Naturalistic enclosure design in modern zoos substantially improves animal welfare by enabling expression of species-typical behaviors.
Zoo animals in concrete and steel enclosures without naturalistic complexity show high rates of stereotypic behavior, reduced activity diversity, and physiological stress. Naturalistic enclosures with varied substrate, vegetation, water features, and olfactory complexity enable behavioral expression that is impossible in barren environments. Evidence-based design improvements have substantially improved welfare in facilities that have transitioned from traditional zoo design.