The authors would like to thank all the institutions and people that somehow contributed to make this project possible:
To the funding institutions/grants: European Commission Leonardo da Vinci grant, Center for Systems Neuroscience Hannover, Forschungszentrum Jülich, Gesellschaft der Freunde der TiHo, University of Veterinary Medicine Hannover;
To the institutions where the data collection took place: Apenheul Primate Park (The Netherlands), Leipzig Zoological Garden (Germany), Sepilok Rehabilitation Centre (Malaysia), Tierpark Carl Hagenbeck (Germany) and Zoo Wilhelma (Germany);
To the people who assisted in collecting part of the audio-visual material: C. Schopf, E. Ey, M. Wessels, S. Johnson;
To the people that sent additional photographs: C. Rodrigues, F. Lasmana, N. Baptista, R. Sharma;
To collaborators that were involved on the reliability assessment: M. Lembeck and P. Kuchenbuch;
To the institutions that established a mobility partnership acting as host/sending organizations: Faculty of Sciences of the University of Lisbon and University of Portsmouth.