What picture does the narrator paint of the man in Buck's dream?

Buck quickly achieves mastery over the other dogs. He loves to sit in front of the fire and dream. Sometimes he dimly recalls memories from his California home. More often, he is visited by visions of an ancient life, his place with ancient humans. He sometimes thinks he sees a man, different from men today, and he remembers the rustle of beasts and the readiness for the fight.