About the Authors
Laboratory of Human Evolutionary Studies, Department of Archaeology, Simon Fraser University, Burnaby, British Columbia, Canada
Department of Anthropology, University of Western Ontario, London, Canada
The authors have declared that no competing interests exist.
Conceived and designed the experiments: AC. Performed the experiments: AC. Analyzed the data: AC MC AN. Contributed reagents/materials/analysis tools: AC. Wrote the paper: AC MC AN.