American Bison (Bison bison) Fact Sheet: Diet & Feeding

• Bison are grazers; feed mostly on grasses.
• Winter/summer diets differ in free-ranging populations. (Grizmeck 1990)
  • Add lichens and mosses to diet in winter.
• When feeding on natural vegetation select many different grass and a few other plant species, varying with local habitats (Peden et al 1974)
  • Blue gramma (Bouteloua gracilis), sand dropseed (Sporobolis cryptandrus) little bluestem (Andropogon), windmill grass (Chloris), wild oats (Avena), wheatgrass (Agropyron), and Bromus Hierchloe, Elymus, Koeleria, Stipa, Phragmites, Distichlis, Hordeum, and Carex.
  • In Arizona bison ate 71% saltbush (Atriplex sp.) (Peden et al 1974)

• Ruminant digestive system; four chambered stomach
• Compared to cattle, bison extract more nutrition from low protein, highly fibrous plants. (Hawley 1981).
• European bison have more browse in their diet in the wild. (Peden et al 1974)
• Because American bison males in the wild lived mostly apart from the large herds, they were able to select the better-quality food and grow to very large size. (Guthrie 1990)

Guthrie (1990)
Hawley et al. (1981)
Peden et al. (1974)