Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, Minnesota, United States of America.
PLoS One. 2021 Aug 18;16(8):e0256147. doi: 10.1371/journal.pone.0256147. eCollection 2021.
Large mammalian herbivores use a diverse array of strategies to survive predator encounters including flight, grouping, vigilance, warning signals, and fitness indicators. While anti-predator strategies appear to be driven by specific predator traits, no prior studies have rigorously evaluated whether predator hunting characteristics predict reactive anti-predator responses. We experimentally investigated behavioral decisions made by free-ranging impala, wildebeest, and zebra during encounters with model predators with different functional traits. We hypothesized that the choice of response would be driven by a predator's hunting style (i.e., ambush vs. coursing) while the intensity at which the behavior was performed would correlate with predator traits that contribute to the prey's relative risk (i.e., each predator's prey preference, prey-specific capture success, and local predator density). We found that the choice and intensity of anti-predator behaviors were both shaped by hunting style and relative risk factors. All prey species directed longer periods of vigilance towards predators with higher capture success. The decision to flee was the only behavior choice driven by predator characteristics (capture success and hunting style) while intensity of vigilance, frequency of alarm-calling, and flight latency were modulated based on predator hunting strategy and relative risk level. Impala regulated only the intensity of their behaviors, while zebra and wildebeest changed both type and intensity of response based on predator traits. Zebra and impala reacted to multiple components of predation threat, while wildebeest responded solely to capture success. Overall, our findings suggest that certain behaviors potentially facilitate survival under specific contexts and that prey responses may reflect the perceived level of predation risk, suggesting that adaptive functions to reactive anti-predator behaviors may reflect potential trade-offs to their use. The strong influence of prey species identity and social and environmental context suggest that these factors may interact with predator traits to determine the optimal response to immediate predation threat.
大型食草哺乳动物利用多种策略来应对捕食者的袭击，包括逃跑、群体、警戒、警告信号和适应能力指标。虽然抗捕食策略似乎是由特定的捕食者特征驱动的，但以前没有研究严格评估过捕食者的狩猎特征是否可以预测反应性的抗捕食反应。我们通过实验研究了自由放养的大角斑羚、角马和斑马在与具有不同功能特征的模型捕食者相遇时所做出的行为决策。我们假设，反应的选择将由捕食者的狩猎风格（即伏击与追逐）驱动，而行为的执行强度将与导致猎物相对风险的捕食者特征相关（即每个捕食者的猎物偏好、猎物特异性捕获成功率和当地捕食者密度）。我们发现，抗捕食行为的选择和强度都受到狩猎风格和相对风险因素的影响。所有猎物物种对捕获成功率较高的捕食者保持更长时间的警戒。逃跑的决定是唯一由捕食者特征（捕获成功率和狩猎风格）驱动的行为选择，而警戒时间、报警叫声频率和逃跑潜伏期则根据捕食者的狩猎策略和相对风险水平进行调节。大角斑羚只调节其行为的强度，而斑马和角马则根据捕食者特征改变行为的类型和强度。斑马和大角斑羚对捕食威胁的多个组成部分做出反应，而角马则仅对捕获成功率做出反应。总的来说，我们的研究结果表明，某些行为在特定情况下可能有助于生存，而猎物的反应可能反映出对捕食风险的感知程度，这表明对反应性抗捕食行为的适应性功能可能反映了其使用的潜在权衡。猎物物种身份以及社会和环境背景的强烈影响表明，这些因素可能与捕食者特征相互作用，以确定对即时捕食威胁的最佳反应。
