Symbols in The Grapes of Wrath
Blood is one of the more pervasive Grapes of Wrath symbols. It appears over and over again throughout the novel, in such examples as the death of the Joads' dog, the birth of Rose of Sharon's baby, the pig slaughter, and Tom's cutting his hand while fixing the car -- among others. There are also figurative references to blood in the ways that the soil of Oklahoma is drained of its vitality by the thirsty cotton crop, and by the ongoing drought, and in the ways that the farmers of Oklahoma are bled by the banks.
The significance of this symbol has to do with Steinbeck's rhetorical argument that the rich were bleeding the poor dry and profiting from the experience. The employers in California were similarly, in Steinbeck's view, bleeding the migrant workers dry by paying them so little (and by indebting them to the company store) that they could never escape poverty -- and could never afford to leave the company's employ.
While quieter than blood, the sun serves as one of the powerful Grapes of Wrath symbols. When there is a drought, the sun is an implacable, constant presence, and it remains with the Joads, even after they leave their foreclosed farm behind to go work in California. As they ride in their truck, they develop a sunburn, and there is no relief from it. And so not only has the sun ruined the Joads' crops, it also brings them pain as they head west.
While much of what Steinbeck has to say in The Grapes of Wrath concerns the ways in which people oppress one another, the cruelty of nature also appears in the novel, and this symbol is one of the many expressions.
Animals and Insects
The first of the Grapes of Wrath symbols from the wild is the turtle, who appears in the "intercalary" chapters early in the novel -- those that interrupt the Joad narrative with its progress. The turtle is headed somewhere, and won't change direction, even though cars menace it. Eventually, it ends up in Tom Joad's coat.
This turtle represents the persistence of the migrants, who refuse to give up even after their farms have been taken away by the banks, their money has been cheated from them by dirty car salesmen and other business owners, and their family members have sickened and died.
The Joad's dog dies in such a grotesque way that one can't help but see it as an omen for the distortion and destruction of the Joad family through the rest of the novel. Not only will many of the family members simply pass away, but those who do remain will have their lives twisted irrevocably.
The grasshoppers that block out the sun, in the novel's reference, and destroy crops, bring to mind the Old Testament curse called down on the Egyptians, involving the locusts. The idea here, as mentioned above, is that nature can indeed be cruel, especially if there is no human intervention to help the dispossessed.