In social animals, areas where the home ranges of neighboring groups overlap are often underused. The Risk Hypothesis posits that the costs of intergroup conflict create a “landscape of fear,” discouraging the use of such shared areas. To test this hypothesis, we observed the behavior of white-faced capuchins (Cebus capucinus) in central vs. peripheral areas of their home ranges. If capuchins perceive areas of home range overlap as “risky,” we predicted they would change activity budgets, vocalization rates, and foraging behavior in these areas. A spatially explicit behavioral comparison based on nearly 100 h of focal follows revealed that capuchins socialize less in the periphery (vs. the center) of their home range. Time spent resting, foraging, and engaging in vigilance, as well as vocalization rates, varied in consistent ways across all four study groups, but these differences did not reach statistical significance. Fruit trees near range borders (vs. the center) contained more ripe fruit, and groups spent more time in these trees, with more individuals entering to feed and consuming more fruits. However, capuchins did not alter their foraging behavior in potentially risky peripheral areas in a manner consistent with predictions of optimal foraging theory: intake rates at patch departure were not significantly lower and groups depleted trees to a greater extent along the periphery vs. in the center of their range. These results suggest that while peripheral areas are perceived as risky and this “landscape of fear” contributes to behavioral changes, they also provide resources whose value may outweigh the cost of intergroup encounters.

中文翻译：

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猴子会因为危险而避免家庭范围重叠的区域吗？白面卷尾猴 (Cebus capucinus) 风险假设的检验

在群居动物中，相邻群体的家园范围重叠的区域往往未被充分利用。风险假设假设群体间冲突的成本创造了一种“恐惧景观”，阻碍了对这些共享区域的使用。为了验证这一假设，我们观察了白脸卷尾猴 (Cebus capucinus) 在其栖息地的中央与外围区域的行为。如果卷尾猴认为家庭范围重叠的区域“有风险”，我们预测它们会改变这些区域的活动预算、发声率和觅食行为。基于近 100 小时焦点的空间明确行为比较显示，卷尾猴在其家庭范围的外围（相对于中心）社交较少。休息、觅食和保持警惕的时间以及发声率，在所有四个研究组中以一致的方式变化，但这些差异没有达到统计显着性。靠近山脉边界（相对于中心）的果树含有更多成熟的果实，并且群体在这些树上待的时间更长，有更多的个体进入并食用更多的果实。然而，卷尾猴并没有以与最佳觅食理论的预测一致的方式改变它们在潜在危险外围区域的觅食行为：斑块离开时的摄入率没有显着降低，并且与中心相比，沿着外围的群体在更大程度上消耗了树木他们的范围。这些结果表明，虽然外围区域被认为是有风险的，而且这种“恐惧景观”有助于行为改变，但它们也提供了价值可能超过群体间相遇成本的资源。