1. Department for Primatology; Max Planck Institute for Evolutionary Anthropology; Deutscher Platz 6 04103 Leipzig Germany
2. Centre for Research and Conservation; Royal Zoological Society of Antwerp; K. Astridplein 26 2018 Antwerp Belgium
3. Behavioral Ecology and Ecophysiology; Department of Biology; University of Antwerp; Universiteitsplein 1 2610 Wilrijk Belgium