Spatial cohesion in group-living animals is assumed as a risk-sensitive characteristic. Few studies have explicitly investigated this assumption or asked whether risk-related changes in spatial cohesion operate over short-term or long-term scales. We explored whether two groups of wild samango monkeys, Cercopithecus albogularis schwarzi, would adjust cohesion in reaction to naturally occurring risk from eagles and intergroup encounters using the number of conspecific neighbours as our response. Data on these directly observed encounters were used to assess reactive responses to immediate events. GPS-recorded locations of these encounters allowed us to create relative risk landscapes to investigate whether these groups might pre-emptively increase cohesion in high risk locations, in the absence of a direct threat. Multimodel inference was used to compare support for candidate models representing biological hypotheses. We found support for changes in cohesion in reaction to immediate intergroup conflict in both study groups. In contrast, only eagle risk apparently elicited a pre-emptive response. These results suggest that spatial cohesion is risk sensitive, but that responses differ between types of risk and between groups.

中文翻译：

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社会灵长类动物的反应性和先发制人的空间凝聚力

群体生活动物的空间凝聚力被假定为风险敏感特征。很少有研究明确调查这一假设或询问与风险相关的空间凝聚力变化是否在短期或长期尺度上起作用。我们探索了两组野生 samango 猴子 Cercopithecus albogularis schwarzi 是否会使用同种邻居的数量作为我们的反应来调整凝聚力以应对来自鹰和群际相遇的自然发生的风险。这些直接观察到的遭遇的数据被用来评估对即时事件的反应性反应。这些遭遇的 GPS 记录位置使我们能够创建相对风险格局，以调查这些群体是否可能在没有直接威胁的情况下先发制人地提高高风险地区的凝聚力。多模型推理用于比较对代表生物学假设的候选模型的支持。我们发现在两个研究组中都支持改变凝聚力以应对直接的群体间冲突。相比之下，只有鹰风险显然引起了先发制人的反应。这些结果表明空间凝聚力是风险敏感的，但反应在风险类型和群体之间有所不同。