Indoor cats require systematic environmental enrichment to express natural behaviours and maintain positive welfare states.
Indoor environments without enrichment create chronic frustration through inability to express hunting, territorial, and exploratory drives. Cats in unenriched environments show higher stress markers, increased inter-cat conflict, and health problems including feline idiopathic cystitis linked to stress. Systematic enrichment — rotating toys, food puzzles, vertical space, window access, and regular hunting play sessions — significantly reduces stress indicators and improves welfare. Environmental enrichment is the most accessible and cost-effective welfare intervention for indoor cats.