At McNeil River Falls, the largest concentration of brown bears occurs annually. Biologists have observed more than 60 bears at one time, attracted by spawning salmon. While in this state, their body temperatures, heart rate, and other metabolic rates are reduced. Their need for food and water is eliminated. In areas with relatively warmer winters, such as Kodiak Island, a few bears may stay active all winter.
Pregnant females are usually the first to enter dens in the fall.
These females, with their newborn cubs, are the last to exit dens. Adult males, on the other hand, appear to enter dens later and emerge earlier than most other bears. Bear hunting seasons are held in both spring and fall in some areas but only in fall in other areas. Cubs and females with offspring may not be killed. Bear meat should be thoroughly cooked to prevent contracting trichinosis, a parasitic disease which may be fatal to man.