Measurements of visitor behavior were collected at selected exhibits in 13 zoos throughout the United States. Percentage of visitors who stopped at each exhibit and the duration of visitor viewing time were obtained at exhibits of various species. Visitor behavior was found to correlate with both the characteristics of animals (animal activity, size of species, presence of infant) and the architectural characteristics of the exhibits (presence of visually competing exhibits, proximity of visitor to animal, visibility of animals, physical features of the exhibit). These finding have several implications for designing zoo exhibits.