The main character in the book is Buck, a half St. Bernard, half Scotch shepherd dog. In the story, he is betrayed by someone he trusts and is thrown into a harsh world. A world where you must work or be discarded. He adapts to the harsh environment, and soon enough becomes the leader of a wolf pack. Here London makes Buck a symbol of one that reaches full potential. Instead of lying around and doing nothing, he learns to work in a way he doesn't know too well about. He learns to fight and/or steal his food, if he didn't , he would have starved to death. That is why Buck is portrayed as one who achieves full potential.
Mercedes portrays the absolute opposite to Buck. She represents all that is weak in a civilized society. She cannot live without her precious belongings like her clothes. A suitcase of clothes would have been suitable for the trip, but she cannot part with her clothes, so she brings almost all of them. She doesn't know how to walk. When Charles and Hal ask her to get off the sled and hike along, she refuses and has to be carried off and dropped. When Charles and Hal set up camp, they have to go back and pick up Mercedes, who thinks she should be carried to Dawson City. Charles and Hal shouldn't have brought her along, all she was a hindrance. Jack London creates a good description of what is weak in a civilized society.
Buck was betrayed by a friend because someone needed sled dogs to go to the Yukon to mine for gold. Sacks of gold depict the idea of capitalism and the temporary feeling of wealth. Buck would have been happy at Judge Miller's estate if it weren't for the gold rush. Charles, Hal, and Mercedes wouldn't have died if they weren't trying to go to the Yukon to look for gold. Thornton and his