In Jack London's novel The Call of the Wild, Buck starts out as a domesticated dog of a gentleman living the good life. Then he is taken out of his easy surroundings and thrust into a life with hard men as his masters. Now, Buck is a smart dog, and observes what he needs to know to survive.
Dogs and wolves share the deep seated love of the wilderness and the life of the wild with no man to interfere. Wolves and dogs both are pack animals in that the survival of their group is more important than the survival of one. The laws of nature prevail with the strong surviving and the weak dying. They differ in that dogs will follow their master offering their loyalty and love to the human who loves them. At the end when Buck trots off to the woods and the wild, we truly know that Buck is no longer a dog but has returned to the wild because there now is no human who holds him to the life of a dog.