Explaining variation in hunter-gatherer livelihoods hinges on our ability to predict the tradeoffs and opportunities of pursuing different kinds of prey. Central to this problem is the commonly held assumption that larger animals provide higher returns upon encounter than smaller ones. However, to test this assumption, actualistic observations of hunting payoffs must be comparable across different social, technological, and ecological contexts. In this meta-analysis, we revisit published and unpublished estimates of prey return rates (n = 217 from 181 prey types) to assess, first, whether they are methodologically comparable, and second, whether they correlate with body size. We find systematic inter-study differences in how carcass yield, energetic content, and foraging returns are calculated. We correct for these inconsistencies first by calculating new estimates of energetic yield (kcals per kg live weight) and processing costs for over 300 species of terrestrial and avian game. We then recalculate on-encounter returns using a standardized formula. We find that body size is a poor predictor of on-encounter return rate, while prey characteristics and behavior, mode of procurement, and hunting technology are better predictors. Although prey body size correlates well with processing costs and edibility, relationships with pursuit time and energetic value per kilogram are relatively weak.
All Science Journal Classification (ASJC) codes