Whether cats should be kept indoors or have outdoor access is one of the most contested welfare questions in companion animal science. Evidence supports nuanced approaches that balance different welfare dimensions.
The indoor/outdoor cat welfare debate involves genuine trade-offs between individual welfare and population-level impacts. For individual cats, outdoor access allows expression of natural behaviours — hunting, territory patrol, social interaction and exploration — but exposes them to road traffic, disease, predation and territorial conflict. For wildlife, outdoor cats are one of the largest sources of human-associated bird and small mammal mortality. Evidence-based approaches include catio (enclosed outdoor areas) provision, microchipping and neutering, dawn/dusk confinement when birds are most active, and indoor enrichment programmes that address behavioural needs. Neither extreme (permanent outdoor free-roaming or permanent small indoor confinement without enrichment) represents optimal welfare.