Where's the Banana

T loves "Goodnight Gorilla." We've been reading it near daily for months and I almost always ask "where's the banana." He's very good at finding and pointing to the banana on any page, but recently he started pointing to his tummy and saying "tummy" instead of pointing to the banana in the book. He also used to say "RAWER" when I asked "what does the lion say?" Now he says "op'n it." Apparently the lion has evolved from making standard animal sounds to asking the gorilla to open the cage door.