While both dogs are cunning and experienced fighters, Buck proves himself superior at the end of chapter three, when he kills Spitz.

In terms of similarities, both dogs are born leaders, both are immensely strong and cunning, and both are extremely physically fit. They are also both aware that it is through bravery and strength in combat that a leadership position is claimed. Both dogs use force and their superior strength to coerce the other dogs to bow to their leadership.

One of the first differences between the two that comes to mind is their background. By the time Buck gets kidnapped from his easy life in the Santa Clara Valley, Spitz is already an experienced sled dog and the leader of the pack.

Another remarkable difference is that Buck proves to be a stronger leader than Spitz. Buck quickly proves himself to be Spitz's superior, thinking sharper and acting quicker than Spitz ever did. Once Spitz is dead, and Buck is thus no longer embroiled in a power struggle, Buck proves himself to be a leader who leads by example, which is a stark contrast to Spitz, who ruled by fear and tyranny.

François raises another difference between the dogs after Spitz's death. He comments that "now we make good time" with Buck at the helm, and now that there is "no more Spitz," there is also "no more trouble."