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An approach for relating fitness to foraging activity is described for 2 adult female grizzly bears (Ursus arctos) in coastal British Columbia. During berry season both bears roamed widely (seasonal home ranges of 3932 and 3565 ha) using at least 10 different species of berries in widely divergent habitats. Bears spent 62%-69% of their time in habitat types used for feeding. Habitat use by the bear with the smaller home range was correlated with food quantity and quality (rs = 0.79, P < 0.05); that of the more widely ranging bear was not (rs = 0.11, P > 0.1). During the berry season, both bears relied heavily on berries, but their diets differed. During the 3-year study, reproductive success of the more efficient bear (smaller home range, feeding activity correlated with food quality) was greater than that for the less efficient bear (3 vs. 2 cubs). These observations are discussed in terms of foraging theory. We conclude that 1 bear appears to be optimizing, but both bears could be satisficing.