Observations on fighting behaviour of male mice (Mus musculus L.).

Fighting behaviour of male mice was compared in 8 wild, 2 unselected laboratory and 6 laboratory mice from a population bred from winners of fights. Behaviour was recorded when all 16 mice were allowed to fight in all possible pairs in a neutral test box, and when 5 selected mice fought in pairs in the home cages of one or the other. The occurrence of self-grooming, tail rattle and squealing are discussed. Different occurrences of behaviour in the different strains are explained as a result of genetic selection responses.