The main theme in the novel, The Call of the Wild is the concept of
"survival of the fittest." This can be seen in Buck
and how he adjusts to his new environment as well as in the men and how they
are able to adapt to the environment.
Another theme is rivalry and examples of it are when: man vs. nature, such
as weather and perils of the trail; man vs. animal, such as the attack of
the starving pack; and animal vs. animal between Buck and Spitz.
The call that Buck so often hears and finally obeys is the call
of wolves, and the song he finally sings with them is their song, the song
of the pack - a chorus of long, draws-out, unforgettable howls that can be
head for miles.
Buck shares some traits with the pack he joins because dogs
and wolves are members of the same species. Dogs and wolves will mate, and
they have fertile offspring. Thus, London's telling of young wolves with Buck's
color and markings is scientifically accurate.
The gray, or timber, wolves that Buck joins resemble large,
well-developed German shepherds. Compared to these wolves, whose heads barely
reach his shoulder, Buck is indeed gigantic.
There is, however, one extremely important difference between
Buck and the wolves (and, indeed, between Buck and most dogs). Buck's killing
people is the result of all the extraordinary circumstances that have occurred
since his kidnapping. And - despite the fictional accounts of wolves killing
and eating human beings, accounts that have been terrifying readers for centuries
- there is not a single recorded case of this ever having happened.
Three years after The Call of the Wild was published,
Jack London wrote White Fang as a companion piece to the story of Buck.