Epigraphs are like little appetizers to the great entrée of a story. They illuminate important aspects of the story, and they get us headed in the right direction.
It is never too late to be
what you might have been.
—George Eliot
What's up with the epigraph?
In a book that opens to a pretty depressing scene—hey there, wild animals in terrible captivity—the epigraph warns readers not to give up hope. And indeed, though it takes Ivan a while to come to it, he revitalizes himself, rising to rescue Ruby from a terrible fate and, in the process, reconnecting with his own powerful ways. His connection to the wild may have slowly been drained from him after years living in the mall, but Ivan eventually finds his way back to his gorilla ways, a development which is exemplified by his move to the zoo.
Ivan may have lost touch with how to be a wild gorilla and the power that comes with being such a creature, but though decades have passed, he manages to tap back into these parts of himself and influence not only Ruby's future, but his own, too.