Zoos are an important and popular source of recreation. The American Zoo and Aquarium Association reports its members had 134 million visitors in 1998. This attendance figure is more than the professional baseball, basketball and football attendance combined.

Zoos, and similar facilities, such as aquariums, have a long history of providing recreational opportunities. For many years, these institutions were part of the National Recreation and Park Association (NRPA) . Eventually, the need to expand their emphasis of the issues of conservation, science, and education resulted in a split from the NRPA in 1971 to form the American Association of Zoological Parks and Aquariums Association (AAZPA). The AAZPA recently changed its name to the American Zoo and Aquarium Association (AZA). Even with the separation from the NRPA, the AZA charter includes an objective for participating members to promote recreational opportunities for all visitors (Boyd, 1993).