Finally, the shaman sometimes acquires his powers through seeking for them rather than by having them thrust upon him during a dream or vision. This of course is a common procedure in the Plains and in part on the North Pacific Coast. Among the Yurok of the lower Klamath, for instance, the person whom the spirits have visited in dreams, ascends high peaks where he spends one or more nights until he has acquired his powers. Among the Wiyot of Humboldt Bay there are similar beliefs. In the same Northwestern region a man who wishes to be fierce, strong, and invulnerable swims at night in lakes inhabited by monsters or thunders. From these, if his courage is sufficient to await and endure their presence, he receives the desired powers. This practice of bathing in lonely lakes closely recalls the custom prevalent along the Pacific slope for some distance northward, and within California it is probably not strictly confined to the Northwestern culture area. On the whole, however, this deliberate method of acquiring shamanistic power is not common, nor, as has already been stated, would it be in accord with the generally lower intensity of religious feeling among the California Indians as compared with those of most other parts of the continent. The Northwestern area is not only exceptional in being the principal one within the state where this deliberate seeking of shamanistic power is prevalent. The conception of a guardian spirit is much less clearly defined among the Northwestern tribes, with whom the possession of "pains," the small material objects which cause disease, rather than of true spirits, seems to be what is generally associated with shamanistic power. As already stated, shamanism forms a much less important part of religion as a whole in the Northwestern area than elsewhere, and it is in accord with this fact that the majority of the shamans, and those supposed to be most powerful, are women.