This study hypothesized that: the mode of instruction used at a zoo exhibit and the familiarity (low, medium, high) of an animal to visitors interacts with the amount of knowledge they demonstrate about the animal; a relationship exists between visitors' demonstrated knowledge of an animal of a given level of familiarity and attitude toward protection of the animal; an interaction exists between instructional mode under which information is acquired and degree to which a positive attitude toward an animal is exhibited; and a correlation exists between familiarity-level of an animal and positive attitudes about the animal. Zoo visitors (N=720), aged 16 or older, completed questionnaires consisting of 13 dichotomous-choice items. Data were collected on four consecutive weekends at the Los Angeles zoo. Results, among others, indicate that: visitors learned more with signs or docents (Zoo Teachers); the more familiar visitors are with an animal the more knowledge they demonstrate about that animal; and that docents were found to have no significant impact on visitor knowledge in high/medium familiarity groups, having the greatest impact on visitors when their presentations are for animals of very low familiarity. In addition, attitude was found to be the best predictor of a visitor's knowledge. (JN)