In John Steinbeck's novel The Grapes of Wrath, the Joad family and the changing world in which they live is described from a naturalistic point of view. Steinbeck characterizes the Joads and their fellow migrants as simple, instinct bound creatures who are on an endless search for paradise. The migrants and the powers which force them to make their journey nature and society are frequently represented by animals. The Joads, when they initially leave home, are a group of simpleminded, animal like people who barely understand or even realize their troubles, but as the story progresses, they begin to grow and adapt to their new settings. They evolve from a small, petty group of creatures with no societal consciousness into a single member of a much larger family society.
Steinbeck strongly portrays the Joads and other displaced "Okies" as being animalistic. They often talk about their predicament in simplistic terms that suggest that they are initially not conscious of the circumstances that force them to leave Oklahoma. Muley Graves, for instance, tells Tom Joad and Jim Casy that the rest of the Joads, whose house has been destroyed by a tractor, are "piled in John's house like gophers in a winter burrow." This presents the image of a family of animals that have clustered together, hoping to fend off a predator with their greater numbers. They see the societal problems around them in terms of a predator as well; on one occasion, Casy asks a man at a service station, "You ever seen one a them Gila monsters take hold, mister? (Chop him in two) an' his head hangs on. An' while he's layin' there, poison is drippin' into the hole he's made." This refers to the shocking, unbreakable grip of the socioeconomic forces at work above them. A particularly important element that represents the migrants on a naturalistic level is the turtle. Introduced in the beginning, the turtle trudges along wearily but steadily on a relentless search for a better place to life....