Sex differences in aggressive behaviour in various strains of mice

Abstract

Two nonalbino inbred (C57 BL/6 and C3H/He) and one albino strain (Swiss) of mice were compared for female aggression toward intruders: 1 in period of lactation, 2 in nonlactating state and (3) in nonlactating state but previously rubbed with urine of lactating females; and for male aggression toward familiar or unfamiliar opponents. The results showed that resident females of the C57 and Swiss strain vigorously attack lactating intruders introduced into their cages. This effect was mediated by urinary cues emitted by the latter mice. It was also shown that Swiss residents displayed aggression towards nonlactating females, irrespective of their strain. Groups of C57 residents reacted most aggressively towards Swiss females, less aggressively towards C3H intruders, but did not show any aggression towards their own nonlactating conspecifics. In contrast, none of the C3H resident female groups displayed aggression towards intruding females of any category or strain. The results also showed that the males of the three strains displayed little (Swiss and C3H) or no aggression (C57) towards familiar opponents, whereas they directed increased aggressive responses towards unfamiliar ones. Comparisons among the three strains of mice revealed that Swiss males were the most aggressive in either situation. On the other hand, the finding that C3H males showed aggressive responses suggested that male and female aggression are, in this strain, under separate genetic or hormonal control.

Effect of reciprocal cross‐fostering on aggression of female mice toward lactating strangers

“…Another strain of mice (C57 BL/6) directed attacks against lactating but not against nonlactating females. In a subsequent study, Haug and Mandel (1978b) showed that odoriferous factors were implicated in that aggression-stimulating effect and that the olfactory factor (a urinary one) is produced by the lactating females of the 3 strains.…”

Inherited and rearing components of aggressive dominance and autonomic reactivity in the rat

“…It is possible that there is natural selection for some genes in males to respond more quickly and strongly to environmental pressures than females. In fact, Haug and Mandel (1978) found in mice that the aggression of the two sexes was under separate genetic or hormonal control Singh et al (1984) reported that even in monkeys, the behavioural responses to harsh and hostile environments are more marked in males, even to the extent of resulting in a higher male mortality as compared to females. …”