depression, or declines in prey capture rates that stem from the activities of foragers. Resource depression, with the resulting declines in foraging efficiency, appears to be an important variable underlying many behavioral transitions in human prehistory. And, while two of the primary lines of evidence used to document resource depression archaeologically are temporal declines in the relative abundances of 'high-return' species and the mean age of harvested prey, this phenomenon may also be reflected by increases in both high-ranked prey abundances and mean age. These divergent signals are linked to variation in the behavior and spatial distributions of different prey species and are illustrated with the Emeryville Shellmound faunal sequence. More detailed attention should be given to these variables in applications of foraging models to the archaeological record.