Orangutans are highly arboreal primates whose welfare depends on complex three-dimensional environments. Zoo design that meets this need enables positive welfare.
Orangutans in barren, ground-level zoo environments cannot perform the arboreal locomotion fundamental to their nature. Chronic restriction of this behavior causes psychological suffering expressed through stereotypic behaviors. Well-designed zoo habitats with complex three-dimensional structures at multiple heights, combined with foraging enrichment, enable behavioral expression that supports positive welfare.