1. Animal Behaviour and Cognition, Department of Biology Utrecht University Utrecht The Netherlands
2. c/o Sabah Wildlife Department Danau Girang Field Centre Kota Kinabalu Sabah Malaysia
3. Organisms and Environment Division, School of Biosciences Cardiff University Cardiff UK
4. Sabah Wildlife Department Kota Kinabalu Sabah Malaysia
5. Animal Science Department Biomedical Primate Research Centre Rijswijk The Netherlands
6. Kenderdine Maths and Statistics Bowral New South Wales Australia
7. Wilder Institute/Calgary Zoo Calgary Alberta Canada