Francois discovers that Spitz is missing and praises Buck. As the dogs are about to be harnessed, Buck trots up to the spot that Spitz occupied. Francois brings Sol-leks to the position of leader instead. Buck is furious and springs upon him. He will not let Francois harness the team. Francois retaliates by bringing in a heavy club. Bitterly snarling, but remembering his lesson at the hands of the man in the red sweater, Buck stays just out of reach. Both men try to catch him, but Buck will not relent. He wants the leadership. AFter an hour, Francois finally throws down the club, and makes a place for Buck in front.
Francois is surprised and thrilled to learn that Buck excels at leading, whipping the rest of the team into shape. Buck forces Pike to carry his share of the load, and he soundly punishes Joe for his bad behavior. At the Pink Rapids, they pick up two new dogs, Teek and Koona, and Francois is astounded by how quickly Buck breaks them. They make record time back to their starting point, and the whole team struts proudly through the town. After receiving their orders, Francois and Perrault leave the team in the care of officials, a "Scotch half-breed," and pass out of Buck's life for good.
The work is now strict and heavy, as they are pulling the mail carts back over the trail to Dawson. Life is monotonous. Feeding time is the focus of each day. Buck quickly achieves mastery over the other dogs. He loves to sit in front of the fire and dream. Sometimes he dimly recalls memories from his California home. More often, he is visited by visions of an ancient life, his place with ancient humans. He sometimes thinks he sees a man, different from men today, and he remembers the rustle of beasts and the readiness for the fight.
They reach Dawson, and rather than the usual ten days of rest, they have another load of mail only two days later. The way is much harder this time, for it has begun to snow. The men are good to the dogs, feeding them before they eat themselves. The strength of the dogs is quickly waning. Dave becomes terribly ill, but refuses to stop pulling the sled. The driver puts Sol-lek in his place, meaning to allow him to run easily behind the sled. Dave cannot stand to see another dog doing his work. He runs into the soft snow beside Sol-lek, trying to resume his usual place, yelping in pain. Finally he falls behind the sled, but at the next stopping-place he once again attempts to resume his place. Finally the driver decides it is kinder to allow Dave to pull, for he will die either way. During his final pull, he often falls and is caught in the traces of the sled. The next morning, Dave is too weak to rise. The team is driven ahead some ways, but they cannot ignore the gunshot that rings out. Buck and everyone else know what the shot means.
Though Francois recognizes and respects the hierarchical structure of the dog society, his struggle with Buck reveals a barrier between the dogs and the humans. Francois does not understand the extent to which the dogs must be allowed to master themselves. When he succumbs to Buck and lets him take the lead position in the team lineup, he learns something about the relationship of man and beast, just as when Buck learned a lesson from the man in the red sweater. In this way, they struggle as two equals, Buck trying to communicate and Francois trying to understand. This scene also suggests that the humans are slightly deluded in their confidence of ultimate control. Just as Francois and Perrault were not able to protect their dogs when the wild huskies attacked, they now cannot master Buck. The club, which is the most powerful weapon available to humans, no longer has an effect, for Buck has learned how to get his way.
In killing Spitz, Buck gained power over his pack; in forcing his position as leader, Buck gains power over his human leaders as well. He forces them to recognize their dependence on his cooperation. But he never goes to far in his rebellion. He rewards them for their trust in him by proving himself worthy of his position, and he makes his rebellion up to them by taking strong command of the other dogs.
When the two Canadian officials are gone, the team is placed in the charge of Scotch "half-breeds." When London places these phrases in Buck's mouth, he once again blurs the lines between humans and dogs. Just like Buck, men can be half-breeds. When the ownership of the dogs changes hands, Buck is able to achieve mastery rather quickly over dogs that he has just met. Buck's role in the novel is comparable to a human hero. He has come through his first major conflict and received his first reward.
One of Buck's most heroic traits is his loyalty to his fellows, and his desire to do his job well. Though Buck certainly stands out, this trait is shared by many of the dogs in The Call of the Wild. We see this illustrated most poignantly by the death of Dave. He may be weak and in horrible pain, but to remove him from the traces is to kill him before his time. Buck's dreams of ancient times suggest that a dog's passion for work may be related to it's desire for an existence similar to that ancient existence. Dave "pleads" with his eyes to remain with the team. Dave seems to understand that when his ability to work ends, his life ends, for a life without labor is no real life. Once again the reader must be reminded of Buck's earlier existence. No matter how coddled he was, London appears to be suggesting that Buck must be happier in his present life.