As famous as gorillas are today, there was a time in which they were no more tan a myth. Explorers would return from African jungles and tell stories about hairy, giant man-beasts of terrible strength and temper, with a nasty habit of abducting and raping women! Such stories were dismissed by scientists as nonsense, and as a result, the gorilla was unknown to science until quite recently. It is believed that the first gorilla report comes from Greek explorer Hanno, from the 5th century BC. Hanno traveled to the western coasts of Africa, possibly to Sierra Leona or even the gulf of Guinea, and reported “an island filled with savage people, most of them women, and covered on hair. Our interpreters call them gorillae”.
Maybe we should mention that not everyone is convinced about Hanno having encountered actual gorillas (his gorillae could have been chimpanzees). Much later, in 1625, British explorer Andrew Batell reported seeing a “monster” covered on hair except for the face and hands, which slept in trees and fed on fruit. According to him, this “monster” was most similar to a man, but “with the stature of a giant”. Gorillas remained obscure and poorly understood for many more years, being often thought of as brutish, unintelligent and extremely violent. It wasn’t until 1847 that a westerner (physician Thomas Savage) managed to obtain several gorilla bones, including a skull, while in Liberia, and published the very first formal description of the great ape. The next decade, explorer Paul du Chaillu became the first modern European to see a live gorilla during his expeditions to equatorial Africa. As for the mountain gorilla, a different, larger species, it was believed to be a myth until 1902!
Source: http://listverse.com/2010/04/16/10-beasts-that-used-to-be-mythical/