Research Animals

Mouse and Rat Welfare: Beyond the Laboratory

The welfare of mice and rats in research contexts depends on housing, handling, and experimental procedures that interact to determine overall welfare status.

Key Facts

Mice are the most commonly used laboratory animal globally with over 100 million used annually
Standard housing often denies mice burrowing substrate, nesting material, and running wheels
Nest building is a strongly motivated behavior in mice used as a welfare indicator
Social housing is essential for mice and rats yet single-housing for experimental reasons is common

Welfare Considerations

Laboratory mice and rats in standard housing cannot burrow, nest fully, or run adequate distances. These are not minor deprivations but frustrations of strongly motivated behaviors. Burrowing and nest building are so motivationally important that mice choose to perform them when given the opportunity even in preference to food. The welfare cost of standard housing affects experimental results as well as animal welfare.

What You Can Do

Support research institutions that implement enrichment as their default housing standard
Advocate for funding bodies to require welfare standard housing as a condition of ethics approval
Support development of validated welfare assessment tools for laboratory rodents
Donate to organizations developing and validating non-animal research alternatives