Which novel describes human-like creatures known as Yahoos?
And the answer: Gulliver's Travels.
Written in 1726 by Irish author Jonathan Swift, Gulliver's Travels is a satirical look at human nature, as well as a parody of travel books. The novel is split into four sections, the last of which describes the Land of the Houyhnhnms, where horses rule over human-like creatures known as Yahoos.
Johnathan Swift was born in Ireland to two English parents in 1667. Born at a time where British-Irish tensions ran high following the English Civil War, Swift turned to literature as a passion and escape from political realities. Most pertinently, Swift excelled at satire, using the humor of satire as an apt way to offer social commentary.
Gulliver's Travels is a travel narrative that follows the journey of a man named Lemuel Gulliver. Gulliver begins his travels through Lilliput, the land of the small people, before going on through Brobdingnag (land of the giants), Laputa (land of the "scientists"), and finally the Land of the Houyhnhnms (land of the talking horses). Swift uses the absurdity of each setting to illustrate a different shortcoming of quite human qualities. For example, in Lilliput, Swift calls attention to people's pettiness as two political parties fight furiously over which end of an egg should be cracked.
Ultimately, Swift obliges English society to ask larger questions about the point of systems of power. Like many other Enlightenment thinkers, Swift urged a reconsideration of what and who could be considered "civilized" while England began to grow in power and contact with the rest of the world.
The novel has since been made into several major motion pictures. Check out the 1939 adaptation below.