Effectively communicating environmental issues to motivate visitors' behavior is critical for zoos to accomplish their missions. We examined the relationship between zoo visitors' environmental concern and agreement with messages framed by environmental concern. Findings from two zoos (N = 298; N = 400), using two message formats, provided nearly identical results suggesting visitors have high levels of biospheric concern and, in general, agree more with statements framed by biospheric concern. Biospheric messages are likely to be more useful for evoking environmental concern and related conservation behaviors among zoo visitors. Zoos should consider technology such as smartphone applications to deliver targeted environmental concern framed messages to onsite visitors. More research is needed to determine preferred frames of communication away from zoo grounds.