About the Authors
Department of Biological Sciences and Department of Neurology and Neurological Sciences, Stanford University, Stanford, California, United States of America
Institute of Primate Research, National Museums of Kenya Karen, Nairobi, Kenya
The authors have declared that no conflicts of interest exist.
RMS and LJS conceived, designed, and performed the experiments. RMS analyzed the data and contributed reagents/materials/analysis tools. RMS and LJS wrote the paper.