An increasing body of evidence indicates that moonlight influences the nocturnal activity patterns of tropical mammals, both predators and prey. One explanation is that brighter moonlight is associated with increased risk of predation (Predation Risk hypothesis), but it has also been proposed that nocturnal activity may be influenced by the sensory ecology of a species, with species that rely on visual detection of food and danger predicted to increase their activity during bright moonlight, while species relying on non-visual senses should decrease activity (Visual Acuity hypothesis). Lack of an objective measure of “visual acuity” has made this second hypothesis difficult to test, therefore we employed a novel approach to better understand the role of lunar illumination in driving activity patterns by using the tapetum lucidum as a proxy for “night vision” acuity. To test the alternative predictions, we analyzed a large dataset from our long-term camera trap study in Costa Rica using activity overlap, relative abundance, and circular statistical techniques. Mixed models explored the influence of illumination factors (moonrise/set, cloud cover, season) and night vision acuity (tapetum type) on nocturnal and lunar phase-related activity patterns. Our results support the underlying assumptions of the predation risk and visual acuity models, but indicate that neither can fully predict lunar-related activity patterns. With diurnal human “super predators” forcing a global increase in activity during the night by mammals, our findings can contribute to a better understanding of nocturnal activity patterns and the development of conservation approaches to mitigate forced temporal niche shifts.

中文翻译：

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月光会增加哥斯达黎加难以捉摸的哺乳动物的捕食风险吗？

越来越多的证据表明，月光会影响热带哺乳动物（包括捕食者和猎物）的夜间活动模式。一种解释是，更明亮的月光与捕食风险增加有关（捕食风险假设），但也有人提出夜间活动可能受到物种感官生态的影响，物种依赖于对食物和危险的视觉检测预计在明亮的月光下会增加它们的活动，而依赖非视觉感官的物种应该会减少活动（视敏度假设）。缺乏“视觉敏锐度”的客观衡量标准使得第二个假设难以检验，因此，我们采用了一种新颖的方法，通过使用绒毡层作为“夜视”敏锐度的代理，更好地了解月球照明在驾驶活动模式中的作用。为了测试替代预测，我们使用活动重叠、相对丰度和循环统计技术分析了来自我们在哥斯达黎加的长期相机陷阱研究的大型数据集。混合模型探讨了光照因素（月出/落月、云量、季节）和夜视敏锐度（tapetum 型）对夜间和月相相关活动模式的影响。我们的结果支持捕食风险和视力模型的基本假设，但表明两者都不能完全预测与月球相关的活动模式。随着昼夜活动的人类“超级捕食者”迫使哺乳动物在夜间活动的全球增加，