Olfactory mechanisms affording protection from attack to juvenile mice (Mus musculus L.).

The extent to which odours protect juvenile mice, Mus musculus L., from attacks was investigated in 6 experiments by measuring a) social responses within caged pairs of adult hermaphrodite hermaphodite after one partner was marked with either male or female juvenile's urine, and b) attacks suffered by adult males, juveniles of both sexes, and by adult hermaphrodites marked with these urines, after being introduced individually into territories of dominant hermaphrodites. The finding that urine of female but not that of male juveniles contains an active aggression-inhibitor and the questions this raises concerning the nature of the male juvenile's immunity are critically discussed.