Certainly, the naturalism of Steinbeck's writing is evinced in the characterization of Lennie Small of Of Mice and Men who, in the exposition of this novella possesses a gait like that of a bear who drags his feet and has hands described as "paws." After their long trek from the bus that let them off a few miles south of Soledad, George and Lennie come to a clearing where Lennie dips his entire head under the water in order to drink and refresh himself. That there is a Darwinian determinism to the character of Lennie is evident as this opening scene is identical to the final scene, and George's early description to Slim of the incident in Weed with the girl in the red dress is similar to the fateful one of Curley's wife, who also is associated with red.
Of diminished mental capacities, Lennie depends upon George for approval. When George scolds Lennie in Chapter One, Lennie is hurt and tells George that he will just go away and live "off in the hills or in a cave" or something, but he is terrorized to think of being alone. Always, he seeks advice from George regarding his conduct and speech. Fearful that he will anger George, Lennie tries to behave, saying repeatedly, "I don't want no trouble" after Curley enters the bunkhouse, for instance. But, when Curley attacks him, Lennie only hurts Curley after George tells him, "Get him, Lennie. Don't let him do it."
Childlike, Lennie is the keeper of the dream of owning a farm as he constantly asks George to "Tell about how it's gonna be"; he also has George recite about their fraternity,
"Guys like us, that work on ranches, are the loneliest guys in the world. They got no family. They don't belong no place.....With us it ain't like that. We got a future. We got somebody to talk to that gives a damn about us....."
Lennie's relationship with George is a symbiotic one. Critic Roger Moore explores the relationship of George and Lennie in his essay "Of Mice and Men: George and Lennie." Moore writes,
Lennie wears the same clothes as George and even imitates his gestures. The extent of Lennie's psychological integration with the George is acutely apparent in the novel's concluding chapter when the giant rabbit of his stricken conscience mouths George's words in Lennie's own voice.
When George has to shoot Lennie in the final chapter, the determinism of this scene is apparent in its repetition of the setting of Chapter One. With Lennie's death is the death of the fraternity of men and the dream, for as George remarks,
"I think I knowed we'd never do her. He usta like to hear about it so much I got to thinking maybe we would."
Lennie is pursued as though he is a hunted animal after Curley's wife is discovered by the others. But, it is too late as George has put the bear-like Lennie out of his future misery after he returns to the stream described in Chapter One where the "best laid plans of mice and men go awry."