Large carnivore dangerousness affects the reactive spatial response of prey

Predators differ through different attributes: their body size, sociality, speed, preferred prey size, hunting mode, etc. Altogether these characteristics contribute to shape an overall dangerousness, which is likely to underlie the variations in the nature and strength of a prey anti-predator responses. This link, although somehow intuitive, has been rarely quantified in natural ecosystems.
The goal of this study is to compare the antipredator response of a prey to two predators with contrasting dangerousness in large terrestrial mammals, focusing on the less studied reactive spatial response. We assessed if plains zebras’ (Equus quagga) reactive spatial response differed after an encounter with African lions (Panthera leo) or spotted hyaenas (Crocuta crocuta). We expected lions to be perceived as more dangerous and hence to induce a stronger reactive spatial response than hyaenas.
Using data from GPS collars deployed simultaneously on the three species, we studied the reactive spatial responses of zebras after coming into close proximity to either predator.

We found that zebras responded differently, and more strongly to lions than to hyaenas. Indeed, zebras were twice more likely to flee after an encounter with a lion than a hyaena and, immediately after an encounter with a lion, zebras moved on average faster and further than after an encounter with a hyaena.
The results of this study are consistent with a correlation between the predator dangerousness and the strength of the prey anti-predator response. Future studies covering other pairs of large carnivores are needed to rigorously assess the role of the different predator attributes (body size, speed, preferred prey, and hunting mode).

捕食者的属性存在诸多差异，涵盖体型、社会性、移动速度、偏好猎物体型、捕猎模式等。上述所有特征共同塑造了捕食者的整体危险性，而该危险性很可能是猎物反捕食响应（antipredator response）的性质与强度产生差异的核心基础。尽管这一关联在直觉上易于理解，但在自然生态系统中却鲜有量化研究。
本研究旨在对比大型陆生哺乳动物中，猎物对两种危险性存在显著差异的捕食者的反捕食响应，重点关注此前研究关注度较低的反应性空间响应（reactive spatial response）。我们针对平原斑马（Equus quagga）在遭遇非洲狮（Panthera leo）或斑鬣狗（Crocuta crocuta）后的反应性空间响应是否存在差异展开了评估，并提出研究假设：相较于斑鬣狗，非洲狮会被猎物判定为更具危险性，因此能够诱发更强的反应性空间响应。
本研究借助同步部署于三个物种种群的GPS项圈所采集的定位数据，分析了斑马在近距离接触任意一种捕食者后的反应性空间响应。
研究结果显示，斑马对两种捕食者的响应存在显著差异，且对非洲狮的响应强度更高。具体而言，斑马在遭遇非洲狮后发生逃跑行为的概率是遭遇斑鬣狗后的两倍；且在遭遇非洲狮后，斑马的平均移动速度与移动距离均显著高于遭遇斑鬣狗后的水平。
本研究结果与"捕食者危险性与猎物反捕食响应强度之间存在关联"这一推论相符。未来需针对其他大型食肉动物组合开展相关研究，以严谨评估捕食者各项属性（体型、移动速度、偏好猎物、捕猎模式）在该关联中发挥的具体作用。