Decades of research into enrichment for zoo animals has produced an evidence base showing what works, what does not, and how to design enrichment that truly meets welfare needs.
Zoo enrichment science has matured significantly from the early days of simply providing toys and puzzles. We now understand that effective enrichment must be species-appropriate, unpredictable, and cognitively or physically challenging in ways that match natural behaviour. A leopard that can hide and ambush - even a rubber ball - is engaging natural predatory behaviour in a welfare-positive way. A parrot solving a foraging puzzle to access food is doing something analogous to wild foraging behaviour. Poor enrichment - objects that are used once and ignored, food presented without challenge, or enrichment that is inappropriate for the species - fails the welfare purpose entirely. The best zoos evaluate enrichment effectiveness continuously using behaviour data, and modify programmes based on evidence of use and welfare benefit.