While most bears will run from a human, a female with cubs should be respected and on rare occasions might actually attack if she feels her young are in danger. Bears find food mainly by scent. They are opportunistic feeders, with a largely vegetarian diet. Bears drink water frequently, and in hot weather they wallow in streams. In autumn, bears eat heavily to fatten themselves for winter.
Some bears line their dens with bark, grasses or leaves.
Females often select more sheltered sites than males. Females with first-year cubs den with their young. In winter, bears den up and become dormant. They lapse into and out of a deep sleep, from which they may be roused. Body temperature is not drastically reduced.