The natural world presented in Of Mice and Men mirrors the world of the ranch. Like the ranch, the natural world is a dog-eat-dog place, where animal instincts and hunger trump any sense of justice or goodness. The grove is one of the book’s few settings, and while it’s a beautiful refuge from the ranch, there are still birds eating snakes and the like. The natural world is also represented as part of the duality of relationships: Lennie loves animals, but kills them. Candy loves his dog, but can’t stand up for it; and even Crooks tends to the horses that maimed him. While the natural world is romanticized, the relationship of characters to animals is a reminder that love doesn’t mean safety, and cruelty isn’t limited to the world of the ranch: it’s a fact of life. The natural world is without rhyme or reason, and often against our hopes, things die, even if you love them, because nature is as cruel as it is beautiful.
The novella uses the natural world as a sensible contrast to the madness and overly-bureaucratic justice of the civilized world.
Lennie belongs to the natural world, and George belongs to the world of men. In this way, the novella is about man’s inextricable relationship with the natural world.