Affiliation: | 1. Max Planck Institute for Evolutionary Anthropology, Department of Primatology, Leipzig, Germany;2. Martin Surbeck, Max Planck Institute for Evolutionary Anthropology, Department of Primatology, Deutscher Platz 6, 04103 Leipzig, Germany.;3. Ta? Chimpanzee Project, Centre Suisse de Recherches Scientifiques, Abidjan, Ivory Coast |