A powerful dog, half St. Bernard and half sheepdog, who is stolen from a California estate and sold as a sled dog in the Arctic. Buck gradually evolves from a pampered pet into a fierce, masterful animal, able to hold his own in the cruel, kill-or-be-killed world of the North. Though he loves his final master, John Thornton, he feels the wild calling him away from civilization and longs to reconnect with the primitive roots of his species.

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John Thornton

Buck’s final master, a gold hunter experienced in the ways of the Klondike. Thornton saves Buck from death at the hands of Hal, and Buck rewards Thornton with fierce loyalty. Thornton’s relationship to Buck is the ideal man-dog relationship: each guards the other’s back and is completely devoted to the other. The strength of their bond is enough to keep Buck from acting on the forces he feels are calling him into the wild.

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Buck’s archrival and the original leader of Francois’s dog team. Spitz is a fierce animal—a “devil-dog,” one man calls him—who is used to fighting with other dogs and winning. He meets his match in Buck, however, who is as strong as Spitz and possesses more cunning. Spitz is an amoral being who fights for survival with all of his might, disregarding what is right and wrong.

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A French Canadian mail driver who buys Buck and adds him to his team. Francois is an experienced man, accustomed to life in the North, and he impresses Buck with his fairness and good sense.


A French Canadian who, together with Francois, turns Buck into a sled dog for the Canadian government. Both Perrault and Francois speak in heavily accented English, which London distinguishes from the rest of the novel’s dialogue.


An American gold seeker, Hal comes to Canada with his sister, Mercedes, and her husband, Charles, in search of adventure and riches. The three buy Buck and his team and try to drive them, but their inexperience makes them terrible masters, as they run out of food during the journey and bicker among themselves. Hal and his companions are meant to represent the weakness of overcivilized men and to embody the man-dog relationship at its worst.

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Charles’s wife and Hal’s sister. Mercedes is spoiled and pampered, and her unreasonable demands slow her, Hal, and Charles on their journey and contribute to its disastrous ending. Her civilized manner, however, contrasts that of her unprepared brother and husband in that she initially feels sympathetic for the worn-out sled team. Her behavior, London suggests, demonstrates how civilized women are unsuited for life in the wild, having been spoiled and babied by the men around them.

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Hal’s brother-in-law and Mercedes’ husband. Charles shares their inexperience and folly.

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A dog on Buck’s team. Dave becomes ill on one of the team’s journeys but refuses to leave the harness, preferring to die pulling the sled. In his stubbornness at this task, Dave is an example of gritty determination.

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An older, more experienced dog on Buck’s team.


A friend of Buck’s, met on the journey to the North. Curly’s death, when she naively tries to be friendly to a husky, acts as a warning to Buck of the harshness and cruelty of his new home.

Judge Miller

Buck’s original master, the owner of a large estate in California’s Santa Clara Valley.


A gardener’s helper on Judge Miller’s estate. Manuel kidnaps Buck and sells him in order to pay off his gambling debts.