For a six-day period beginning Aug. 25, 1835, the New York Sun (probably via one of its reporters, Richard A. Locke) made most of America believe such a thing. The Sun claimed the series of articles about moon people was based on a discovery by famous astronomer Robert Herschel. For months, if not years, the Sun and other media milked the supposed discovery for every ounce of sensationalism they could get out of it. The Sun falsely claimed its circulation was boosted by the series. As a result of the hoax, further publications (including translations into other languages), dramatic productions, supposedly scientific dioramas, and many other spin-offs extended its imposition on the public.
Herschel was reportedly amused by the brouhaha until he realized how many people were confusing his process of scientific discovery with the trumped up story pulled off by the Sun.
The Great Moon Hoax of 1835 has gone down in media history as one of the first episodes of widespread mass-media hysteria. You can find a full account at The Museum of Hoaxes web site, including the original news stories about bat-monkey-men, beaver people, blue unicorns, and sacred temples on the moon: http://www.museumofhoaxes.com/hoax/archive/permalink/the_great_moon_hoax.
What explains the hoax’s success? For one, people are fascinated with the idea of sentient beings on other worlds and love to read and think about them. The Great Moon Hoax has also been labeled “America’s First Science-Fiction Story,” but I remember that my elementary school library still had books on the shelves (long after science had discredited such a notion) revealing the amazing “fact” that there were canals on Mars–canals built by Martians! What will Curiosity discover as it creeps across the Martian landscape? Are Martian bat-monkey-men giggling at us just over the next ridge? No, but I’m sure Curiosity discover something else amazing, maybe something beyond our wildest imaginings. Its discoveries will no doubt derive from the realms of chemistry and physics, not bat-monkey-men or canals.
I guess strange creatures could live out there somewhere. Look at brave little Voyagers I and II as they head into deep space past the edges of the Heliosphere. On board each of the Voyagers, golden discs proclaim, to any aliens they may encounter (I’m quoting the words of the Whos in Dr. Seuss’s Horton Hears a Who), “We are Here! We are Here! We are Here! We are Here!” http://voyager.jpl.nasa.gov/
As for bat-monkey-men, we may laugh at our great-grandfathers and -mothers for their credulity as they marveled over their copies of the New York Sun, or gawked at P.T. Barnum’s shows, but aren’t we equally gullible, at least at times? A visit to snopes.com and factcheck.org will quickly show us that we are as vulnerable to swiftboatery, chicanery, malarky, and falderol as our ancesters were. If 20th century history teaches us nothing else, it teaches us that sometimes (too often?) such gullibility is extremely dangerous. The U. S. Office of Strategic Services reported that Adolf Hitler followed this propaganda principle: “people will believe a big lie sooner than a little one; and if you repeat it frequently enough people will sooner or later believe it.” (O.S.S. psychological profile of Adolf Hitler, Hitler As His Associates Know Him, http://www.nizkor.org/hweb/people/h/hitler-adolf/oss-papers/text/oss-profile-03-02.html).