Buck has an external conflict between the Yeehats, the tribe of Indians massacring his final master Thornton’s group, and himself. This is shown when “he hurl[s] himself upon them in a frenzy to destroy” (London 88) after finding Nig, a half bloodhound and half deerhound of Thornton, and Hans, his respected master’s companion, dead on the way back to the camp. The conflict reaches its climax when Buck follows the scent to the pool and ascertains Thornton’s death which “[leaves] a great void in him” (London 89). Undoubtedly, his “wild” and uncontrollable rampage derives from his greatest love “that [is] feverish and burning, that [is] adoration, that [is] madness” for his “ideal master” who not only saves his life but also “[sees] to the welfare of his dogs as if they were his own children” (London 64). Moreover, Buck’s first fight against mankind would be somehow a manifestation of his primitive instinct inherited from his ancestors and his true integration into the wild, also.
Buck’s conflict is resolved when he “pause[s] to contemplate the carcasses of the Yeehats, “forget[s] the pain of it” and realizes that men and dogs are “no match at all” (London 89). Previously, Buck feels the call of the wild; however, the only thing that prevents him from going away, that keeps him in the world of men, is his love for John Thornton. When the Yeehats kill Thornton, “the last tie is broken” (London 90), which results in the fact that he becomes “ready to obey”, feels free to follow the call of the wild past as well as his wild brother and completely embraces his wild nature.