Domestic rats are highly intelligent, social animals whose welfare depends on appropriate companionship, environmental complexity and regular human interaction.
Companion rat welfare is frequently inadequate due to housing in small cages without companions and insufficient enrichment. The social deprivation of single housing causes distress that manifests in increased stress hormones and abnormal behaviour. Their short lifespan means health problems including tumours appear relatively early and require prompt veterinary attention. The combination of strong social needs, high intelligence and medical susceptibility makes rats rewarding but demanding companion animals.