One of the roles of the modern zoo is to provide environmental education. Zoo visitation comprises primarily family groups seeking to spend time together. There is potential for tension between message and audience expectation as zoos seek to raise awareness of the effects of irresponsible human behavior on the environment. This may unsettle family visitors. This study explored levels of tolerance of the zoo audience to a disturbing exhibition covering broad environmental themes. Results showed that participants were prepared to reflect on the content and at times feelings were sufficiently strong for zoo visitors to challenge one another's beliefs. The delicate positioning of zoos as environmental education providers is discussed. (Contains 6 figures and 1 table.)