How modern zoos use enrichment to support psychological welfare of animals, the evidence base for different approaches, and ongoing challenges.
Environmental enrichment in zoos has moved from an occasional novelty to a welfare requirement in accredited facilities. Good enrichment programs are species-specific, regular rather than sporadic, and evaluated for actual behavioral impact rather than just provided and assumed to work. The challenges are significant - large, cognitively complex animals like great apes and elephants require extremely varied and sophisticated enrichment to prevent boredom and stereotypies. Keeper time and resources limit enrichment frequency. Nevertheless, well-designed enrichment programs can meaningfully improve the psychological welfare of zoo animals.