Aggression, Social Pressure and Asymptote in Laboratory Mouse Populations

Abstract

Freely growing populations of BALB/cJ, C57BR/cdJ and C57BL/6J mice were maintained until after asymptote in the presence of ad libitum food and water. If aggression were an index of social pressure then aggression at asymptote should be stable. After asymptote was reached aggression increased in two of the three strains. Therefore aggression as measured here does not index social pressure. BALB/cJ populations had more aggression and fewer mice at asymptote than did populations of the other two strains. The relative aggressiveness of these three strains depends on the environment in which they are observed.