1. Department of Animal Science, University of Namibia, Windhoek, Namibia.
2. Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa.
3. South African Research Chair of Behavioural Ecology and Physiology, Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa.