In Jack London's novel The Call of the Wild, neither beast nor man is truly characterized as civilized. However, ironically, the lead dog Buck, who is also the protagonist of the story, is far more civilized than many of the human beings in the story.
Throughout the story, the humans the dogs come into contact with are extremely cruel, selling them for profit and mistreating them. Only the men named Perrault and Francois, two French-Canadians who purchase Buck once in Alaska to make runs delivering mail, prove to be decent men. As Buck phrases it, Perrault and Francois treat the dogs well, and though Buck "developed no affection for them, he none the less grew honestly to respect them" (p. 37).
In contrast to most of the cruel, uncivilized men Buck comes in contact with, Buck shows a sense of bravery and devotion that only the civilized can show. Buck became such a strong, devoted leader of the dog team that his name rose in fame. Be that as it may, Buck too shows his savage, or instinctive, side. One thing he notes is the amount of savagery present on board the ship sailing to Alaska in the beginning of the story. Both men and dogs on the ship are extremely violent. The dogs even acted like wolves, senselessly killing one of their own kind. On the boat, Buck makes an enemy of Spitz, a dog he is soon teamed up with once in Alaska, and though Buck is horrified by the scene of senseless killing on the boat, Buck's own instinctive side takes over when he later murders Spitz to take over as lead dog.
Hence, London uses the book to show that neither man nor beast are truly civilized. Instead, men can be just as savage as beasts, and beasts can be even more rational than men while still being subjected to their own animal instincts.