Lidster, K., Owen, K., Browne, W.J., and Prescott, M.J. Sci. Rep. 9, 15211 (2019)

Mice are a social species, and as such animal care guidelines generally recommend they be group-housed in the lab. But within the confines of a cage, aggression and subsequent injury can occur, particularly among males. Why mice come to blows and how aggressive behavior can be curbed is thus an important welfare concern.

At the front lines are the animal technicians who observe mice day-to-day as part of routine cage checks. Recently, the National Centre for the Replacement, Refinement, and Reduction of Animals in Research in the UK surveyed technicians for incidences of aggression at their facility. Across a sample of 137,580 mice, technicians at 44 facilities noted 788 aggression-related injuries, varying by strain and influenced by several husbandry and housing variables. Details about the results of the survey can be found in Scientific Reports.