Exploration by the deer mouse, Peromyscus leucopus

The exploration of new objects and new environments by Peromyscus leucopus was observed in laboratory pens and inferred from the number of smoked paper track records obtained from track shelters (milk cartons or tin cans) in the field. The exploration and settling of uninhabited islands by introduced mice were followed by plotting the locations of track records. This species exhibits a weak neophobia (avoidance of new stimuli) which is soon replaced by a strong neophilia (attraction to new stimuli). This resulted in large numbers of track records on the first night that novel track shelters were in place, with declining numbers on subsequent nights. Moving familiar shelters to new locations slightly increased the number of records. Baiting the shelters greatly increased the number of records. The mice apparently treat the shelters as a class of objects- on the first night that a mouse encountered bait in a shelter it left tracks in a large number of shelters. Mice introduced to uninhabited islands quickly dispersed over them and settled on fairly stable home ranges. Different colonies introduced to the same island showed very different patterns of exploration. Eventually each mouse left tracks at most or all of the stations in its home range. Failure to leave a record was caused sometimes by failure to encounter the track shelter (shelter not in the area used by the mouse), sometimes by failure to enter a shelter when it was encountered (failure to explore). The mice repeatedly explored their home ranges, as indicated by repeated records from a station, but some stations were tracked much more than others. Young mice slowly extended their movements over the island after first beginning to travel away from the maternal nest