Laboratory Mouse Welfare: The Most Common Research Animal

Mice are the most widely used laboratory animal globally, and improving their welfare is one of the highest-impact areas in research animal care.

Key Facts

An estimated 80 million mice are used in research globally each year
Standard laboratory housing prevents many natural behaviors including burrowing and foraging
Mice are nocturnal and often subjected to procedures during their rest phase
Environmental enrichment including nesting material significantly improves mouse welfare
The 3Rs framework requires replacement, reduction, and refinement of mouse use

Welfare Considerations

Standard laboratory housing of mice in small plastic boxes with wood chip bedding and no enrichment prevents burrowing, nesting, exploration, and foraging. Research shows that mice with nesting material show lower anxiety, better immune function, and more consistent experimental outcomes — suggesting that enrichment improves both welfare and science. Nocturnal animals subjected to procedures during daylight hours are handled during their natural sleep phase, adding stress. Simple welfare improvements including nesting material, hiding structures, and red-light handling areas have minimal cost and significant welfare benefit.

What You Can Do

Support funding for research into laboratory animal welfare improvements
Advocate for mandatory enrichment standards for all laboratory animal housing
Support investment in alternatives to mouse models that can answer research questions
Engage with institutions about their implementation of the 3Rs in mouse research