Their summer food consists of grasses, forbs, sedges, and low shrubs. In winter, when these are not available hares switch to the needles and bark of conifer trees, and the leaves of willow and alder are also forage items. They are crepuscular and nocturnal, and prefer dense cover for protection. No definite nests are built, but depressions are made under shrubs and sometimes lined with grass, fur, and needles. Breeding occurs in February through June with a gestation period of 35-37 days.
Males are intolerant of each other.
During breeding season, they will fight with conspecific males. Major predators are bobcats, coyotes, great horned owls, domestic dogs and cats. Their population abundance varies and tends to be cyclic. About a third of their potential range is at extreme fire risk.