72 Microseasons of the Pacific Northwest

By late August, Black Bears (Ursus americanus) across the Pacific Northwest have shifted into hyperphagia — a physiologically driven state of near-continuous eating that will continue until they enter their winter dens in November or December. During hyperphagia, bears may spend 20 hours per day foraging and can consume 15,000–20,000 calories daily, gaining 3–5 pounds per day. The goal: double their body weight by denning time, loading on fat that will sustain them through 4–6 months of torpor. In August and September, huckleberries are the cornerstone of the hyperphagia diet for mountain bears in the Cascades and Olympics. A single productive huckleberry patch can hold a bear for days — the animals strip entire bushes methodically, sometimes sitting on their haunches and raking berries into their mouths with one paw. At lower elevations, ripe salal berries, red elderberries, and late blackberries also feature prominently. Bears in the Cascade foothills and Interior valleys raid agricultural areas — orchards and corn fields — as natural berry crops decline. Prime bear-watching locations during hyperphagia include the huckleberry meadows around Indian Heaven Wilderness near Mount Adams, the subalpine berry fields of the Cascades along the Pacific Crest Trail, and meadows on the Olympic Peninsula near Hurricane Ridge and the High Divide. Bears are most active at dawn and dusk, when light is low and temperatures are cool. A bear in hyperphagia may be so intent on eating that it's less alert to human presence than at other times of year — but a surprised or food-stressed bear can be unpredictable, and visitors should maintain distance, make noise while hiking, and carry bear spray in prime habitat. The frantic pace of late-summer feeding is a visible and well-documented signal of the approaching seasonal transition.