Buck was pleased with being the lead dog, and he immediately took the leadership role even when the men didn’t want him to.
When Buck arrived, Spitz was the lead dog. Buck and Spitz did not get along, because Buck’s presence, size, and strength threatened Spitz.
Spitz, as lead-dog and acknowledged master of the team, felt his supremacy threatened by this strange Southland dog. (Ch. 3)
Buck and Sptiz fight, and Buck constantly challenges and undermines Spitz. As a result, team morale suffers from the lack of discipline. When Buck and Spitz finally fight to the death, Buck wins.
Having won the title of lead dog fair and square, Buck decides to take what’s his. The two men, Francois and Perrault, are puzzled. They have their own ideas about who should be lead dog.
Buck trotted up to the place Spitz would have occupied as leader; but François, not noticing him, brought Sol-leks to the coveted position. In his judgment, Sol-leks was the best lead-dog left. Buck sprang upon Sol-leks in afury, driving him back and standing in his place. (Ch. 4)
The men can hardly argue. Buck won’t take no for an answer. He has earned the right to be lead dog, and no one is going to take that away from him.
Despite his relative inexperience, Buck is intelligent and actually quite a good lead dog. He enforces discipline well and manages to keep the team moving forward even in tough times. This shows that although Buck may not have been born to be a sled dog, he adapted well to it.