Flexible Foraging Movements Enable Hainan Gibbons (

Animals exhibit different foraging movement strategies in environments characterized by patchily distributed resources and pronounced seasonal variation. Hainan gibbon (Nomascus hainanus) is a Critically Endangered primate that relies heavily on mature fruits, inhabiting tropical rainforests where food resources are characterized by pronounced spatiotemporal heterogeneity, yet its foraging search strategies remain poorly understood. This study conducted two years of field monitoring on the groups C and E of Hainan gibbons (Nomascus hainanus), with Group C inhabiting old growth forest and Group E inhabiting secondary forest. Gibbon behaviors were recorded at 5-minute intervals using instantaneous scan sampling, and the spatial locations of behaviors were documented at 15-minute intervals. The results showed that, at the spatial scale, Group C exhibited higher movement directionality and a greater proportion of extensive search characterized by straighter, long distance displacements. In contrast, Group E spent a lower proportion of time in extensive search and exhibited longer mean step lengths but weaker directionality. At the temporal scale, gibbons primarily engaged in short distance, localized intensive search during the mixed diet period, whereas during the fruit-eating phase , the proportion of time spent in the extensive search phase was increased. Overall, Hainan gibbons flexibly switch between extensive and intensive search modes to achieve directional inter-patch movements while maximizing within patch exploitation, thereby effectively coping with temporal and spatial variation in fruit resources. These findings provide important insights for habitat management and conservation planning for Hainan gibbons in heterogeneous environments.

动物在资源呈斑块状分布且季节波动显著的环境中，会演化出差异化的觅食移动策略。海南长臂猿（Nomascus hainanus）是一种极危（Critically Endangered）灵长类动物，高度依赖成熟果实，栖息于食物资源呈现显著时空异质性的热带雨林中，但其觅食搜索策略迄今仍鲜为人知。
本研究对海南长臂猿（Nomascus hainanus）的C群与E群开展了为期两年的野外监测：C群栖息于原始成熟林，E群则栖息于次生林。研究采用瞬时扫描取样法（instantaneous scan sampling），以5分钟为间隔记录长臂猿的行为，并以15分钟为间隔记录其行为发生的空间位置。
结果显示：在空间尺度上，C群的移动方向性更强，且以直线长距离移动为特征的广域搜索占比更高；与之相反，E群用于广域搜索的时间占比更低，尽管其平均步长更长，但移动方向性更弱。在时间尺度上，杂食采食期长臂猿主要开展短距离局地集中搜索；而在纯果食期，其用于广域搜索的时间占比有所提升。
总体而言，海南长臂猿可在广域搜索与集中搜索模式间灵活切换，既能实现斑块间的定向移动，又能最大化斑块内的资源利用效率，从而有效应对果实资源的时空异质性变化。本研究结果为异质环境下海南长臂猿的栖息地管理与保护规划提供了重要参考依据。