The winter coats of American bison—composed of wooly under-hairs and tougher, water-resistant top hairs—make them superbly adapted to harsh weather conditions.These heat-retaining hairs are molted during warmer seasons.
Historically, their coats were valued by native peoples and settlers for their thermal qualities.
Image location: Yellowstone National Park, Montana.
Image credit: © Carra, Lexington, Kentucky. Made publically available via Wikimedia Creative Commons license 2.0.
Meagher (1973, 1986)
Roden et al. (2004)
Van Vuren (1983)