One theme illustrated in the story is the man's sense of judgment contrasted with the dog's animal instincts. Throughout the story, London hints that the dog has more knowledge of survival than the man. The judgment-versus-instinct theme is evident when the man builds the first fire. While the dog wants to stay by the fire to keep warm, the man is determined to keep moving. As the dog reluctantly follows the man across a frozen river, the dog is more cautious than the man.