Department of Evolutionary Zoology and Human Biology, University of Debrecen, Debrecen, Hungary.
Faculty of Life Sciences, Institute of Biology, Human Biology & Primate Cognition, Leipzig University, Leipzig, Germany.
Sci Rep. 2024 Nov 4;14(1):26672. doi: 10.1038/s41598-024-77805-9.
Behavioral contagion is thought to play a significant role in social synchronization and coordination across animal taxa. While there is extensive evidence of behavioral contagion in Haplorrhines (i.e. monkeys and apes), limited research exists in Strepsirrhines (i.e. lemurs). Here, we aimed to investigate the presence of contagious yawning and scratching in two captive groups of black-and-white ruffed lemurs (Varecia variegata) (N = 4) and red ruffed lemurs (Varecia rubra) (N = 4), and further test whether behavioral contagion is modulated by the model's social integration in the group. We conducted all occurrence sampling to examine whether individuals observing a yawning or scratching event (i.e. trigger event) were more likely to yawn or scratch in the following 2 min, as compared to individuals who did not observe it. We ran generalized linear mixed models and found that the likelihood of yawning and scratching was higher for subjects observing the trigger event than for subjects who did not observe the event, although the model's social integration had no modulating effect on the probability of showing behavioral contagion. Our findings represent the first evidence of behavioral contagion in this genus and contribute to shed light on the distribution and the possible adaptive function of this phenomenon in primates.
行为传染被认为在动物分类中对社会同步和协调起着重要作用。虽然在原猴类（即猴子和猿类）中广泛存在行为传染的证据，但在懒猴类（即狐猴）中研究有限。在这里，我们旨在调查两只圈养的黑白卷尾猴（Varecia variegata）（N=4）和红领狐猴（Varecia rubra）（N=4）中是否存在传染性打哈欠和抓挠行为，并进一步测试行为传染是否受到模型在群体中社会融合的调节。我们进行了所有出现的抽样，以检查观察到打哈欠或抓挠事件（即触发事件）的个体在下 2 分钟内打哈欠或抓挠的可能性是否高于未观察到该事件的个体。我们运行了广义线性混合模型，发现观察到触发事件的受试者打哈欠和抓挠的可能性高于未观察到事件的受试者，但模型的社会融合对表现出行为传染的概率没有调节作用。我们的发现代表了该属中行为传染的第一个证据，并有助于阐明这种现象在灵长类动物中的分布和可能的适应功能。
