“Muskrat” is a traditional old-time song, a comic novelty number of the kind common in early string-band music. It has no known author; it was carried in oral tradition and reached records in the 1920s.
The song was introduced on disc by Uncle Dave Macon, the banjo-playing showman known as the “Dixie Dewdrop,” who became the first great star of the Grand Ole Opry. The lyric is a string of playful questions put to a parade of animals — the muskrat, the groundhog, the rooster, and others — each asked, in turn, to account for some odd trait. That kind of light, joking catalog was a staple of old-time entertainment.
The song stayed alive among old-time and bluegrass musicians as a cheerful change of pace.