Effects of Breeding in Captivity on Conflict among Wild Rats

The Biology and Behaviour of a Free-Living Population of Black Rats (Rattus rattus)

“…Amongst Eibl-Eibesfeldt's rats also, females made attacks on introduced aliens. Possibly the discrepancies may be related to how long and in what conditions the animals had been bred in captivity, for Barnett & Stoddart (1969) have found in R. norvegicus a decrease in pro· pensity to attack after a few generations of breeding in captivity, but they are more likely to be a function of the living conditions, for even my caged animals had considerablY more freedom than Barnett's. Yet another difference between my rats and Barnett's is that he found that littermates reared together did not mate, which was not true of my caged animals.…”

Effects of rearing on homosexual behavior in the male laboratory rat

“…In the present study, offensive postures and mounts were significantly correlated in Group 1. An interloper with its tendency to be submissive is a p par e n tly a good releaser for mounting when the males are at least somewhat domesticated (Barnett & Stoddart, 1969). Interlopers in the present study displayed only submissive postures.…”

Dominance-subordinance in cohabiting pairs of adult rats: Effects on Aggressive behavior

“…During the first 20 min of intruder presence, the experimenter recorded frequency and duration of fights (Barnett and Stoddart, 1969), frequency of resolved encounters (fights ending with one animal in the full aggressive posture and the other in the submissive posture), and the frequency and duration of offensive upright and full aggressive postures (Grant and Mackintbsh, 1963) of residents. Intruders and residents were left undisturbed for an additional 21 hr.…”

“…While very little aggression occurs in undisturbed colonies of rats, unfamiliar conspecifics are vigorously attacked (Barnett et al, 1968;Barnett and Stoddart, 1969;Galef, 1970). Apparently not all colony members -nor even all adult males -participate equally in attacking an intruder.…”