Considered Jack London's greatest novel, The Call of the Wild has as its main character a St. Bernard/Scotch shephard-mix dog named Buck. After Buck is stolen from his comfortable life as the pet of Judge Miller, he undergoes many challenges with different owners in the Klondike until he finally answers "the call of the wild." There are several dogs who act as characters as well as a few people.
- Manuel - A gardener for Judge Miller in Santa Clara, California, Manuel gets into debt from his gambling. So, in order to pay his debts, he steals Buck and sells him in the black market.
- The man in the red sweater - A brutal dog trainer who uses a club
- Francois - A French-Canadian dog driver, he trains dogs for the sled. With Perrault, he works as a courier.He cries when new orders come in, parting him from Buck.
- Perrault - Partner with Francois, a courier for the Canadian Government, Perrault is gladdened by the purchase of Buck because he wants the best dogs so that they can make good time. "Nothing daunted him." He takes risks and withstands terrible weather conditions.
- A Scot half-breed - After orders come for Perrault and Francois, he takes charge of Buck and the other dogs driving them to Dawson.
- Hal - After the dogs leave Dawson, they arrive dead-tired in Skagway; nevertheless, the gold-hungry Hal buys them, sled, harnesses and all. Miles into their trip, Buck refuses to cross the ice and Hal beats him.
- Charles- The brother-in-law of Hal and the brother of Mercedes. He is unprepared for the Alaskan wilderness.
- Mercedes - sister to Charles, she is too soft for the wilderness. With too much baggage and her refusal to walk, she overburdens the dogs. She and Charles and Hal all go to their deaths after the ice breaks as they attempt a precarious river trailafter being told to lay over because of the rotten ice. Hal tells Thorton they will continue, anyway; however, "The bottom had dropped out of the trail."
- John Thorton - An animal lover, Thorton is appalled at the behavior of the inexperienced Charles, Hal, and Mercedes, but he knows "It was idle...to get between a fool and his folly." When Hal beats Buck, Thorton, in a rage, threatens Hal if he touches Buck. Knocking Hal's knife from his hand, he cuts the traces for Buck, releasing the dog. Buck, then, becomes his loyal friend, saving him when his boat overturns, and trying to save him from an Indian attack.
- Buck - The protagonist of the novel, Buck undergoes many changes, but he adapts to his new life. When John Thorton saves Buck's life, the dog becomes completely devoted to him until the man's death. Then he avenges Thorton's death, until finally answered the "call of the wild."
- Dave - The wheel-dog on the drive, an "experienced wheeler," Dave is brave and dauntless. Even when he is finished, Dave tries to drive the team, anyway. But, he finally lies crying in the snow.
- Sol-leks - Sol-leks is one of the trained sled-dogs who teaches Buck "the ropes" as Buck is placed between him and Sol-leks.
- Spitz - A rival of Buck, he shows his teeth at every opportunity, and tries to kill Buck after stealing his "nest." But, after several confrontations, Buck remains the Alpha male.
- Pike - "the malingerer" who stays in his nest, not wanting to work; his actions cause Spitz to become angry and fight with Buck.
- Billee - Another of the sled-dogs, Billee is badly hurt in the melee with the wild huskies that steal the men's food and attack the dogs.
- Dolly - a dog who goes mad at the Pelly one morning. Francois kills her as she chases Buck back into camp.