Preposterous. Elves do not poop. They are so in tune with nature and the magic of the world that their bodies are extremely efficient at deriving all possible sustenance from what they eat so that they do not produce any bodily waste. That’s one of the reasons why they are so long-lived. In fact, elves believe that the fact that humans do produce such (copious amounts of) bodily waste is one of their reasons why they are so short-lived. They are literally pissing and crapping perfectly good nutrients away and turning into, well, crap. The first elves who encountered humans gave them the benefit of the doubt and thought that they were more like rabbits in this regard, but they were soon disabused of that notion. There was even an elven archmage and druid who, in a misguided attempt at humanitarianism, tried to “correct” this obvious deficiency of the human gastrointestinal system in order to prolong their lives. It didn’t end well. The movie “The Human Centipede” is based on this embarrassment of elven science, which is the most you’ll ever learn about this particular incident from anyone as the elves struck all record of it from their histories save for an entry in their list of “Things Never To Do Again”.