Whisker trimming in mice.

Whisker trimming is extremely common in strain A2G mice, with an incidence which progresses with age. Over 75% of cages containing 2-3 mice have 1 or more active trimmers by the time the mice are about 60 days old. When male A2G mice were housed with mice of other strains there was a tendency for trimming to occur most in cages where the A2G male was socially dominant (as judged by a tube test). The number of animals per cage did not seem to influence this behaviour. In groups of male mice there was usually I with untrimmed whiskers, presumably because he was socially dominant. However, with females there were always several active trimmers. There was some evidence that when females became pregnant they were able to resist whisker trimming by their mates.