Primate Research Institute, Kyoto University, Inuyama, Japan; Center for Education and Research in Field Science, Faculty of Agriculture, Shizuoka University, Hamamatsu, Japan.
School of Human Sciences, Osaka University, Suita, Japan.
Behav Processes. 2021 Jan;182:104279. doi: 10.1016/j.beproc.2020.104279. Epub 2020 Nov 12.
Group-living animals gain fitness benefits from intergroup aggression, but also incur costs. Advertisement behaviors, such as long-distance calls and scent marking, help animals avoid disadvantageous, or less rewarding, fights. However, it remains unclear how species that lack advertisement behaviors respond to auditory information from other groups. We hypothesized that such species use auditory information prior to visual contact with the opponent group to determine its relative resource holding potential. Here, we aimed to identify the behavioral responses of Japanese macaques to simulated intergroup encounters. We conducted a vocal playback experiment and behavioral observations of 11 adult males and females from two groups intermittently from October 2015 to June 2017. In response to vocalizations of other groups, the macaques stopped feeding, decreased contact calling, and increased visual scanning, which could enable them to make timely and accurate decisions as to whether to fight or flee. The spatial cohesion of the group did not change. These results partly support our hypothesis and suggest that the onset of increased vigilance to opponents is prior to visual contact with them. The present study highlights the importance of investigating early phases of intergroup encounters in species lacking advertisement behaviors to obtain new insights on intergroup conflicts in animals.
群居动物通过群体间的攻击获得适应度优势，但也会付出代价。广告行为，如远距离呼叫和气味标记，有助于动物避免不利的或回报较低的战斗。然而，目前尚不清楚缺乏广告行为的物种如何对来自其他群体的听觉信息做出反应。我们假设这些物种在与对手群体进行视觉接触之前，会利用听觉信息来确定其相对资源持有潜力。在这里，我们旨在确定日本猕猴对模拟群体间相遇的行为反应。我们从 2015 年 10 月到 2017 年 6 月，间歇性地对来自两个群体的 11 只成年雄性和雌性猕猴进行了发声播放实验和行为观察。对其他群体的叫声的反应，猕猴停止进食，减少接触呼叫，并增加视觉扫描，这使它们能够及时准确地做出是否战斗或逃跑的决定。群体的空间凝聚力没有改变。这些结果部分支持了我们的假设，并表明对对手的警惕性的增强先于与它们的视觉接触。本研究强调了在缺乏广告行为的物种中研究群体间相遇的早期阶段的重要性，以获得对动物群体间冲突的新见解。
