As conservationists confront an accelerating extinction crisis, zoos are emerging as potentially significant players in the effort to protect global biodiversity, a role that will likely intensify in the coming decades. It’s an agenda, however, that raises a number of ethical and practical questions as zoological parks seek to balance a growing conservation mission alongside their traditional recreation and entertainment pursuits. Many of these questions were first addressed in Bryan Norton’s anthology, Ethics on the Ark, a milestone in applied ethics and zoo conservation published in 1995. In the decades since Norton’s book appeared, the function of zoos as conservation educators and as centers of public transformation has come into sharper focus, with new fields such as conservation psychology measuring the impact of the zoo visit on public perceptions, attitudes, and conservation behaviors. In this chapter, we explore some of this recent empirical work examining zoo visitors’ experiences and argue that Norton’s early writing in environmental ethics and conservation, particularly his notion of “transformative value,” offers a philosophical grounding for understanding the ethical potential of encounters with zoo animals. We close the chapter by discussing some of the challenges and tensions that emerge when Norton’s argument, which was originally presented as a justification for protecting wild biodiversity due to its ability to “transform” consumer preferences to more ecologically enlightened attitudes, is adapted to the zoo setting.