^w^ Many sharks swallow their food in large, unchewed pieces and leave the entire job of processing to the stomach and intestines.
^w^ Sharks don't eat often and process food very slowly. In some sharks, it takes more than three days to digest a meal.
^w^ The sharks digestive system, called the `spiral valve`, looks like a spiral staircase tightly wound into a small tube, and provides a lot of surface in very little space.
^w^ When a shark swallows something indigestible the shark can turn its stomach inside out and get rid of the contents. A shark can unroll and empty the spiral valve in much the same way.
