Characterization of a Jumping Stereotypy in Gerbils (Meriones unguiculatus) and Assessment of Opaque Tubing Enrichment on Stereotypies and Breeding

Mongolian gerbils can develop stereotypic behaviors, including corner digging. At our institution, gerbils also engage in repetitive corner jumping, which we sought to characterize as a potentially novel stereotypy in gerbils. We then attempted to mitigate this behavior by mimicking the natural habitat by adding intracage environmental complexity. Seventeen gerbil breeding pairs were video recorded in their home cages during the light cycle. Repetitive corner jumping and digging were compared between different times of day to assess when the behaviors occurred and whether they were temporally associated. To determine whether we could reduce the incidence of stereotypic behaviors, we tested a straight tube or 1 of 3 angled opaque tubes in different orientations, which were fitted to the gerbils' preexisting opaque nesting box. Behavior was assessed at baseline and at 1, 4, 8, and 12 wk to evaluate opaque tube placement as an intervention. In addition, breeding efficiency, valuated as the number of gerbil pups born and weaned per breeder pair, was compared with pre- and poststudy data. The number of corner jumps was highest at the end of the light cycle and the majority were associated with corner digging. After placement of the enrichment tubes, an initial increase in corner digging behavior was observed and persisted throughout the study period. The opaque tubes were not associated with significant changes in corner jumping. After adjusting for age, the addition of opaque tubing to gerbil breeding cages was not associated with significant changes in breeding efficiency. The addition of opaque tubing did not effectively address concerns about stereotypic behaviors and was associated with a chronic increase in stereotypic corner digging among breeding gerbil pairs.