More important, for the naturalist, man is controlled by basic urges, and he can do very little to determine his own destiny. Forces of environment, heredity, and biological instincts combine to control man's life. These basic and elemental urges place man in a position similar to that of animals. Consequently, according to the naturalist, man can, at any moment, resort to animal instinct or animal behavior, and thus London chose to write about animals, showing them resorting, at key times, to the primitive behavior that is in their own makeup.
A man or an animal born in one type of environment is influenced accordingly — to a point where the basic actions in his life are governed by these environmental forces. Carried to an extreme, this view of life leads to determinism — that is, the idea that man (or animal) can do nothing for himself or itself and is, therefore, at the mercy of forces outside of his own self. Consequently, White Fang and Buck are molded by their early environment and during the course of each novel, each dog has to change drastically in order to continue to function in a new and different environment.
Furthermore, man and animal are the victims of their elemental drives, which are, in turn, motivated by their environment, the biological need to survive, and by the hereditary traits of the characters. For example, when Buck is placed in the great North, his first instinct is to survive in this new and different environment. The biological need to survive influences the actions of both Buck and White Fang during the earliest parts of both novels. Likewise, the hereditary traits in Buck's makeup have lain dormant for generations, but during the course of the novel, he begins to hear the primitive "call of the wild," which arouses a deep instinctual urge in him and forces him, finally, to answer the various calls of the wild. As a result, he finally resorts to the primitive forces that have lain dormant in him. In contrast, White Fang is primitive, but because he possesses some part of the tame dog, the wolf part of his psyche is able to respond to human compassion and love, and thus he is able to finally function within a civilized society.
