There are two people in the story who are the kindest to Buck. At the novel's beginning, Buck's master is gentle, kindly Judge Miller, who symbolizes the civilized world, where people live according to law and custom. After being stolen from the Miller home and suffering many abuses and hardships, Buck finally encounters John Thornton, an adventurer who also symbolizes the survival of the fittest. He shows great compassion for the dogs that work hard pulling sleds, but none for the stupidity of the three people who venture into the harsh north country with neither the necessary knowledge nor the patience to learn about the wilderness. Thornton shows Buck loyalty and admiration, which he demonstrates when Thornton is offered a thousand dollars for Buck but he refuses.

The main character is Buck, and the central theme of the novel is his evolution from a life of domesticated ease to survival in the harsh northern wild. For London, Buck represents the idea that within every human is a more primitive version of the individual that can emerge in life-threatening situations or periods of extreme stress. Buck symbolizes the Darwinian idea of survival of the fittestonly the strongest and most adaptable will survive. This symbolism is carried further by Buck's exhibiting many human traits, including loyalty, love, and revenge. From his first cruel master, the Man in the Red Sweater, he learns that a single dog is no match for a human with a club. It is a harsh and painful lesson, but it serves him well. Buck knows instinctively that the inept adventurers, Charles, Mercedes, and Hal, will meet with disaster: The wilderness will not forgive their mistakes. It is for this reason, among others, that he refuses to go with them after they reach Thornton's camp just before the trio drowns under the ice.

Buck fights his way to the top of the pack, becoming the leader of the sled-dog team after he conquers Spitz in a brutal fight. Despite his aggressively individualistic tendencies, Buck also realizes that the sled team can only function if all of the dogs work together.

Newcomers to the North Country are Charles, Mercedes, and Hal, who represent those least adapted for survival. They die because they fail to understand how to live in the wild. Unprepared to deal with the harsh conditions of the North Country, they deal with it by fighting with each other and lashing out at the animals. For instance, before they stumble upon Thornton's camp, they discover that they do not have enough food for the dogs. Lack of food causes the animals to grow weak, but instead of recognizing this and trying to help it, Mercedes insists on riding in the sled, increasing the dogs' burden. In the end, their incompetence leads them to travel over ice too thin to support their weight, causing them to drown in the freezing waters.

On the trail, dogs were fed dried salmon, each dog receiving two pounds of fish each day. They were fed once a day, and always at night. This was done to encourage them to make better time on the trail, as dogs tended to become lazy after feeding.

Various breeds of dog were used for freighting in the Yukon. The most sought-after were the native breeds the husky, the malamute, and the Siwash, or Indian dog. Though they were often bad-tempered, giving rise to vicious dog fight

Some common words found in the essay are:
Call Wild, St Bernard, Buck Yukon, Ghost Dog, Siwash Indian, Hal Buck, Black Burton, North Country, Charles Mercedes, Valley California, call wild, charles mercedes, gold rush, native dogs, north country, buck learns, hal charles mercedes, rush yukon, learns survive, hal charles, law club fang, harsh conditions, joins wolf pack, buck learns survive, gold rush yukon,
Approximate Word count = 2225
Approximate Pages = 9 (250 words per page double spaced)