In chapter 4, “Who Has Won to Mastership,” Buck takes over as leader of the dog pack after killing his canine rival, Spitz. Buck has to prove to Francois and Perrault that he is the best dog for the position, but eventually they relent, strap him in as lead dog, and the pack makes record time on the trail. When the team sails into Skaguay, Francois and Perrault are reassigned, and another man described as a “Scotch half-breed” takes charge of the team and runs them without adequate rest. This man is nameless, showing that men are transient in Buck’s life.
Buck enjoys the campfire at night and begins to connect to his primitive self. His memories of the Judge’s house grow dim, and he begins to see a caveman-like creature in the flames. His visions suggest Buck will heed the call of the wild. As the team toils toward Dawson, Dave gets sick and is shot by the new owner. The dogs hear only the gun shot, but know what happened to Dave.