1. Department of Zoology; University of Cambridge; Downing Street Cambridge CB2 3EJ UK
2. Department of Mathematical and Statistical Sciences; Department of Biological Sciences; University of Alberta; Edmonton AB T6G 2G1 Canada
3. Kalahari Meerkat Project; Kuruman River Reserve; Northern Cape South Africa
4. Institute of Evolutionary Biology and Environmental Studies; University of Zurich; Winterthurerstrasse 190 CH-8057 Zurich Switzerland