The main character of the novel, Buck is a large dog born and raised in the sunny Santa Clara Valley of California. A mix of two different breeds, Buck has a sturdy frame and weighs more than some humans:

His father, Elmo, a huge St Bernard, had been the Judge’s inseparable companion and Buck did fair to follow in the way of his father. He was not so large—he weighed only one hundred and forty pounds—for his mother, Shep, had been a Scotch shepherd dog (1).

From the first chapter, Buck is proud, viewing himself as the king of his domain. His kidnapping early in the story upends his position of power, allowing his character to be put to the test. In the proceeding chapters, life in the Arctic pushes Buck more than Santa Clara ever did. By Chapter 3, Buck senses that not only does he have the fortitude to survive in the North, but that he was meant for it: “The dominant primordial beast was strong in Buck, and under the fierce conditions of trail life it grew and grew” (12). Buck’s personal growth shows the positive spiritual and physical transformations that can happen by living cohesively with nature. By the conclusion of the story, he is stronger than ever before: