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)
Feeding
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)
Page Citations
Guthrie (1990) Hawley et al. (1981) Peden et al. (1974)