Buck stood and looked on, the successful champion, the dominant primordial beast who had made his kill and found it good.
Buck turns to his primitive instincts more and more as he struggles to survive in the wild North. He avoids fights, but Spitz becomes a dangerous rival, showing his teeth whenever possible. One night, Buck settles down under the shelter of a rock, but when he goes to get his food, he finds the space occupied by Spitz. He springs upon Spitz, surprising him, and the two circle each other, preparing to fight, while Francois eggs Buck on. Just then, they hear Perrault shouting and see almost a hundred starving huskies charging into the camp. The wild dogs are so thin that their bones seem to be coming out of their skin, and they are mad with hunger. Buck is attacked by three huskies at once, and his head and shoulders are slashed; even as he fights the wild dogs, Spitz continues to nip at him. Eventually, outnumbered, the sled dogs run out onto the frozen lake and regroup in the woods. They are all badly hurt. In the morning, they make their way back to the camp but find no food there. Surveying the damage, Francois worries that the wild dogs were mad and that their bites may have infected the sled dogs, but Perrault doubts it.
Four hundred miles of trail remain, and the team reaches the most difficult stretch—frozen lakes and rivers where the surface is partially melted. At times they take great risks, and many of the dogs break through the ice and almost freeze to death or drown. Dolly, one of the dogs, goes mad one morning and begins chasing Buck. Francois kills the mad dog with an ax, and Buck is left exhausted from running. Spitz springs on him, but Francois attacks him with his whip. From then on, Buck and Spitz remain rivals engaged in an undeclared war. A fight to the death seems inevitable. Even Francois and Perrault realize it, with Francois betting on Buck and Perrault on Spitz. Before they reach Dawson, Buck threatens Spitz’s leadership by siding with the weaker dogs when Spitz tries to bring them into line. But no opportunity for a fight presents itself, and they arrive in the town with the outcome of the struggle still uncertain.
After a brief stopover in Dawson, the team pushes on toward Skaguay, with Buck’s insurrection against Spitz growing every day. One night the team spots a rabbit, and fifty dogs from the Northwest Police camp join in the hunt. Buck leads the pack, but Spitz, unbeknownst to Buck, leaves the pack and cuts across a narrow piece of land. Buck thinks that he will catch the rabbit but then sees Spitz cut him off. As Spitz’s jaw clamps down on the rabbit’s back, Buck drives into Spitz, and the two roll over and over in the snow. Buck realizes that they are locked in a battle to the death. Spitz is a practiced fighter and fends off Buck’s attacks patiently. After a few minutes, Buck is dripping with blood, while Spitz is virtually untouched. Spitz begins to rush him, but Buck tricks his rival, faking a rush against the other dog’s shoulder and then diving for the leg, instead, and breaking it. Crippled, Spitz soon goes down and, as the other dogs gather to watch, Buck finishes him off.
This chapter emphasizes the external dangers of the wild. Life within the world of gold rush towns and sled teams can be dangerous enough, as Curly’s death and Buck’s rivalry with Spitz demonstrate. But worse threats lurk beyond the confines of camps and mail routes—wild dogs, for one thing, and madness, for another. Hunger also threatens, a terrible enemy that has transformed the wild dogs into weird, skeletal, half-mad creatures. At this point, hunger is not a direct threat to Buck, since Francois and Perrault are responsible masters. But later in the novel, when Buck is in the care of less experienced humans, it rears its head again, and the image of the starving wild dogs foreshadows Buck’s later experience with hunger.
Meanwhile, the competition between Buck and Spitz, in which each strives to be “the dominant primordial beast,” builds to a climactic resolution. In the Buck-Spitz war, we see again the way that London’s dogs resemble humans: Buck’s revolt against Spitz is first of all a matter of strength versus strength, but it is also political. Buck does not merely attack Spitz head-on; instead, he slyly undercuts Spitz’s authority among the other dogs by siding with the weaker animals in disputes. Thus, he paves the way for his own leadership even before the final confrontation arrives.
While Darwinism clearly influenced London’s writing, the Buck-Spitz conflict seems to be more suggestive of the ideas of Friedrich Nietzsche—a German philosopher of the late nineteenth century. Nietzsche argued that all of society was divided up into those who were naturally masters and those who were naturally slaves. Nietzsche further argued that life was a constant struggle either to rule or be ruled; the "will to power," as he termed it, replaced a conventional system of morality or ethics. He frequently resorted to animal metaphors, referring to the conquering rulers as “birds of prey” and “blonde beasts,” and to their victims as “sheep” and “herd animals.” In The Call of the Wild, London transposes Nietzsche’s arguments about human competition to dogs in the Klondike, casting Buck as the dominant beast whose “will to power” is unmatched. His language is almost self-consciously Nietzschean: he refers to Buck as a “masterful dog,” filled with “pride” and looking forward to a “clash for leadership” because such a desire is in his “nature.”
This chapter leaves civilized morality (“slave morality,” as Nietzsche called it) far behind. Earlier, the killing of Curly horrifies Buck, whose life in California has left him unprepared to live by a new and different set of moral principles. The demands of the wild, however, force him to reconsider his scruples to the extent that he not only fights and kills Spitz but also rejoices in doing so. The story does not criticize the new, savage Buck; instead, it applauds his victory, his conquest of Spitz, and his assumption of his destiny to rule the pack alone and defeat anyone who opposes him.