Gregory Patrick T, Isaac Leigh Anne, Griffiths Richard A
Department of Biology, University of Victoria, Victoria, British Columbia, Canada.
J Comp Psychol. 2007 May;121(2):123-9. doi: 10.1037/0735-7036.121.2.123.
Death feigning, a variant of tonic immobility, is usually interpreted as a last-resort antipredator measure. The authors describe death feigning in grass snakes (Natrix natrix) and test some of its potential correlates. Death feigning was seen in 66% of wild-caught snakes but was not seen in hatchlings from laboratory-incubated eggs. Minimal indication of death feigning was mouth gaping, often with the tongue hanging free, but more dramatic cases involved voluntary supination and/or lack of muscle tone. Aside from hatchlings, which did not feign death, there was little variation in frequency or intensity of death feigning with body size. There was no effect of body temperature on death feigning nor were snakes that were moving when caught less likely to feign death than those that were not moving. Interpretation of the adaptive value of death feigning in grass snakes or in other animals is hampered by lack of evidence of this behavior in the field in response to natural predators.
装死是强直性静止的一种变体，通常被解释为一种最后的反捕食者措施。作者描述了草蛇（游蛇）的装死行为，并测试了其一些潜在的相关因素。在66%的野生捕获蛇中观察到装死行为，但在实验室孵化卵的幼蛇中未观察到。装死的最小迹象是嘴巴张开，舌头常常自由下垂，但更明显的情况包括自愿翻身和/或缺乏肌张力。除了不装死的幼蛇外，装死的频率或强度随体型变化不大。体温对装死没有影响，被捕时正在移动的蛇比不移动的蛇装死的可能性也没有更低。由于缺乏在野外针对自然捕食者时这种行为的证据，对草蛇或其他动物装死的适应性价值的解读受到了阻碍。
