Responses of male and female laboratory mice to the odor of conspecifics of the same sex: Effects of previous isolation and grouping

Abstract

Preference of isolated or grouped mice for their home cage odor vs. the odor of a strange individual or group was tested by using both connected cages and large arenas. When having been isolated prior to the test, both males and females preferred the odor of other strange individuals of the same sex to their own odor. This tendency was not changed by gonadectomy. In males, it was also confirmed that an isolated male preferred the odor of a dominant male, by which it had been defeated before the test, to its own odor. Further study revealed that they prefer the odor of strange males to clean shavings, while they did not show any particular preference between their own odor and clean shavings. On the other hand, mice which had been housed in groups of 2 or 5 individuals did not show any particular preference between the odor of the familiar individuals and that of strange ones. These results suggest that isolated mice are attracted by the odor of other conspecifics (of the same sex, so far as the present study is concerned), probably by discriminating the odor of other individuals from that of their own. This tendency cannot be attributed to the curiosity for the strange odor when the response of grouped mice is considered. It is probable that the attractiveness of the odor of conspecifics is determined by the social situation of the animal receiving it. Mouse odor seems to enhance group formation by isolated individuals.