The ŭtiyíņ became medicine men by instruction, not by supernatural agencies. The two other classes acquired their power solely through dreams. When the old men of a village deemed it advisable to have a new ŭtiyíņ or "sucking doctor", either because of the death of some of the shamans or because of their waning power, the active and the retired shamans selected a promising young man. With his consent, they took him away from the village to a solitary place in the hills. The one who had been selected to be his instructor and "father" would pray and instruct the young man in the secrets of the medicine men.