Remember that dang turtle in Chapter Three? You know the one. The turtle who kept trying to cross the road, who was dead set on going in a specific direction, but who was nearly run over by cars, and who was picked up and stuffed into Tom Joad's coat? We know what you were thinking when you read this chapter: "Um, Mr. Steinbeck? We like turtles and all, but what the HEY is so important about this turtle? Why do you keep writing about him?"
Well, this stubborn and determined turtle, who almost becomes a Joad pet, reminds us of the stubborn and determined ways of the Joad family and other migrant worker families who persevere even after being kicked off of their farms, cheated by used car salesmen and merchants, and set back by sickness and loss. The turtle accepts the challenges that come his way, but he never forgets where he is going.
Another animal reference is the cat that Tom Joad sees. He recognizes it as an old family cat hanging around his abandoned family farm. Just like the migrant workers, the cat has been turned out of its home. The cat now lives in the wild and must survive on mice and other creatures. It has been transformed from a domestic pet to a wild animal.
We also want to mention the way in which the Joad's dog dies. Sure, the Joads didn't really have a lovey-dovey relationship with this dog, and didn't even have a name for him, but he is the family dog nonetheless. This dog is run over by a speeding, westbound car, and his body is so mangled as a result that his guts lie strewn on the road. We get the feeling that his death foreshadows the gruesome circumstances that lie ahead for the Joads, and of the tough, unrelenting life that awaits them. Times are hard, and people are so desperate and angry that they will not hesitate to run over a dog, or to ruin a family's life.
The cars on the road are also like animals, "limping along 66 like wounded things, panting and struggling" (12.44). We watch humans kill animals without a second thought (remember the Joad pig fest?), and we begin to see similarities between the ways humans and their furry friends behave during desperate times.