The bears eat berries, roots and rodents in late summer and fall, in preparation for winter denning. The bears have poor eyesight, but have a keen sense of smell and are always searching for something to eat. Some bears enter their dens in late October. Pregnant sows and sows with cubs are the first to hibernate. The dens are just large enough for the bears to fit into comfortably.
Some bears excavate their den and others use natural cavities.
Some boars remain active and outside all winter. Most bears come out in late March and April. An estimated 40,000 brown bears live in Alaska. The bears usually have 2 or 3 cubs and the cubs will remain with the sow for 2 or 3 years. Cubs weigh less than a pound when born and usually weigh 15 pounds or more when they leave the den with the sow.