what is indicated by buck's change in eating habits ?

  Every night in camp, Buck is exhausted. He is bigger than the other dogs, and though he receives a larger ration, he never feels satisfied. Once a dainty eater, he has lost all fastidiousness after he being robbed for eating slowly. He duplicates the actions of Pike, a new dog, by stealing a whole chunk of bacon. He is not caught, and another, weaker dog is punished in his place. Buck's theft marks him as "fit to survive" in the Northland environment. Property and personal feelings can no longer be respected. He does things because they are necessary. He acts not on reason but on instinct.