Nature imagery

Steinbeck uses animal imagery as a metaphor for the greed that is enveloping Kino:

But Kino had grown tight and hard. He felt the creeping of fate, the circling of wolves, the hover of vultures. He felt the evil coagulating about him, and he was helpless to protect himself. He heard in his ears the evil music. And on the black velvet the great pearl glistened, so that the dealer could not keep his eyes from it.