Studies on the Behavior of Sorex Vagrans

Abstract

The individual and social behavior patterns of adult and immature Sorex vagrans were studied in the laboratory. Isolated shrews were observed in simulated natural habitats in order to describe the behavior of solitary individuals. The social behavior patterns were studied by (1) establishing groups of adults and immature shrews in the same cage, and (2) staging a series of three-minute encounters be- tween two individuals in a neutral testing arena. The shrews could be kept in groups with little fighting but the adults denned separately. Immature shrews denned together until they were about 7 weeks old. In the staged encounters agonistic behavior patterns accounted for only 4-5% of all the social interactions. Moving away was the most fre- quent response comprising almost 40% of the social behavior recorded. Encounters between animals from the same group were free from agonistic behavior. On the other hand, shrews encountering as strangers showed occasional bouts of chasing and fighting behavior. The imma- ture shrews displayed little agonistic behavior when encountering a strange immature, but at three months of age the same animals showed agonistic tendencies.