From the tiniest mouse to the largest grizzly, mammals of all shapes and sizes find a home in national parks. Some parks were set aside so we could observe the magnificent mammals. Catching a glimpse of them in their natural habitat can be a thrilling experience. Or a reminder of just how tough life in the wild can be. Discover stories of survival on land and sea. Explore how we study and manage hundreds of different species. Learn more about the lives of mammals in our national parks.