An analysis of responses to snakes by Japanese field mice Apodemus supeciosus.

Abstract

Many studies have been reported on the ecology of the Japanese field mouse Apodemus speciosus. However, there are no studies examining the responses by Apodemus speciosus to snakes, which is thought to have important influences on the lives of this species in the field. In the present study, the response of Apodemus speciosus to snakes was examined under experimental conditions. In Experiment I, how they respond to snakes on the ground and how they discriminate between snakes and other reptiles in the dark were examined. The mice exhibited elongate investigative posture, tail vibration, and displacement grooming much more frequently to snakes than to tortoises. The mice approached snakes in a much shorter time than they approached tortoises. In Experiment II, the response of mice to snakes which spontaneously intruded and hid in the mouse nest burrow was examined. All mice hesitated to enter the nest. Some mice exhibited elongate investigative posture and tail vibration near the entrance of the nest burrow and plugged uptheentrancewithsoil. TheresponseofApodemus speciosus to snakes was compared with other rodent species. The relationship between the response pattern and the biological characteristics of each rodent species was discussed.