Effective zoo enrichment requires deep knowledge of each species natural history — a rubber ball for a tiger is not enrichment, but a scent trail of prey hormones may occupy it for hours.
Species-specific enrichment design requires investment in both wildlife science and observational creativity. The same budget spent on generic enrichment for every species will produce far less welfare benefit than the same budget spent on species-appropriate interventions. An otters welfare improves most from water and foraging opportunities; a gorillas welfare improves most from complex social groupings and browse variety; a tiger benefits most from olfactory enrichment and prey-related stimuli. Zoos that invest in keeper knowledge of species natural history produce better enrichment and better welfare outcomes than those that focus only on facilities.