Acknowledgments
This research was supported by Critical Ecosystem Partnership Fund (CEPF). NS was supported by the Royal Golden
Jubilee Ph.D. Program, Thailand (PHD/0105/2553). We are grateful to Mr. Tran Van Thanh who currently is the chief of
Yok Don National Park for allowing us to conduct research in Cat Tien and Yok Don National Parks. Special thanks to the
following people for their help with fieldwork: Nguyen Tran Vy, G.A. Gale, T. Ong-in, D. Khamcha, J. Suwannarat, Le Van
Thuaand Truong Van Ty. We also thank G.A. Gale, D. Ngoprasert, W. Chutipong and N. Tantipisanuh for much help on data
analysis. Thanks to S.J. Brown, P.D. Round, S. Dowell and G.A. Gale for their constructive comments on a draft of this paper.