About the Authors

Erik Meijaard


Affiliations People and Nature Consulting International, Jakarta, Indonesia, School of Archaeology and Anthropology, Australian National University, Canberra, Australian Capital Territory, Australia

Alan Welsh

Affiliation Centre for Mathematics and its Applications, Mathematical Sciences Institute, Australian National University, Canberra, Australian Capital Territory, Australia

Marc Ancrenaz

Affiliation Kinabatangan Orangutan Conservation Project, Sandakan, Sabah, Malaysia

Serge Wich

Affiliations Anthropological Institute & Museum, University of Zurich, Zurich, Switzerland, Sumatran Orangutan Conservation Programme (PanEco-YEL), Medan, Sumatra, Indonesia

Vincent Nijman

Affiliations Zoological Museum Amsterdam, Amsterdam, The Netherlands, Department of Anthropology and Geography, School of Social Sciences and Law, Oxford Brookes University, Headington, Oxford, United Kingdom

Andrew J. Marshall

Affiliation Department of Anthropology, Graduate Group in Ecology and Animal Behavior Graduate Group, University of California Davis, Davis, California, United States of America

Competing Interests

The first author is a freelance consultant working through a consultancy company. The company has no financial interests in this study and has had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The first author's affiliation with People and Nature Consulting International does not alter his adherence to all the PLoS ONE policies on sharing data and materials.

Author Contributions

Conceived and designed the experiments: EM MA. Performed the experiments: EM AW SW VN. Analyzed the data: EM AW MA SW AJM. Contributed reagents/materials/analysis tools: EM AJM. Wrote the paper: EM AW MA SW VN AJM.