Domestic rats are among the most cognitively sophisticated companion animals and require complex social environments and enrichment - welfare science shows many kept rats are significantly understimulated.
Rat welfare research has been transformative for our understanding of social cognition and empathy in small mammals. The evidence that rats help trapped companions and show other-regarding behaviour has ethical implications for how we house and treat them. Group housing is essential - solitary rats show elevated corticosterone and anxiety behaviours that are ameliorated by companions. Cognitive enrichment including puzzle feeders, novel objects and training exercises addresses their high intellectual needs. Many pet rats are housed in small, barren cages with insufficient social contact, representing a significant welfare gap between evidence and practice.