The Call of the Wild
How we cite our quotes:
It was inevitable that the clash for leadership should come. Buck wanted it. He wanted it because it was his nature, because he had been gripped tight by that nameless, incomprehensible pride of the trail and trace--that pride which holds dogs in the toil to the last gasp, which lures them to die joyfully in the harness, and breaks their hearts if they are cut out of the harness. This was the pride of Dave as wheel-dog, of Sol-leks as he pulled with all his strength; the pride that laid hold of them at break of camp, transforming them from sour and sullen brutes into straining, eager, ambitious creatures; the pride that spurred them on all day and dropped them at pitch of camp at night, letting them fall back into gloomy unrest and uncontent. This was the pride that bore up Spitz and made him thrash the sled-dogs who blundered and shirked in the traces or hid away at harness-up time in the morning. Likewise it was this pride that made him fear Buck as a possible lead-dog. And this was Buck's pride, too. (3.23)
Buck’s fighting Spitz is part of his reformation. In one sense, he is also fighting against his old persona by giving in to his competitive and wild nature.
He openly threatened the other's leadership. He came between him and the shirks he should have punished. And he did it deliberately. (3.24)
As Buck adapts more and more to the North, he becomes bolder in his competitive actions.
While Perrault packed the camp outfit and loaded the sled, the dog-driver proceeded to harness the dogs. 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 a fury, driving him back and standing in his place. (4.4)
Once Spitz dies, so has died a part of Buck’s old patience and humility.