Use of Water Content in the Diets by the François’ Langurs (<i>Trachypithecus </i><i>francoisi</i>) during Dry Season in Guangxi

水分对野生动物的存活至关重要。在水分相对缺乏的生境中，野生动物对水分的利用效率与物种的存活密切相关。2023年11月~12月，采用瞬时扫描取样法对广西崇左白头叶猴国家级自然保护区内一群黑叶猴(Trachypithecus francoisi)的觅食行为进行研究，采用重量法对猴群食物的含水量进行测定，旨在探讨旱季时期黑叶猴的食物选择与水分含量的关系。研究结果表明，黑叶猴的食物平均含水量为67.8% ± 7.1%。黑叶猴的非食物部位的平均含水量为55.1% ± 7.2%。比较发现，黑叶猴的食物种类与非食物种类的平均水分含量有明显的差异，表现为食物种类的含水量显著高于非食物种类(Z = −3.671, n = 29, p Water availability is crucial for wildlife survival in arid environments, where water use efficiency directly correlates with species viability. During November and December 2023, we investigated the foraging behavior of a François’ langur (Trachypithecus francoisi) group in the Guangxi Chongzuo White-headed Langur National Nature Reserve during dry season, using instantaneous scan sampling. The water content of dietary plants was quantified through gravimetric analysis to examine the relationship between food selection and water content. The results showed that dietary items exhibited mean water content of 67.8% ± 7.1% (mean ± SD) during dry season. Non-food plant parts contained substantially lower water contents (55.1% ± 7.2%). Our results also revealed significantly higher water content in consumed vs. non-dietary plants (Z = −3.671, n = 29, p < 0.001). Moreover, significant positive correlation between feeding frequency and water contents was observed (r = 0.746, n = 19, p < 0.001). These results suggest that François’ langurs preferentially select high-moisture plants as foods during dry season, potentially representing an evolutionary adaptation to limited surface water availability in karst forests.