1. Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa
2. Department of Biological Sciences, School of Life and Environmental Sciences, Royal Holloway University of London, Egham Hill, Egham, Surrey TW20 0EX, UK
3. Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa