In chapter 2
Answers 1Add Yours
The first time would be when Buck is trapped in the snow in Chapter Two.
The snow walls pressed him on every side, and a great surge of fear swept through him—the fear of the wild thing for the trap. It was a token that he was harking back through his own life to the lives of his forebears; for he was a civilized dog, an unduly civilized dog, and of his own experience knew no trap and so could not of himself fear it.
Call of the Wild