Garner, J. P., Weisker, S. M., Dufour, B. et al. 2004. Barbering (fur and whisker trimming) by laboratory mice as a model of human trichotillomania and obsessive-compulsive spectrum disorders. Comparative Medicine 54(2), 216-224.

In a typical cage of barbered mice, all but one individual will have near-identical patterns of hair loss. The intact individual (the 'barber') is removing hair from its companions. .. Barbers hold down their cage mates [who adopt a defensive posture] and remove hair by plucking with their incisors. Once removed, the hair is often chewed by the barber. .. Four (0.2%) mice appear to barber themselves and their cage mates. .. Of the 13 mice (0.7%) that unequivocally self-barbered, five were single housed. .. Females were approximately one-and-a-half time more likely to barber than males. Breeders were approximately five times more likely to barber than [non-breeders] stock mice. ... The prevelance of barbering increased with age .... leveling off at 20% at 200 days and reaching 21.4% at 300 days.