Explain why Buck's combination of dog like and wolf like characteristics make him so formidable and unique as seen especially in chapter7

At the beginning of this chapter, Buck's existence seems almost ideal. John Thornton and his partners embrace a natural lifestyle. Like the dogs themselves they prefer to hunt for their food. Rather than being depressed by hunger, the dogs enjoy the thrill of feasting some days and fasting on others. For Buck, it is almost like being with the ancient man he dreams of, for the dogs travel with the men, fighting for food, watching for danger, and constantly seeking the next destination. The needs of the men and the dogs are truly one.

When Buck takes to the forest, the reader might certainly wonder whether or not he will return to John Thornton. Buck is torn between his passionate dog love for his master and his unquenchable desire to "heed the call." When he meets and runs with his wolf brother, he understands for the first time what that call means. Though Buck once again chooses John Thornton, it is clear that this situation cannot continue indefinitely. The ending of The Call of the Wild is difficult to understand. It is possible that London chose this ending, because only the death of John Thornton would free Buck from his divided loyalties. Furthermore, killing the Yeehat Indians truly connects Buck to his wild past. He now understands that his dependence on human companionship is false. Dogs do not need humans to survive, for dogs are stronger than humans.

Buck has begun to bond with the wolves he has met and he is preparing to return to the wild. He also needs the wolflike strength to defeat the Yeehats who have killed John Thornton.