Why do monkeys throw poop?

If you give typewriters to an infinite army of monkeys and let them randomly bang away at the keys for an unlimited amount of time, those adorable banana-munchers will eventually type the complete works of Shakespeare. But soft! What stench through yonder nostrils break? 'Tis their poop, and those sons of simians might just throw it at you. Why would an army of monkeys pelt you with their poop? That's the question we will attempt to answer.

But before embarking on this journey of fecal discovery, it's important to ask: how often do monkeys — and, to be more accurate here, specifically primates of the non-human variety — actually throw poop? Not very often, according to anthropology professor Karen Strier, who explained to Live Science that "primates in the wild don't normally throw feces." Rather, that behavior is more characteristic of "captive chimpanzees." There are non-captive exceptions, however, such as the wild howler monkeys in western Belize, who will apparently chuck their odorous colon fruits right at you. But generally speaking, you won't get a face full of monkey dung or stinky chimp chocolate unless you trap them in a zoo or in front of a typewriter. 

One reason a chimp at a zoo is more likely to throw poop at you is that it has no other projectiles to throw. In its natural habitat, a chimp will throw sticks or rocks to express frustration or simply show the chimps lower on the totem pole who's boss. In a zoo, however, poop is all they have, and because captivity causes stress, a confined chimp will express their unhappiness by launching brown booty missiles. 

Interestingly, if a chimp is particularly good at hitting you with their feces, then you know you've encountered a smart chimp. Emory University's Bill Hopkins and a team studied chimps' brains in relation to their poop-throwing and found that chimps who threw poop at targets more often and more accurately also "had more highly developed left brain hemispheres, which is also, non-coincidentally, where speech processing occurs in people." In short, better poop-throwers were better communicators. So if you had a monkey smart enough to intentionally reproduce Romeo and Juliet on a typewriter instead of at random, that hairy-Einstein might be too busy burying you in excrement to worry about typing anything.