Singing, tundra, and red-backed voles and brown and collared lemmings convert plant resources to flesh on which a variety of predators depend. Collectively, small rodents may have a profound localized effect on tundra vegetation. Larger rodents include the arctic ground squirrel and Alaskan marmot. Arctic ground squirrels occur primarily on well drained soils along rivers or on slopes. They are commonly observed and can often be a problem at cabins, food caches, and camps.
Wolves occur throughout the park and preserve, traveling in packs or family groups as they hunt.
They are among the earth's largest predators, but in the Brooks Range they feed mostly as vegetarians, eating berries, sedges, hedysarum, and other plants. They also feed on small mammals and may spend hours excavating ground squirrel burrows, locally disrupting much of the ground surface in the pursuit of their prey. The bears will kill moose calves and caribou fawns and occasionally adults. Some scavenging also occurs. Brown bear populations concentrate along most of the major streams and rivers within the park.