What are the abnormal behaviors of mice?

Abnormal behaviors are individual and social actions that are disturbing, destructive, or detrimental to the physiological, psychological, and social well-being of a mouse and/or its cagemates. They are behaviors that differ in pattern, frequency, or context from that shown by most members of a species. Abnormal behaviors are can be thought of as: Unnatural — the behaviors are seen only in captivity, e.g. stereotypy. Unexpected — if the behaviors are seen both in the wild and captivity, they occur under inappropriate circumstances, or are performed to an excessive degree, e.g. infanticide, or ulcerative dermatitis. Nonfunctional — causing self injury and increased mortality, affecting social interactions, growth, and reproduction, e.g. infanticide, ulcerative dermatitis, and barbering. Distress — causing distress to the animal or its cagemates, e.g. infanticide, ulcerative dermatitis, and barbering. Infrequent — seen only in a subset of individuals, e.g. barbering, ulcerative dermatitis, and stereotypy. A maladaptive behavior, such as infanticide, is the behavioral product of a normal animal in an abnormal environment, while a malfunctional behavior, such as stereotypy, barbering, ulcerative dermatitis, is the consequence of an abnormal animal in an abnormal environment.

ICR (CD-1) mice are known to spend prolonged periods of time exhibiting stereotypies with bar-related behaviors such as bar-mouthing. The high tendency for bar-related stereotypies increases with age, peaking in adulthood by taking about 40% of the mouse’s activities. Ts65Dn mice are known to display stereotypic behaviors, including repetitive jumping which takes about 22% of their time, and repetitive twirling which takes up about 21% of their time. About 45% of Ts65Dn mice are expected to display general stereotypy, compared to about 10% of diploid controls. BTBR T+tf/J mice demonstrate repetitive bar-mouthing and repetitive self-grooming, including higher frequencies and duration of paw licking, head washing, body grooming, leg licking, and tail/genital licking. Deer mice perform a lot of backward somersaulting or backflipping and jumping, with these stereotypical behaviors observable at postnatal day 20 and well developed by postnatal day 30. C58/J mice jump excessively and have abnormally high levels of backflipping, with these stereotypies developing by postnatal days 20-21. MECP2 mice display forelimb stereotypies, i.e. repetitive forepaw use, as their main form of stereotypy. DAT knockdown mice demonstrate high levels of self-grooming with rigid and repetitive cephalocaudal grooming patterns. HDC KO mice demonstrate tic-like stereotypy in terms of grooming after exposure to certain stimuli, exhibiting higher levels of grooming than wild-type controls. Bronx-Waltzer mice demonstrate repetitive circling behavior, a form of stereotypy, triggered and prolonged by a stressor.

Stereotypies often occur at particular times of day. The behaviors are as follows: The I column is for recording inactive behaviors The GA column is for recording general activity The M column is for recording maintenance behaviors The B column is for recording barbering The BM column is for recording bar-mouthing The C column is for recording circling The J column is for recording jumping The L column is for recording looping The RT column is for recording route tracing The T column is for recording twirling The W column is for recording wiping. For some research questions it may be useful to divide these numbers by the ‘time active’ (or simply, the number of timeslots in which anything other than 'inactive' was observed). This is particularly true for agonistic interactions, or stereotypies which only occur when the animal is active.