Fauna include brown bears, black bears, muskoxen, moose, Dall sheep, timber wolves, wolverines, coyotes, lynxes, marmots, porcupines, river otters, red and Arctic fox species, beavers, snowshoe hares, muskrats, bald eagles, golden eagles, peregrine falcons, ospreys, great horned and northern hawk-owls. More than half a million caribou, including the Central Arctic, Western Arctic, Teshekpuk, and Porcupine herds, migrate through the central Brooks Range twice yearly, traveling north in summer, and south in winter. Caribou are important as a food source to native peoples. The park is the northernmost range limit for the Dall sheep. About 132 brown bears reside in the park and preserve, based on a density of about one bear per .