It may be surprising to us now, but the taxidermists who filled the museums, zoos, and aquaria of the twentieth century were also among the first to become aware of the devastating effects of careless human interaction with the natural world. Witnessing firsthand the decimation caused by hide hunters, commercial feather collectors, whalers, big game hunters, and poachers, these museum taxidermists recognized the existential threat to critically endangered species and the urgent need to protect them. The compelling exhibits they created—as well as the scientific field work, popular writing, and lobbying they undertook—established a vital leadership role in the early conservation movement for American museums that persists to this day. Through their individual research expeditions and collective efforts to arouse demand for environmental protections, this remarkable cohort—including William T. Hornaday, Carl E. Akeley, and several lesser-known colleagues—created our popular understanding of the animal world and its fragile habitats. For generations of museum visitors, they turned the glass of an exhibition case into a window on nature—and a mirror in which to reflect on our responsibility for its conservation.