Thirty-seven species of mammals have been identified at Indiana Dunes National Park. Four other species are thought to inhabit the park, but have not been documented: the northern long-eared myotis (Myotis septentrionalis), the Indiana bat (Myotis sodalis), the hoary bat (Lasiurus cinereus), and the southern bog lemming (Synaptomys cooperi)
Common mammals seen by visitors and residents include the eastern cottontail, the eastern fox squirrel, the white-footed mouse, the white-tailed deer, and the meadow vole. Extirpated mammals include the common porcupine (Erethizon dorsatum), the gray wolf (Canis lupus), the red wolf (Canis rufus), the black bear (Ursus americanus), the fisher (Pekania pennanti), the cougar (Puma concolor), the Canada lynx (Lynx canadensis), the bobcat (Lynx rufus), the elk (Cervus canadensis), and the American bison (Bison bison). There are two threatened or endangered species in the dunes. The American badger (Taxidea taxus), on the Indiana threatened list is known to inhabit the area. The Indiana bat (Myotis indiana), on the federal endangered list is presumed to inhabit areas of the dunes. Recent records, documented photographically, indicate that North American river otter (Lontra canadensis) and bobcat (Lynx rufus) began returning to the area in 2011 and 2018, respectively.
List of mammals documented in the Dunes
Habitats
While this article breaks out mammal communities by habitats, one of the problems you'll encounter in the Dunes community is that the habitats are in flux. Razed Residential areas are slowly returning to the habitat of the surrounding area, whether that is a wetland hummock, or a savanna. At Mount Baldy forested areas are becoming open sand. While the process may take years, an area that once hosted a community of plants and animals may change in your lifetime.
Barren ground
Barren ground consists of open sand on the beaches and blowouts. Barren grounds are about 4% of the dunes areas and occur mostly along the beaches. Because of the scarcity of plants there are no permanent mammals living in the area. The normal process is for animals to hunt on the beach at night. Some animals will live in the scattered clumps of plants that may remain or return to the blowouts. Evidence of animals in the barren areas is usually done through their tracks. Animals appear to go to the beach to feed and/or drink. In the blowouts, evidence of mammals is found near the clumps of grass (marrain grass and sea rocket).
Species found
Beaches: Virginia opossum, raccoon, and prairie deer mice and white-tailed deer. Blowouts: masked shrew, prairie vole, and meadow voles.
Prairie
About 4.4% of the area of the dunes is prairie. Three-fourths of that is dry prairie, the remainder is wet prairie.
Dry prairie
Dry prairie primarily is along the front of dunes. It is easily identified by open sand with stands of marram grass and sand reed. The increased plant life over the barren sand provides shelter for small mammals. Little bluestem grass may be mixed in or it may form dense clumps among the dunes. The plots with little bluestem grass often had a greater variety of plant species, especially when away from the lakeshore.
Species found
Marram grass, sand reed, little bluesteam dominated prairie: Prairie deer mice, white-footed mice, meadow voles, thirteen-lined ground squirrels, northern short-tailed shrews, and eastern cottontails. The prairie mice are the only small mammal that increase in numbers with less plant cover. Voles thrive only with good plant cover. When short-tailed shrews use dry prairies only where they abut wetter areas.
Marram grass, and sand reed only prairie: Prairie deer mice, white-footed mice, prairie voles, ground squirrels, eastern cottontails, and northern short-tailed shrew.
Little bluestem grass dominant areas
Prairie deer mice, white-footed mice, northern short-tailed shrews, thirteen-lined ground squirrels, and eastern cottontail.
Signs foundeastern cottontail, the red fox, white-tailed deer, domestic dog and the long-tailed weasel. Sign have been seen that may be the southern bog lemming, but no animal itself has been found to confirm its presence. The bog lemming stays pretty much in bogs or wet areas. It does have a broad range of habitats around wetland areas. The thirteen-lined ground squirrel stays mostly in mowed areas, i.e., lawns, pastures, and roadsides. There discovery may indicate that they lived in the dry prairie before settlement created artificially maintained (mowed) spaces.