In July of 2008, Dylan Breves, then a seventeen-year-old student from New York City, made a mundane edit to a Wikipedia entry on the coati. The coati, a member of the raccoon family, is “also known as … a Brazilian aardvark,” Breves wrote. He did not cite a source for this nickname, and with good reason: he had invented it. He and his brother had spotted several coatis while on a trip to the Iguaçu Falls, in Brazil, where they had mistaken them for actual aardvarks.

“I don’t necessarily like being wrong about things,” Breves told me. “So, sort of as a joke, I slipped in the ‘also known as the Brazilian aardvark’ and then forgot about it for awhile.”

Adding a private gag to a public Wikipedia page is the kind of minor vandalism that regularly takes place on the crowdsourced Web site. When Breves made the change, he assumed that someone would catch the lack of citation and flag his edit for removal.

Over time, though, something strange happened: the nickname caught on. About a year later, Breves searched online for the phrase “Brazilian aardvark.” Not only was his edit still on Wikipedia, but his search brought up hundreds of other Web sites about coatis. References to the so-called “Brazilian aardvark” have since appeared in the Independent, the Daily Mail, and even in a book published by the University of Chicago. Breves’s role in all this seems clear: a Google search for “Brazilian aardvark” will return no mentions before Breves made the edit, in July, 2008. The claim that the coati is known as a Brazilian aardvark still remains on its Wikipedia entry, only now it cites a 2010 article in the Telegraph as evidence.

This kind of feedback loop—wherein an error that appears on Wikipedia then trickles to sources that Wikipedia considers authoritative, which are in turn used as evidence for the original falsehood—is a documented phenomenon. There’s even a Wikipedia article describing it. Some of the most well-known examples involve Wikipedia entries for famous people, such as when users edited the article on the British actor Sacha Baron Cohen to say he had worked at Goldman Sachs. When a Wikipedia editor tried to remove the apocryphal detail, it took some convincing. Because it had since appeared in several articles on Cohen in the British press, the burden was on Wikipedians to disprove the myth.

“As a long-time Wikipedia editor, it frustrates me when journalists don’t fact check Wikipedia and end up reproducing errors, because Wikipedia can only work the way it does if we have reliable sources to cite,” Stuart Geiger, a Ph.D. student at the University of California, Berkeley, School of Information wrote in an e-mail. When theoretically trustworthy sources err, absurd moments can result. Geiger, who has researched the dissemination of information on Wikipedia, points to the case of the Wikipedia founder Jimmy Wales’s birthday. Until recently, Encyclopedia Britannica said that it was August 7th, citing Wales’s marriage certificate. Wales says that his marriage certificate contains an error, and that his actual birthday is August 8th. But Wikipedia and several other mainstream sources have followed Encyclopedia Britannica’s lead and listed his birthday as August 7th. Though Wales has told journalists this story, Wikipedia’s rules value a multitude of independent sources over the word of an article’s subject. And so, the founder of Wikipedia could not get the Web site to reflect what is—according to Wales, at least—his actual birthday. (“Jimmy could be making this all up to make a point about Wikipedia, after all,” Geiger said.)

This gets at an unsettling phenomenon that Stephen Colbert once dubbed Wikiality: the idea that “any user can change any entry, and if enough users agree with them it becomes true.” No matter that Jimmy Wales says he came into this world on August 8th. The consensus says he is wrong. Colbert played with this idea by declaring that Warren Harding was a “secret Negro President.” As proof, he cited an altered version of Harding’s Wikipedia entry. (Colbert failed, in this case, to create enough of a consensus for the change to remain on Wikipedia.) Wikipedia is an experiment in crowdsourcing as much human knowledge as possible, and the logical outcome of that process is that the wisdom of the crowd often rules—as insensible as the crowd can be.

Jimmy Wales’s battle for his birthday and the mischievous edits of Stephen Colbert are amusing, but probably harmless. They have been aired for the public to see. And, in recent years, Wikipedia has made it more difficult to insert unsubstantiated facts into entries. The example of the coati’s new nickname is more insidious, though, because it points to the longstanding existence of errors so minor, obscure, or inconsequential that no one notices and, eventually, they adopt the veneer of truth. Just how many dull facts in this world originated because someone birthed them on Wikipedia? Disproving the idea that coatis are known as “Brazilian aardvarks” might be impossible at this point, not because Wikipedia’s rules make it difficult to cite “a lack of references to ‘Brazilian aardvarks’ in published materials before July 2008” as a source but because it is not technically false. On the Internet, at least, coatis are, in fact, occasionally known as Brazilian aardvarks, and there are numerous references to prove it.

Taxonomically speaking, this is unfortunate. The coati has no more relation to an aardvark than to any other vertebrate, so the name is misleading. But language, unlike taxonomy, is particularly susceptible to Wikiality. The nickname began because Breves wanted to retroactively prove that he had seen some kind of aardvark at Iguazu Falls. He was more successful than he ever could have imagined. Search YouTube for “coatis at Iguaçu Falls,” and you’ll get an amateur video, posted by someone Breves has never met, titled “Coati - (Brazilian aardvark) at Iguaçu Falls, Argentina.” Breves made his own reality, and, thanks to Wikipedia, we’ve all accepted it.

Photograph by Wayne Lynch/Getty.