Changes in Locomotor Activity Following Predator Odor Exposure are Dependent on Sex and Reproductive Status in the Meadow Vole

Abstract

Changes in locomotor activity levels following exposure to the odor of a potential predator, the red fox, were investigated in male and female meadow voles. Levels of various components of activity in male voles were decreased (for 30 min) following exposure to fox odor but not following exposure to other pungent, aversive control odors. Housing males with females prior to testing resulted in a decreased length of activity reduction (20 min) following fox odor exposure. Female voles that had been housed alone or in same-sex groups did not display a reduction in activity levels following exposure to fox odor. However, housing females with males, which has been shown to increase gonadal sex steroids in the female, resulted in a brief (5 min) period of activity reduction following exposure to fox odor. These results show that sex differences exist in the activity response of meadow voles to predation threat and suggest that gonadal hormones may be involved in the mediation of this response.