Rats are highly social, intelligent animals who suffer severely from isolation and whose welfare needs are frequently unmet in typical companion keeping, yet they make exceptional companions when properly housed.
Rat welfare is characterized by the gap between their reputation — shaped by pest control associations and their use in research — and their actual cognitive and social richness. Rats are among the most cognitively sophisticated companion animals available, capable of learning complex behaviors, showing empathy, and forming deep bonds with their keepers. Against this cognitive backdrop, housing rats alone is particularly welfare-harmful: a highly social and intelligent animal experiencing isolation is suffering in a way that their apparent behavioral placidity does not reveal. Pair or group housing with appropriate space, varied substrate, and enrichment transforms the welfare of companion rats at modest cost.