Cheyne Susan M, Neale Claire J, Thompson Carolyn, Wilcox Cara H, Smith Yvette C Ehlers, Smith David A Ehlers
Borneo Nature Foundation, Jl. Bukit Raya Induk No. 82, Palangka Raya, Indonesia.
Faculty of Humanities, Social Sciences and Law, Oxford Brookes University, Oxford, UK.
Primates. 2018 Sep;59(5):437-448. doi: 10.1007/s10329-018-0676-5. Epub 2018 Jul 19.
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.
通过在印度尼西亚婆罗洲的八个地点进行直接观察和使用相机陷阱，我们发现红毛猩猩（Presbytis rubicunda）比之前认为的更常出现在地面上，它们经常下地。在调查的八个地点中的六个都发现了这种不寻常的行为。我们发现，红毛猩猩在受干扰的森林中更频繁地来到地面，特别是那些受到伐木、火灾和狩猎影响的森林，不过还需要更多数据来证实这是一种直接关联。我们还发现随着栖息地海拔升高，红毛猩猩在地面活动的频率有下降趋势。当红毛猩猩在地面时，它们主要进行觅食（直接观察中占50%，相机陷阱记录中占61%）和移动（直接观察中占29%，相机陷阱记录中占13%）。红毛猩猩全天都会出现在地面上，与顶级捕食者巽他云豹（Neofelis diardi）的活动时间相似。我们认为，红毛猩猩在地面活动可能是对受干扰森林的一种适应，以便利用额外的食物来源并便于移动。
