Gorilla Kept Stacking Tires Every Morning — Then His Caretaker Finally Figured Out Why

The tires, provided as part of the primate’s enrichment, served as a form of mental and physical stimulation for Koko. Enrichment is essential for captive animals, ensuring they have the ability to express natural behaviors, increasing their physical activity, and alleviating potential anxiety or stress. Yet, for Koko, these tires had taken on a unique meaning.