The Northwest's abundance of resources allowed indigenous people to develop a rich culture of artistic, religious and ceremonial traditions. The region's exclusively male artists specialized in distinctive carvings that depicted animal, monster and human forms. The figures represented supernatural beings whose spirits gave the artist permission to render their likeness. An animal species was distinguished by one or two prominent features. For example, the bear was characterized by a stubby snout, large teeth and a protruding tongue, while the beaver was portrayed with protruding teeth, a cross-hatched tail and a stick between its forepaws. By borrowing the features of more than one species, a monster could be depicted. Carvings were painted in red and black and sometimes incorporated into elaborate masks. When white people introduced iron tools, totem poles were created. These tall, cylindrical objects were carved from a tree trunk and indicated their owners' prestige. The religion of the Northwest Native Americans was closely tied to nature. They believed that animal and human lives were inextricably intertwined. Animals were intelligent, willful beings and should be treated with respect. Other beliefs involved an afterlife, which was a continuation of earthly life, a sense of the natural order as slippery and fluid, and various myths that explained creation. Shamans were important to the religion and cured disease by realigning spiritual elements. Shamans honed their skills by going on frequent retreats and practicing sexual and dietary abstinence. Much ritual activity focused on food. For example, an elaborate salmon festival was held to honor the first catch of the year. The fish were treated as chiefs of high rank in the hope that their souls would spread the news of their good fortune and attract other fish to be harvested. Another key ceremony was the hamatsa dance. Performed by the Kwakiutl tribe in the winter, the ritual dealt with the hamatsa, a human who had been carried off by spiritual beings. After learning the ways of the spirits, the hamatsa escaped and returned to the human realm, only to find that human expression was too weak for his new divine energy. The dance depicted the hamatsa going berserk, requiring a dozen tribe members to restrain him. Though Potlatches were more secular by nature, they were also important rituals that dealt with wealth and social organization.