Supplementary Material S1: Observed drinking behaviour in primates from water-filled tree holes.

Water is an indispensable source of all life forms on Earth, vital to many physiological and environmental processes. Like all animals, folivore primates depend on supplemental water to maintain hydration, constrained by a leaf-based diet containing high fibre content and stored secondary compounds; however, such reports are scarce from wild populations. Here, we report an opportunistic sighting of water ingestion by a troop of Capped langur, Trachypithecus pileatus, from a tropical forest fragment during the wet season from water accumulated in a tree hole, and end with a note advocating its importance in forest management plans. Understanding their significance can guide conservation efforts.

水是地球所有生命形式不可或缺的生存资源，对诸多生理与环境过程均至关重要。与所有动物一样，食叶灵长类需通过补充饮水维持机体水合平衡，但其以高纤维含量且储存次生代谢物的叶片为主食的饮食结构，限制了天然水分获取途径。然而，目前针对野生食叶灵长类的此类研究报告仍较为匮乏。本研究报道了一次偶然观测结果：在湿季，一群戴帽叶猴（Capped langur，Trachypithecus pileatus）利用热带森林片断内树洞内蓄积的积水饮水。文末我们倡议将该类饮水行为的重要性纳入森林管理规划范畴。明晰此类行为的生态学意义，可为相关保护工作提供科学指引。