Rats are the most widely used mammals in biomedical research, with welfare needs that are often inadequately met in standard laboratory housing. Refinement practices can dramatically improve their lives.
Laboratory rats live in a world almost entirely shaped by human decisions, making their welfare uniquely dependent on institutional commitment to refinement. Standard housing often fails rats on multiple dimensions: insufficient space for locomotion, absence of burrowing opportunities, social isolation, and lack of enrichment. Pain assessment has historically been poor, leading to inadequate analgesia after procedures. Research now shows that unrelieved pain and psychological stress in laboratory animals can compromise the quality and reproducibility of scientific results — meaning poor welfare and poor science reinforce each other. Group housing, enriched environments, positive reinforcement handling, and systematic pain assessment are all evidence-based refinements that improve rat welfare substantially at modest cost.