how do we know from the end of the story that the dog has been somewhat domesticated

We know the dog is somewhat domesticated because it leaves the man not for freedom but to find the camp where warmth and food are assured.

As the twilight drew on, its eager yearning for the fire mastered it, and with a great lifting and shifting of forefeet, it whined softly, then flattened its ears down in anticipation of being chidden by the man. But the man remained silent. Later, the dog whined loudly. And still later it crept close to the man and caught the scent of death. This made the animal bristle and back away. A little longer it delayed, howling under the stars that leaped and danced and shone brightly in the cold sky. Then it turned and trotted up the trail in the direction of the camp it knew, where were the other food-providers and fire-providers.