From Cheryl Shearar's "Understanding Northwest Coast Art":
Bear is one of the most prevalent figures in crest and shamanic art, as well as in myths. It is considered to be a close relation of human-kind, perhaps because of physical characteristics such as size, appearance, and expression, and behaviours such as standing on two hind legs, gathering plants and berries, fishing and nurturing young.
As a close relation to humans, the bear is a link between the human and non-human animal realms, as well as, between the ordinary natural realm and the supernatural. Because of their strength and fierceness, bears are frequently the guardians, protectors and helping spirits of warriors.