How does Buck signal his transformation at the end of the novel?

The transformation of Buck at the end of the novel is symbolized by his decision to join a wolf pack and fully embrace his wild nature. Throughout the story, Buck evolves from a domesticated pet into a creature attuned to the primal instincts of the wild. This joining signifies the culmination of his journey—having shed the constraints of civilization and civilized behavior, he accepts his true identity as a wild animal.

This choice highlights Buck's complete adaptation to life in the wilderness and reflects the overarching theme of returning to one's primal roots. His acceptance and integration into the wolf pack illustrate his newfound freedom and connection to nature, contrasting markedly with his life under human control. This final act not only emphasizes Buck's transformation but also embodies the essence of the wild, which he has come to understand and embrace fully.