|| 要旨トップ | 目次 |||日本生態学会第64回全国大会 (2017年3月、東京) 講演要旨
一般講演（口頭発表） K01-06 （Oral presentation）
The immobile state of a prey animal that is exhibited when confronted by a predator is a representative defensive behavior in many animals. Performing this immobility after being detected by a predator has been considered to be non-adaptive because it simply allows the predator to come closer. Nonetheless, even after being detected, some animals often remain motionless for a while before escaping. We hypothesized that this non-immediate escape response increases the survivorship of the prey by distracting the predator’s attention to another nearby prey. Staged encounter experiments using frogs and snakes as prey and predator, respectively, yielded the results that support this hypothesis. The snakes slowly and inconspicuously approached a motionless frog, which would increase the opportunity that other frogs coincidentally come into the perceptual field of the snake without noticing the snake. When another frog moved nearby the motionless frog, the attention of the snakes was distracted from the motionless frog to the moving frog, and the motionless frog survived at the expense of the other frog. Therefore, remaining motionless was suggested to be an effective choice to avoid predation even after being detected by a predator under a certain circumstance.