Matsuzawa, T. 2020. WISH cages: Constructing multiple habitats for captive chimpanzees. Primates 61(2), 139–148.

This article aims to introduce environmental enrichment for captive chimpanzees in Japan in a historical context. It describes the most recent endeavor of constructing huge cages and connecting multiple habitats. The Ai Project, a series of studies into the mind of chimpanzees, is based at Kyoto University PRI and started on November 10, 1977. The 42-year-old project has produced many important scientific findings (Matsuzawa et al. 2006) and was the driving force behind promoting environmental enrichment for captive chimpanzees. See the website for the on-going project: The most recent endeavor involves what we call “WISH” cages, which have been constructed in PRI and KS. The idea is to provide chimpanzees with two huge cages adjacent to their existing outdoor compound. These large structures are also interconnected by a corridor. The chimpanzees can freely use these multiple habitats by moving between them at will. This setting simulates the fission–fusion dynamics of chimpanzee groups in the wild. The huge cages are also equipped with a computer-controlled touch panel system for cognitive tests, which serve as an additional enrichment device giving extra feeding opportunities. Previously, cognitive testing was conducted by isolating one or a pair of chimpanzees in an experimental booth located away from their daily living space. This conventional practice was challenged by the WISH cages, which allow the chimpanzees to access food at any time of day or night. By paying attention to the two kinds of freedom, eating and moving, the WISH cages provide us with a glimpse of future approaches to cognitive studies in captivity: social cognition in an enriched environment. In short, efforts to enrich the captive environment can and should go hand-in-hand with sophisticated cognitive studies. In future I hope to see many other facilities following the concept of the WISH cages, connecting multiple habitats and providing more freedoms for captive chimpanzees.