The herbivore’s return to Yellowstone is restoring ancient patterns and reshaping the landscape from the ground upYellowstone national park is witnessing a striking ecological recovery, driven by the return of one of the US’s most iconic species. Yellowstone’s bison are providing scientists with rare insights into how large herbivores influence ecosystems. Yellowstone’s bison offer scientists rare insights into how large herbivores influence ecosystems. Such corridors would reconnect fragmented habitats, reduce the risks of inbreeding, and help ensure that bison populations remain healthy and adaptable. These factors limit the potential of large-scale rewilding, even as the ecological benefits of natural grazing become clearer.