Bison are adapted for migratory grazing by having low-slung heads, muscular limbs and necks, digestive systems that are able to extract nutrients from fibrous vegetation, hard hooves for rapid travel and woolly coats for insulating against cold prairie nights. They also tend to eat during the coolest parts of the day, early morning and evening, to avoid overheating under the prairie sun.
While bison are large animals and can eat up to 30 pounds of grass per day, they constantly move as they eat. This prevents the territory they roam over from becoming overgrazed and barren. Their scat serves as fertilizer, growing new vegetation in its place.
Bison, despite their size, are able to run up to 30 miles per hour if they are faced with a threat. Their tendency to herd in massive numbers protects individuals from being picked off by predators. If cornered by a predator, the bison has large horns to ward them off. The horns are powered by a massive shoulder hump that is formed by a large hook of vertebrae to which is attached powerful neck and shoulder muscles. This makes the bison's horns a particularly formidable weapon.
Bison only need to drink once a day, which means they do not have to stay near a water source while grazing. They will even eat snow if liquid water is not available.