Why does Elder Uncle agree to move into the abandoned bear den in spite of his reservations?

Elder Uncle is concerned about moving to Wowumnupo because no Yahi has ever lived in an abandoned bear den. He is also concerned about whether or not they would actually be able to build a village on the wall of a canyon. In spite of these concerns, he agrees to move because no saldu would ever believe that a village could exist there. He knows that none of the animals (i.e. horses or dogs) would ever be able to travel up the side of the canyon. Even though the location is inconvenient, the safety that it offers convinces Elder Uncle to bring the family to the cave.