Rats are highly intelligent and social laboratory animals whose welfare significantly exceeds legal minimums when appropriate enrichment and social housing are provided. Evidence guides what works best.
Laboratory rats are intelligent social animals capable of remarkable cognitive achievements including empathy-like behavior and cooperative problem solving. The welfare implications of this cognitive complexity are profound: rats in impoverished isolated environments are denied the social bonds, cognitive engagement, and environmental complexity they are neurologically equipped to experience and value. Social housing of compatible pairs or groups is the single most impactful welfare improvement for laboratory rats and is achievable without compromising most research applications. Environmental enrichment adds further welfare benefit by engaging cognitive capacities that standard laboratory housing does not address. The 3Rs framework requires these improvements, and institutions that implement them typically report improved welfare alongside better behavioral phenotyping because enriched rats are more physiologically normal.