The coming of death and life - from Navajo mythology

From Aileen O'Bryan: Navaho Indian Myths

Now the earth, which had been stretched, became solid, and the rivers flowed. Trees grew along the banks of the rivers, and flowers grew at the foot of the mountains with the rocks and the cliffs and other trees above them. The Mother Earth was very beautiful.
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But just when everything on the earth was good and beautiful the people saw the first death. They remembered what the Sun had said. He had claimed the lives of all the living in payment for his light. The people wondered where the dead would go. "Is there another country?" they asked among themselves.
Now there came two beings called Alke'na ashi, Made Again, who looked like the Yei. They were sent to the East to look for the dead body. They returned and said that they had not seen it. They were sent to the South and they brought back the same report. They were sent to the West and the North without success. They were asked to look into the Yellow World where they had come from. As they were about to start they felt the flesh around their knees pinched; but they went on. They had a strange feeling of sound, like a rale, in their throats. They felt rather than heard this sound, but they went on. Then there was a sensation in their noses, like an odor, but they went on to the place of emergence, and they looked down. Way below them there was someone combing his hair. He looked up and gave a little whistle, and they both experienced a strange feeling.
When the Alke'na ashi returned from the lower world they said that they had seen the spirit of the one who had died. They told just what they had felt and seen.
They warned the others saying that they must not try to return to the Country of the Past for it was not well to experience such sensations nor to see such things; and if in the future someone were to hear a whistle when no one was about that whistle came from an evil source, and a prayer should be said at once. If anyone should be so unfortunate as to see their double, or the form of a near relative in a vision, it would be a sign that dangerous things were about to befall them. Should this happen a chant must be held and prayers said in order to ward off the trouble.
The First People thought a great deal about this person's dying.
It had been First Man's and First Woman's plan to have everyone live forever. There was to have been no death. They could not understand this thing; and they were not satisfied.
First Man and First Woman got a piece of hard, black wood. They made a smooth pole of it, and pointed it, as an arrow is pointed.

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Its length was the distance from a tall man's fingertip to his heart. After this pole was fashioned they dressed it; and they carried it on their shoulders to a lake. It was their plan to cast it into the water, and if the pole floated to the shore there would be no death; but if it sank down into the water, then death would remain. Now just as they raised it to cast it into the water the Coyote came to them. They saw that he carried a big stone ax. As they cast the pole into the water he threw the stone ax, saying: "Unless this stone ax returns to the surface there will be death." Now the stone ax remained in the lake, but the pole which First Man and First Woman had shaped and dressed returned to the shore. So it was decided that, although there would be death among the people of the earth, sometimes the very ill would recover because the log had floated back to the shore.