Effects of housing on male and female rats: Crowding stresses males but calms females (1995)

Brown, K. J., Grunberg, N. E.

Abstract

Male rats had higher plasma corticosterone levels when housed in groups than when housed individually. Corticosterone levels increased with decreasing space allowance for the group. Females on the other hand had highest corticosterone when housed alone, and increasing social density did not increase corticosterone levels.