Lukas, K. E., Hoff, M. P., Maple, T. L. 2003. Gorilla behavior in response to systematicalternation between zoo enclosures . Applied Animal Behaviour Science 81, 367-386.

Gorillas were more likely to increase exhibit use and visibility to zoo visitors during a 4-day novel phase compared to subsequent days in the exhibit. ..Regularly alternating gorillas between zoo exhibits is a form of environmental enrichment that can increase gorillas' use of exhibit space and increase activity level.