When at work, his masters always dictated and supervised him and his team mates. As long as they made a subtle mistake or some tried to go on, they would be heavily slashed by different masters. From that Buck learned that realizing mistakes and correcting them is much better than revenge at proper times.

During the long toil, Buck and his team members are seldom to have enough to eat and drink, but one mission they had to accomplish every day, i.e. pulling the heavy sled. That was their daily work; and to their masters, that was their only reason to exist. All in all, in order to live with some value, they had to spare no effort to help their masters to pull sled in any circumstances.

In the end, Buck was transformed to another master with little experience in traveling to the north, who always slashed them to go ahead with little rest and food. On many occasions, the dogs were almost whipped to die, “the hair hung down, limp and draggled, or matted with dried blood where Hal’s club had bruised him” (Wang, 2011: 59) and his fellows were “perambulating skeletons” (Wang, 2011: 60). At one time, the dogs staggered, like wayfarers to death, and dropped down as if they had been struck dead. This time Buck could not stand up any more. The slashing went on, fortunately, he was saved by a mercy man named Thornton while the others diminished in the melted ice.

3.3 The Great Changes of Buck
The influence of heredity and environment on Buck and the idea of the survival of the fittest in natural selection are very important in the whole plot development of the novel. It is those stimulus and rules that made final contributions to Buck’s great changes from a tame dog in human civilization to finally a super dog back to the wild, and the gradual changes of Buck, in turn, reflects and proves the important influence of heredity and environment on shaping characteristics and the temperament, i.e. the idea of American naturalism.

When Buck was first kidnapped and transferred to the icy north, he was extraordinary raged and protested. After being mercilessly beaten by a stranger with club and fang, he learned for the first time that the stronger is the king, the ruler. In facing with this kind of situation, obedience is the only way to survive but not means flattering. In the bloody and brutal fighting among dogs, Buck began to know that there was no just competition, and as long as one falls down, he would be over. From then on, Buck kept alert in every minute and ready to face up with any provocative acts in any situation. In the sled team, Buck became to handle sled with great efforts and did as much better as possible, because that was the only reason he should survive in the eye of his masters. He learned how to sleep in the snow stretching as far as eyes can see. In order to survive, he began his first stealing food from his counterparts, which in much extent symbolized his adaptation as well as the degradation of his morality which was of no use but obstacle in the merciless struggling for survival. In the wilderness of the north, mercilessness and brutality is the only way to hold a place.
 
In the continuing stimulation and oppression of the cruel and primitive environment, Buck’s inner heredities and powers were gradually waken up and revived to the reality. He began to provoke the head dog in the public and led other dogs to make trouble for the head dog, and finally, by intelligence and his own tricks, slayed Spitz in a conflict under all the eyes of the dogs. Buck became delighted and excited in the chasing of game and running about wildly. He liked the chorus of the huskies, among which he seemed to stride over the flame of cold, darkness and all sufferings, coming back to the ancient primitive times when his ancestors lived. In The Call of the Wild and  White Fang, Wang said,
   “The sunland was very dim and distant, and such memories had no power over him. Far more potent were the memories of his heredity that gave things he had never seen before a seeming familiarity; the instincts which had lapsed in later days, in him, quickened and became alive again.” (2011: 44, 45), and “Dreaming there by the Yukon bank, with lazing eyes blinking at the fire, these sounds and sights of another world would make the hair to rise along his back and stand on end across his shoulders and up his neck.” (2011: 45). 自然主义在《野性的呼唤》中的体现(7):http://www.youerw.com/yingyu/lunwen_132.html