Facial hair barbering in rats.

Facial alopecia was observed in three of four adult, female, Fischer 344 rats sharing the same cage for 2 months. Alopecia was characterized by irregular areas of hair loss between the eyes, which occasionally extended below the eyes and between the ears. These areas were nonpruritic and were not associated with dermatophytes, pathogenic skin bacteria, or ectoparasites. When the unaffected rat was removed and allowed to cohabit with new cagemates, facial alopecia became apparent in those animals within 6 days, and the hair of the original cagemates grew back within 3 weeks. The alopecia was caused by hair barbering by a dominant female rat.