When buck from call of the wild, where did he go?

-Buck begins the story as a pet dog on a ranch in Cali. In his small way, he "rules over the estate," which basically means getting to chase squirrels around all day.
-Manuel steals him.He gets beaten by the man wearing the red sweater.
-He gets sold to Perrault and François.Buck adapts to snow, other dogs, and starvation.
-Buck feels "the call."
-There’s an initial fight with Spitz, then some time passes, and finally the ultimate fight occurs in which he kills Spitz.
-Buck takes over as leader.Buck almost dies at the abusive and ignorant hands of Hal, Charles, and Mercedes.
-The lucky dog is saved by Thornton and develops a love for him.
-Buck does some impressive things, like pulling obscene amounts of weight.
-Buck becomes increasingly wild and even kills a bull.
-Buck flips out when Thornton dies, and he kills several Yeehats as revenge.
-Buck becomes a thing of the wild, leading a pack of wolves.