Bison are leading one of the most remarkable ecological comebacks in North American history. For more than a century, the great herds of the American bison were fragmented, broken into isolated groups by roads, fences, and human development across the Great Plains and Yellowstone region. Now, in a powerful wildlife success story, those artificial barriers are being overcome. On their own, bison are instinctively reuniting and reopening ancient migration corridors that had been lost for over 100 years. This isn’t just movement: it’s a profound return to ancestral memory. Large, unified herds are once again flowing across the landscape as they did in centuries past. As they travel, these iconic animals act as masterful ecosystem engineers. Their powerful hooves aerate compacted soil, their selective grazing encourages the growth of diverse native plants, and their dust wallows create seasonal watering holes that benefit countless other species. In doing so, they spread nutrients and help restore the health of the grasslands. By simply allowing bison to roam freely across their historic ranges, nature is showing us that wild ecosystems recover best when their original architects are given the freedom to lead. [Texas A&M University. After 120 Years of Conservation, Yellowstone Bison Are Now a Single Breeding Population. Journal of Heredity]