Beside the swimming pool in which the magnificent hippopotamuses laze about their days at the Saint Louis Zoo is a simple interactive display: Turn a crank and the tail of a cartoon hippo spins, scattering its poop among the small fish swimming around it. The point is to educate zoogoers about the food chain. The smallest fish feed on the poop and are in turn eaten by bigger fish, which are in turn eaten by even bigger fish, and so on until the biggest fish is caught by humans and becomes dinner. Yes, the food chain is a handy metaphor for how the elite few make their millions on the backs of the working class, but that isn't quite the metaphor we mean. No: Take a closer look at the littlest fish scattered about the hippo's scat. They are smiling. And why not? If you eat shit your entire life, you might as well wear a shit-eating grin.