With the wolf-dog as a frame of reference, Jack London portrays "the man" as unsuited for the arctic climate in which he ventures forth without "imagination."
Fifty degrees below zero was to him just precisely fifty degrees below zero. That there should be anything more to it than that was a thought that never entered his head.
Because he does not have the innate survival skills or understanding of the cold of the animal, nor the adaptation to his environment, the man finds himself endangered, especially because he has not gone out with a partner, who could come to his aid when his hands are too frozen to strike the match to reignite a fire which will provide him the warmth necessary for his survival.
This neophyte to the arctic has developed no instincts; consequently, he has only his pride to guide him as he does not heed the advice of the old-timer at Sulfur Creek to not go, or at least take with him a partner. For, despite all his efforts to make his hands and fingers move to light the match for the second fire that can save his life after the first he builds to thaw out his foot frozen from having gone into an ice water pool has been extinguished by snow, he cannot will these hands to work for him. Thus, with detachment and objectivity, Jack London presents a human being subjected to natural forces beyond his control. As the man dies, the dog smells the scent of death and howls.
Then it turned and trotted up the trail in the direction of the camp it knew, where there were the other food providers and fire providers.
Never in the dog's experience has it seen a man sit in the snow and not build a fire, so it knows to return to the camp. This man has lost his atavistic instincts and tried to survive upon his intelligence and failed.