Whisker trimming behaviour in A2G mice is not prevented by offering means of withdrawal from it

In group-housed laboratory mice whisker trimming (removal of vibrissae) occurs occasionally, but in the A2G strain it is seen almost invariably. We have tested the hypothesis that whisker trimming in A2G mice is not prevented by offering the possibility to withdraw from it. Pairs of male or female mice showing absence of whiskers and/or absence of nasal fur were separated by placing in their cage either one or two wire screens with a 10 mm mesh. Unlike the single screen, the two screens, which were 10 mm apart from each other, excluded nose to mouth contact. After five weeks, whiskers had regrown in mice separated by the double screen, whereas in the pairs separated by the single screen whiskers remained in part absent. This suggests that 2 mice involved in whisker trimming, either actively or passively, co-operate in this behaviour.