Same Space Different Species: The Influence of Exhibit Design on the Expression of Zoo-Housed Apes’ Species-Typical Retiring Behaviors

摘要

Chimpanzees and gorillas in the wild make nests in which to sleep, made from branches, leaves, and other foliage. Chimpanzees typically make their nests in the trees, by bending over branches, whereas gorillas tend to gather materials to form a nest on the ground. We were interested to know if such species patterns in sleeping elevation would be shown by zoo-living apes. We observed a group of six chimpanzees and a group of four gorillas for two 3-month periods in which they inhabited one of two similar indoor/outdoor exhibits, such that each group was observed in both of the exhibits at different times. Specifically, we considered their location while performing retirement behaviors between 3 and 5 p.m. when they settled down for the night. Both species used the exhibits similarly in that in one exhibit, both species nested in elevated locations, whereas in the other, both species tended to nest on the mulch floor. This suggests that particular characteristics of the exhibit spaces affected where and how the apes retired for the night, while the expected species differences that we know from wild populations were not evident. Understanding how the design of zoo exhibits can affect ape behavior will be useful to those seeking to encourage natural patterns of activity.