The 3Rs framework — Replace, Reduce, Refine — has transformed laboratory animal science. Advanced applications are pushing toward further reductions in animal use and suffering.
Despite decades of 3Rs implementation, significant welfare problems persist in laboratory animal science. Many refinements focus on physical welfare while neglecting psychological needs — social housing, environmental enrichment and positive human-animal relationships. Mice and rats, which constitute 80%+ of research animals, are highly social and cognitively complex. Isolation causes measurable stress and can confound research results. Advancing the 3Rs requires not just technology but cultural change: researchers need training, time and institutional support to implement refinements. The most impactful welfare improvements often cost little — adding nesting material, pair-housing mice, or providing hiding places for rats.