Mice are by far the most commonly used laboratory animal, yet recognition and management of pain in mice remains poor across much of the research sector.
Pain in mice has been systematically underestimated and undertreated because mice are small, their pain signals are subtle and assumptions of lesser sentience have historically reduced welfare rigour. The Mouse Grimace Scale has removed the excuse that mouse pain is undetectable. What remains is the institutional and cultural challenge of ensuring that pain recognition tools are actually used and that analgesics are routinely provided for painful procedures. Group housing, environmental enrichment, and better-trained researchers who recognise and respond to pain signals are welfare improvements that cost little and improve both animal wellbeing and research quality.