When Mark Twain was a young man he traveled all across the United States. When he was in his mid-thirties he traveled to the West and witnessed the nation as it was growing and moving across the country. He tried out his hand at silver mining, he saw land speculation and he even set fire to a mountain. In the book he describes his encounter with a coyote in the wild. Twain devotes 5 pages to a description of this animal, saying the coyote is "always poor, out of luck and friendless. The meanest creatures despise him and even the fleas would desert him for a velocipede. He is so spiritless and cowardly that even while his exposed teeth are pretending a threat, the rest of his face is apologizing for it."
His entire description of the coyote is so detailed, and so particular, that it's no surprise that it would at some point be turned into a cartoon character. And that's exactly what animator Chuck Jones did. The famous character Wile E. Coyote, from the Road Runner cartoons, comes from Mark Twain's description that Jones read when he was 7. Mark Twain's writing made such an impression on Jones that he would eventually turn it into the cartoon character that so many of us loved as children.
"Along about an hour after breakfast we saw the first prairie dog villages, the first antelope, and the first wolf. If I remember rightly, this latter was the regular coyote (pronounced ky-o-te) of the farther deserts. And if it was, he was not a pretty creature or respectable either, for I got well acquainted with his race afterward, and can speak with confidence." -Mark Twain