Denali National Park and Preserve is located in Interior Alaska and contains Denali (Mount McKinley), the highest mountain in North America. Denali is home to a variety of Alaskan birds and mammals, including a healthy population of grizzly bears and black bears. Herds of caribou roam throughout the park. Dall sheep are often seen on mountainsides, and moose feed on the aquatic plants of the small lakes and swamps. Despite human impact on the area, Denali accommodates gray wolf dens, both historic and active. Smaller animals, such as hoary marmots, arctic ground squirrels, beavers, pikas, and snowshoe hares are seen in abundance. Foxes, martens, lynx, wolverines also inhabit the park, but are more rarely seen due to their elusive natures.