With climate change transforming the American West, an industrious mammal could help mitigate some of the worst of the coming drought and flooding crises. The West is getting drier in the dry season and more prone to flooding in the wet season. Beavers could well be a relatively low-cost part of resiliency efforts. As natural ecosystem engineers, these largest-of-North-America’s rodents “increase water storage in ponds and surrounding floodplains, thus slowing winter flows, increasing riparian and meadow water availability, and extending stream flow up to six weeks into dry summer seasons.”