1. Department of Zoology, University of Wuppertal, 42119 Wuppertal, Germany
2. Zoo Wuppertal, 42117 Wuppertal, Germany
3. Endocrinology Laboratory, German Primate Centre, 37077 Goettingen, Germany
4. Zoological Garden Halle, 06114 Halle (Saale), Germany
5. Serengeti-Park Department of Research, Serengeti-Park Hodenhagen, 29693 Hodenhagen, Germany
6. Zoo Karlsruhe, 76137 Karlsruhe, Germany
7. Department of Ecology, Europa-Universität Flensburg, 24943 Flensburg, Germany