1. UMR 7179 CNRS/MNHN, 57 rue Cuvier, Case postale, Paris Cedex 5, France
2. Behavioural Ecology & Sociobiology Unit, German Primate Centre, Leibniz Institute for Primate Research, Kellnerweg, Göttingen, Germany
3. Department of Life Sciences, The Natural History Museum, London, UK
4. Georg-August-Universität Göttingen, Faculty of Economic Sciences, Chair of Statistics, Humboldtallee, Göttingen, Germany
5. HEC Liège, University of Liège, 14 rue Louvrex, Liège, Belgium
6. Department of Evolutionary Anthropology, Duke University, Durham, USA