Abstract
Using direct observations and camera traps at eight sites across Indonesian Borneo we show how red langurs (Presbytis rubicunda) are more terrestrial than previously believed, regularly coming to the ground. This unusual behavior has been found at six of the eight sites surveyed. We find that red langurs come to the ground more frequently in disturbed forests, specifically ones which have been impacted by logging, fire, and hunting, though more data are needed to confirm this as a direct correlation. We also found a trend towards decreased ground use with increased elevation of the habitat. When on the ground, red langurs are predominantly engaged in feeding (50% direct observations, 61% camera traps) and traveling (29% direct observations, 13% camera traps). Red langurs are found on the ground throughout the day, at similar times to activity periods of the apex predator, the Sunda clouded leopard (Neofelis diardi). We suggest that ground use by red langurs could be an adaptation to disturbed forest to exploit additional food sources and to facilitate travel.
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09 August 2018
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Acknowledgements
This project involved collaboration between Borneo Nature Foundation and many individuals, organizations and universities. For logistical support and permits we thank Balai Lingkungan Hidup in Purak Cahu, Pak Herry Mulyadi Tuwan, Pak Purwanto and Pak Agusdin, The Nature Conservancy, Yayorin and the Bupati of Lamandau Regency. For their research collaboration, we thank the BRINCC team, Stan Lhota and Gabriella Fredriksson, the Centre for the International Cooperation in Management of Tropical Peatlands (CIMTROP), University of Palangka Raya and the Indonesian Ministry of Science and Technology (RISTEK) and Director General of Nature Conservation (PHKA). Funding for the behavioral work in Sabangau was provided by Chester Zoo and the North of England Zoological Society, Columbus Zoo and Aquariums, and Primate Conservation, Inc. The Robertson Foundation provided funding for the majority of the camera trap survey work presented here. For their additional financial support, we thank Panthera, International Animal Rescue (IAR) Indonesia, Borneo Nature Foundation, The Barito River Initiative for Nature Conservation and Communities (BRINCC), The Clouded Leopard Project/Point Defiance Zoo and Aquarium, Fresno Chafee Zoo and the Orangutan Foundation UK. We thank Erik Meijaard and Ikki Matsuda for their helpful suggestions and comments on an earlier draft of this manuscript.
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Cheyne, S.M., Supiansyah, Adul et al. Down from the treetops: red langur (Presbytis rubicunda) terrestrial behavior. Primates 59, 437–448 (2018). https://doi.org/10.1007/s10329-018-0676-5
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DOI: https://doi.org/10.1007/s10329-018-0676-5