(1) Seasonal information on dietary composition, forage digestibility and selectivity was collected for bison, cattle and sheep from two treatments representing lightly grazed and heavily grazed pasture. (2) Bison have a greater preference for warm-season grasses and appear to feed less selectively than cattle and in different areas within shortgrass vegetation. (3) Sheep consume fewer grasses than either species. (4) Bison appear to have a greater digestive power than cattle when consuming low protein, poor quality forage, and may also consume greater quantities of forage as compared to cattle. (5) These two mechanisms of feeding strategies may permit bison to exploit more fully than cattle the herbage resources on shortgrass plains.