Dogs are marked by loyalty and their intimate relationships with human. In the two short stories ‘To Build a Fire,’ written by Jack London, and ‘The Dark Brown Dog,’ written by Stephan Crane, both writers use ‘dog’ to portray the nature of human when they face a limit of civilization. These portrayals express naturalism clearly by applying characters’ relationship to their surroundings. To begin with, both stories show how savage-like their main characters become through the dog. In the case of ‘To Build a Fire,’ the man at first thinks of the dog as a company. However, as the man involves in a desperate situation, really dying of the cold, he thinks of dissecting the dog to use it for warmth. This type of action would have never happened if the man was set in a civilized background, but such desperate measure influence the man to take animalistic approaches. Similarly, in ‘The Dark Brown Dog,’ the dog by being reticent shows the violence of human. Not only the child, but the family as a whole beats the dog just because of their mere sudden emotions. One thing to keep in mind about this story is that the family is a part of the lower society, where there exists a lack of civilization, in terms of sophisticated minds. Comparing these two stories, I could tell both writers showed all humans have an inner potential of violence when in uncivilized conditions. Although it is true that both stories fundamentally depict naturalism in their stories, there exist many differences between the two. The most fundamental difference is that ‘To Build a Fire’ shows how a man, as time progresses, turns from an intellectual being, to a desperate savage do to the environmental influence. “The Dark Brown Dog,’ on the other hand, shows how outer influence (the violent father) affects a being (the child) to excavate such savage like action (beating to dog). Also, in the former