Stereotypic behaviors in laboratory mice — including wire-gnawing, bar-chewing, and repetitive jumping — are reliable indicators of chronic welfare compromise requiring environmental intervention.
Stereotypic behaviors in mice are not quirks or habits — they are welfare signals indicating that animals are experiencing chronic frustration of motivated behavioral drives. The standard laboratory cage, with its bare floor, few conspecifics, and minimal stimulation, creates the conditions for stereotypy development in a high proportion of housed mice. Once established, stereotypies persist even after enrichment is provided, making prevention through adequate housing from the start far more effective than remediation. Researchers should treat stereotypy prevalence as a welfare outcome measure and routinely monitor and report it alongside experimental endpoints.