On Buck's first day on the Dyea beach he sees that he has been flung from civilization into confusion and chaos. He must always be working and alert among the "savages" who know only the law of "club and fang." Attack is a constant threat. The good-natured Curly is killed simply for trying to make friendly advances towards a husky dog only half her size. The dog takes her down with efficient, quick technique. Once it is certain that Curly will not rise again, the rest of the dogs in the camp attack and kill her. Spitz, the lead dog of Buck's team, laughs. Buck hates him bitterly. He has learned that fair play does not exist, and he resolves that he will never go down.
The first time he is harnessed to the sled, his dignity is hurt but he is "too wise to rebel." Dave, an experienced wheeler, nips at Buck whenever he is making mistakes. Spitz growls at him warningly from his front post. Buck learns quickly from these two dogs, and Francois is pleased. Two more huskies, Billie and Joe, are added to the team. They are brothers, but very different. Buck receives them as comrades. Dave ignores them, while Spitz attempts to dominate them both to establish his position as lead dog. Billie immediately submits, but Joe refuses to back down, and Spits is forced to leave off. Soon another husky, Sol-leks, arrives. Like Dave, he is noncommittal and expects nothing from anyone; Buck soon discovers the only thing that will move Sol-leks. Buck accidentally approached him from his blind side, and he is given a vicious cut in return. He learns quickly not to repeat the mistake.
When Buck tries to sleep that night, he is unable to find warmth. After wandering around the camp, he decides to see how the team is making out. He comes across Billie buried in the snow, proceeds to make his own hole and fall asleep instantly. When he awakes, he instinctively forces his way out of the snow that has gathered over and around him. Without realizing it, he has begun to draw on the ancestral knowledge that is his birthright. Perrault and Francois are very glad to have Buck. When the dogs are harnessed, Buck marvels at the change in Dave and Sol-leks. They are no longer passive, but excited and ready to work. More dogs are added, and they all lose the look of unconcern as soon as they sled is moving. Buck is still learning, but soon the whip snaps less frequently.
The journey grows more difficult as the dogs have to break their own trail. Every night in camp, Buck is exhausted. He is bigger than the other dogs, and though he receives a larger ration, he never feels satisfied. Once a dainty eater, he has lost all fastidiousness after he being robbed for eating slowly. He duplicates the actions of Pike, a new dog, by stealing a whole chunk of bacon. He is not caught, and another, weaker dog is punished in his place. Buck's theft marks him as "fit to survive" in the Northland environment. Property and personal feelings can no longer be respected. He does things because they are necessary. He acts not on reason but on instinct. Buck speedily develops more heightened senses, hardened muscles, and an iron stomach. He becomes the son of his ancestors, and when he howls at the moon he repeats the same ancient song they sung before him. All of this comes about, because a gardener's assistant did not earn enough to support his family and his gambling habit.
The link between man and beast grows stronger; the distinctions are more blurry. The roles of humans and dogs become more or less equal in this chapter. Both are heading for the same place, albeit with different intentions. Buck is now part of a team, the group of dogs who pulls the sled. He must adapt quickly to the new life. These animals work together, better than any humans, to complete their allotted tasks. Buck learns how to pull and steer through punishment inflicted by the other dogs. There is little distinction made between man and dog. Francois, Dave and Sol-lek work together to teach Buck. When Dave nips Buck, Francois' "whip backs him up."
London suggests that at least some of the dogs see themselves as part of a team that includes the humans. When in the traces, "[the dogs] were alert and active, anxious that the work should go well, and fiercely irritable with whatever retarded that work." The theme of loyalty gains importance, as Buck begins to understand the satisfaction that comes from having a job and doing it well. Buck is not inspired by human goals - he does not see his rations as pay for his work. This loyalty is not the weak quality of civilization, where men must receive incentives for their allegience. This is the loyalty of savages, men and dogs bound together by their desire to survive.
London calls the rules governing this society, the "law of club and fang." Stripped of the niceties of civilization, the only rule that governs, a rule that supersedes any loyalty, is the rule of power. Curly dies because she has no understanding of her place in the power structure. She accidentally asserts a dominance she cannot back up. Leaders such as Spitz keep everyone in check. Spitz must assert his dominance over new dogs in order to establish their place in the hierarchy. Buck must see Curly's death as a lesson, for their is no time to express sympathy. Spitz's "laughter" at the terrible scene, and Buck's resultant dislike foreshadows the eventual conflict between the two dogs.
Though London vividly depicts Buck's confusion, shock and disruption, he also suggests that Buck belongs in this world. The reader finds him or herself unable to pity Buck, and instead gets pleasure out of Buck's ability to negotiate this harsh environment. His theft marks him as "fit to survive" in this place. These words clearly allude to Herbert Spencer's theory of survival of the fittest. Buck's fitness for the given conditions is proven solely by his survival. Spencer argued, and London seems to have believed, that organisms cannot learn to be "fit." Their natural and instinctual knowledge either makes them suited for the conditions of their environment, or it does not. Buck's speedy changes suggest that he was never truly fitted for his previous environment. The instincts of his more wild ancestors were always just under the surface, waiting for an opportunity to resurface.