A Yahoo is a legendary being in the novel Gulliver's Travels (1726) by Jonathan Swift.
Swift describes them as being filthy and with unpleasant habits, resembling human beings far too closely for the liking of protagonist Lemuel Gulliver, who finds the calm and rational society of intelligent horses, the Houyhnhnms, greatly preferable. The Yahoos are primitive creatures obsessed with "pretty stones" they find by digging in mud, thus representing the distasteful materialism and ignorant elitism Swift encountered in Britain. Hence the term "yahoo" has come to mean "a crude, brutish or obscenely coarse person".
American frontiersman Daniel Boone, who often used terms from Gulliver's Travels, claimed that he killed a hairy giant that he called a Yahoo.
Yahoos were referred to in a letter sent by serial killer David Berkowitz to New York City police while committing the "Son of Sam" murders in 1976. 
See also 
- ^ Collins Dictionary
- ^ Did fiction give birth to Bigfoot? by Hugh H. Trotti
- ^ http://www.google.com/search?q=%22.I.don't.belong.on.Earth-Return.me.to.Yahoos%22
- ^ http://books.google.com/books?id=SZTPdM97kq0C&pg=PA124&lpg=PA124&dq=%22.I.don't.belong.on.Earth-Return.me.to.Yahoos%22&source=bl&ots=7A3rWrthPO&sig=fOiEiNmDbvbVTg0vCumobbrmQbs