The willingness to accept small defeats in the name of long-term goals is a notable feature of our protagonist here. Buck realizes that he must submit to man’s weapons and to his new life as a sled dog, but submitting enables him to fight and win what are ultimately larger battles. This may be the quality that most differentiates Buck from the other dogs.
Buck is differentiated from the other dogs, and especially from Spitz, by his ability to submit rather than blindly fight.
While many changes in his character contribute to his adaptation to the wild, Buck's decision to stop submitting defines his personal transition.