One day, the cub comes quickly out of the cave and down to the stream. Of what does he suddenly become aware?

The cub becomes aware that he is not alone.... he is in the presence of man.

Before him, sitting silently on their haunches, were five live things, the like of which he had never seen before. It was his first glimpse of mankind. But at the sight of him the five men did not spring to their feet, nor show their teeth, nor snarl. They did not move, but sat there, silent and ominous.