McMillan BR, Cottam MR, Kaufman DW. Wallowing behavior of American bison (Bos bison) in tallgrass prairie: an examination of alternate explanations. The American Midland Naturalist. 2000;144:159 -167. doi:10.1674/0003-0031(2000)144[0159:WBOABB]2.0.CO;2.