In the book "To Build a Fire," how do the dog's reactions differ from those of the man? How come the author includes the dog's reaction?Thanks soo...

Jack London in, "To Build a Fire," does contrast the dog to the man.  As a naturalist, London sees humans as biological creatures, the same as any other creatures.  In fact, humans, when pitted against natural forces, are inferior creatures.

The dog is built to withstand the cold and ice, etc.  It does not need a fire to survive.  The man does.  The only danger the dog faces is from the man when he tries to catch and kill the dog in order to warm himself inside of the dog's warm carcass.  But even here, the dog's superior instincts make it suspect something and move out of reach.

The dog is loyal to the man, and waits as long as it can once the man freezes to death.  But it doesn't need the man.  It eventually trots away on to the next camp, where food and shelter and warmth await.