Suncus murinus as a novel model animal that is suitable for elucidating the mechanism of daily torpor.

Torpor, a state of lowered body temperature due to active reduction of the metabolic rate, has potential medical benefits. The aim of this study was to establish a novel laboratory animal that enter torpor without imposing complex conditions. When house musk shrews (Suncus murinus) were kept at an ambient temperature of 24°C, most of the animals did not enter daily torpor. However, when the ambient temperature was lowered to below 20°C, all of the shrews showed torpor in the absence of fasting and short-day photoperiod. The shrews that were exposed to a stepwise decrease in ambient temperature from 24°C to 8°C entered torpor even after returning them to a room kept at 24°C. In conclusion, this study indicates that Suncus murinus may be a suitable model animal for elucidating the mechanism of daily torpor. Elucidation of the mechanisms of torpor by using this model may be useful for inducing a state of artificial hibernation in various species including humans.