In the novel White Fang when do you see the theme of " Dog nature vs. Wolf nature" why is this theme important and what quote would best represent the theme and what does that quote mean?

This is the only quote I found that I believe takes on both sides of the theme;

"He was realizing his own meaning in the world; he was doing that for which he was made-killing meat and battling to kill it. He was justifying his existence, than which life can do no greater; for life achieves its summit when it does to the uttermost that which it was equipped to do (II.4)."

For White Fang to have understood that he had to cling to the wolf and leave any sense of domesticity behind was a life changing moment. Survival was of the utmost importance............. at different time, he had to be different things in order to survive, but I think the hardest of these would have been to return to the wolf after experiencing domesticity.