Predatory behaviour in females of two strains of mice selectively bred for isolation-induced intermale aggression

The study sought to determine whether females of two strains of mice selectively bred for high (Turku Aggressive, TA) and low (Turku Non-Aggressive, TNA) levels of isolation-induced intermale aggression display differences in predatory behaviour. Additional subjects used in the study were females of the parental strain (Normal, N). Another aim of the present research was to investigate whether predatory aggression is associated with the postpartum period in the TA and TNA females. Testing consisted of dropping a live cricket into the home cage of the experimental females. The results showed that the predatory behaviour of individually housed TA and TNA females did not differ significantly. The only difference found between the two groups of females was in digging behaviour, the TA females showing more of this activity element on the first day of testing. Experience was found to affect the behaviour of the mice, attacking and consuming increased over trials whereas sniffing and the latency to attack decreased. In another experiment, TA and TNA females were tested for predatory aggression on the third day postpartum. The TA and TNA females were found to differ in all other observed behaviour variables but sniffing. The TA females spent more time chasing, tail-rattling, attacking, and consuming, as well as showing shorter latencies to the first attack. The TNA females spent more time digging, grooming, and nursing. The results suggest that the mechanisms determining the dispositions for predatory and maternal aggression in females and isolation induced intermale aggression and predatory aggression in males are not entirely different.