Population density, mouse genotype, and endocrine function in behavior.

Abstract

In comparison with behavior in isolation, 6 strains of inbred mice, C57BL, BALB/c, DBA/2, A, C3H/2,and R111, respond to increase in population size of 10 and 20 with heightened behavioral reactivity within the population confines and during tests on 2 different measures of exploration. Adrenal and testis reactivity shows more individuality among strains; however, in most cases within-group variance of adrenal weight is lower at higher densities. Genotype sets the limits of response for both behavioral and endocrine measures, although these appear to be regulated independently.