Reply to : Accurate population proxies do not exist between 11.7 and 15 ka in North America

Abstract

In a recent study we used a novel statistical approach to investigate whether Late Quaternary changes in North American megafauna populations correlated with changes in human population densities (as is predicted by most “overkill” hypotheses), climate change, or both. Following the design of a recent study by Broughton and Weitzel and using their datasets, we found no relationship between human and megafauna population levels. We did, however, find a significant positive relationship between megafauna population levels and climate change, suggesting that climate change played a key role in the demise of North America’s megafauna. Pelton et al. claim that the datasets and analyses used in our study are not “robust enough to support [our] conclusions.” We agree that the North American archaeological and palaeontological records are far from perfect—a point we emphasize in our article—and we welcome the opportunity here to clarify some of the points presented by Pelton and colleagues as well as provide additional analyses that support our original findings.