1. Animal Health & Behavior, Distance Education, Unity Environmental University, New Gloucester, ME, USA
2. Department of Animal & Rangeland Sciences, Oregon State University, Corvallis, OR, USA
3. Department of Psychology, Graduate School of Letters, Kyoto University, Kyoto, Japan
4. Japan Society for the Promotion of Science, Kojimachi Business Center Building, Tokyo, Japan
5. Department of Animal Science and Biotechnology, Azabu University, Kanagawa, Japan
6. Wildlife Research Center, Kyoto University, Kyoto, Japan
7. Research and Development Section, Anicom Speciality Medical Institute Inc., Yokohama, Japan
8. Department of Comparative and Developmental Psychology, Graduate School of Human Sciences, Osaka University, Osaka, Japan