What’s significant about the rat ?

Bigger is afraid of the rat.... it invades his living space and in response., he kills it. This is significant because over the course of the novel, the reader comes to see that the rat is, in fact, a symbol of Bigger himself. In the same way the rat makes its way into Bigger's home, Bigger finds himself employed by the Daltons, who live in a completely different world. In addition, when the rat finds its way into Bigger's home, it is immediately set upon and killed. Bigger, in turn, is confronted by racism..... foreshadowing his own death.