Mating takes place from early May to the middle of July but implantation does not occur until about October or November. The young are born from about January to March. The litter size ranges from on to four, but two is most common. In some areas, such as near the Artic coast, the breeding period is considerably longer. In the wild brown bears live from 20 to 25 years.
Brown bears live alone, except for females accompanied by their cubs.
During the breeding season, a male may be with a female up to two weeks for mating. Brown bears are distributed in overlapping home ranges and male home ranges are larger than those occupied by females. Despite their ability for a solitary existence, brown bears congregate at high densities where food is abundant, such as at slamon streams or garbage dumps. In such circumstances, adult males are the most dominant individuals. Brown bears mainly eat vegetation such as grasses, sedges, bulbs, and roots.