Buck is now ready to complete his transformation from his previous civilized life to the ways of the wilderness. Whereas he was previously a devoted "friend" to John Thornton, he is now a wild creature who has learned to live by his own cunning and intelligence. Whereas earlier, he could kill any time he wanted to, he does not kill from "wantonness," cruelty, nor simply for the wild pleasure of it; he kills only when he needs food for his own preservation. Earlier, even when he was not hungry, he would practice those skills that he had already mastered — that is, he would trap various types of animals, simply for the thrill of trapping them, and then he would let them escape from him. Once, seeing a band of twenty moose, Buck chooses one exceptionally large buck, and "guided by that instinct which came from the old hunting days of the primordial world," Buck decides to stalk him, and while doing so, he notices that this particular animal has been wounded; it has a feathered arrow embedded just "forward of the flank," which causes the moose to be particularly savage. Each time that Buck lures the old moose from the rest of the herd, a younger bull moose comes to the aid of their old leader. At such moments, though, Buck merely lures him on and stalks him with the patience of the wild, a patience that is "dogged, tireless, persistent, as life itself." After a while, the younger bulls give up their protection of the old leader, realizing that it is more important to get the entire herd down to lower pasturelands. From that moment on, both night and day, Buck constantly stalks his prey, in a relentless manner, never permitting it to relax. At the end of the fourth day, Buck finally pulls the great moose down, and after enjoying the kill, he feels refreshed and renewed and decides to find John Thornton's camp.
London's purpose in having Buck kill the wolverines and his stalking and killing the moose is to let the reader know that Buck has now totally mastered the ways of the wilderness; from now on, Buck will be able to survive in the wild without any help from human beings.
