Symbolism, Imagery, Allegory
When you read the part about Yertle burping, did your kid collapse in a fit of hysterics? If so, good for them. Potty humor is pretty hilarious.
But after they're done laughing, take a chance to examine what that burp really means. Is this a burp that happens while the turtles are all chowing down on fish around the lily pad? Or maybe after the master chef turtle has prepared a grand old feast? Nope. It happens right when Yertle wants nothing more than to build his impossibly high stack of turtles impossibly higher, and it comes from the turtle at the very bottom of the stack.
What we're saying is, that burp isn't just any old burp. That burp symbolizes (and uh…actually is) rebellion, one that topples a brutal dictatorship. It's the burp heard round the stack.