PDF(Pubmed)
Abstract：
Masquerade is a form of camouflage in which animals use their body size, shape, and coloration to resemble inanimate objects in their environment to deceive predators. However, there is a lack of experimental evidence to show that animals actively choose objects that match these body parameters. To explore how the Hainan four-eyed turtle, Sacalia insulensis, masquerades using suitable stones, we used indoor video surveillance technology to study the preferences of juvenile S. insulensis for stones of different sizes, shapes, and colors. The results indicated that under normal conditions, during the day, juvenile S. insulensis preferred larger oval or round stones, while at night, they preferred oval stones that were closer to their own size, with no significant preference for stone color during either time. When disturbed (by a researcher swinging their arm back and forth above the experimental setup every hour to mimic a predator), the turtles showed a preference for brown stones that were closer to their size and oval in shape. These findings suggest that juvenile S. insulensis prefer stones that resemble their carapace size and shape to masquerade when undisturbed, and that this preference is reinforced when they masquerade to reduce the risk of predation. The preference for stones that resemble their carapace color is significant only when there is a disturbance. To the best of our knowledge, this is the first study to provide evidence that vertebrates can selectively choose objects that resemble their own morphology for masquerading to reduce predation risk.
摘要：
化装舞会是一种伪装形式，动物使用它们的体型，形状,和着色类似于环境中的无生命物体来欺骗捕食者。然而,缺乏实验证据表明动物会主动选择与这些身体参数相匹配的物体。探索海南四眼龟，苏丹,化装舞会使用合适的石头，我们使用室内视频监控技术研究了苏丹幼鱼对不同大小石头的偏好，形状,和颜色。结果表明,在正常情况下,白天,幼年S.insulensis首选较大的椭圆形或圆形的石头，而在晚上,他们更喜欢更接近自己大小的椭圆形石头，在任何时候都没有明显的宝石颜色偏好。当受到干扰时（研究人员每小时在实验装置上方来回摆动手臂以模仿捕食者），海龟偏爱棕色的石头，更接近它们的大小和椭圆形。这些发现表明，幼年S.insulensis更喜欢与甲壳大小和形状相似的石头，当他们伪装以降低捕食风险时，这种偏好得到了加强。只有当存在干扰时，对类似其甲壳颜色的石头的偏好才是重要的。据我们所知,这是第一项研究提供的证据表明，脊椎动物可以选择性地选择与自身形态相似的物体进行伪装，以降低捕食风险。
