Material and food exploration by zoo-housed animals can inform cognition and enrichment apparatus design

To robustly study zoo animal cognition and provide effective enrichment, we must provide animals with carefully designed apparatus made from appropriate (safe, attractive, practical) materials. However, all too often, this design phase is overlooked or omitted from the literature. We evaluated how a troop of 12 ring-tailed lemurs (Lemur catta) explored a range of novel materials and whole foods during outdoor social testing. These items were not intended to test cognition or be enriching; rather we viewed them as the potential “building blocks” from which to build our future apparatus. Lemurs preferred to explore wooden surfaces, but had no preference for manipulanda made from different materials. Large amounts of metal and untreated wood should be avoided in the future; metal produced too much heat and glare, and wood was damaged by biting/chewing. Lemurs used one or two hands to explore manipulanda, and simple touching was more common than twisting or pulling. However, lemurs were most likely to explore by smell than touch or by mouth. Social testing preserved “normal” conditions for the lemurs, including natural food stealing and scrounging in high- and low-ranking individuals, respectively. Our findings culminated in the development of a static, low-level cognitive task apparatus, constructed from modular plastic units. We encourage other researchers to report how they develop cognitive and enrichment apparatuses and consider a similar preference-testing approach.