Wagner, J. L., Hackel, D. B., Samsell, A. G. 1974. Spontaneous death in rabbits resulting from gastric trichobezoars. Laboratory Animal Science 24, 826-830.

Hairball formation in humans occurs most frequently in emotionally disturbed females below the age of 30. It is possible that individual caging of rabbits over long periods of time could affect their psychological health and bring about abnormal grooming habits, thus contributing to hairball formation.