The daily activity of bison is much like that of domestic cattle. The chief feeding periods are early morning and late afternoon, with midday given over to cud-chewing, siesta, and wallowing. Normally, nighttime is a period of rest. Formerly, the plains bison migrated seasonally, going south as far as Florida and Texas in winter, and northward again in summer. Their normal gait is a plodding walk, which may break into a swinging trot or, when frightened or angered, a stiff-legged gallop.
Plains bison are predominantly grazers, feeding chiefly on grasses and secondarily on forbs.
Browse species contribute slightly to their menu. Because of this, competition between bison and domestic cattle for range forage is so great that we cannot afford, for economic reasons, the return of the bison to anything like its former numbers. The period of rut is July and August. The animals are promiscuous in mating habits but usually only the large, mature bulls do the breeding. Young and undersized bulls are driven from the herd to linger on the outskirts and await with anticipation the opportunity to participate whenever the herd bull is off guard.