This article examines the word histories of 12 nouns (eight zoonyms, two other lifeform names, and two toponyms) in Mixtec, a shallow or emergent language family of Mesoamerica. It argues that these nouns—now morphologically opaque—are fused compounds that arose from the Mixtec vocabulary of the mantic count of 260 days, a temporal organization that was part of the common cultural heritage of pre-Hispanic Mesoamerican peoples. With the European colonization and persecution of Mesoamerican religious practices, the use of the mantic count was abandoned. It was at this time that the compounds would have been demotivated; that is, the internal morphological structure would have become inaccessible to speakers who could no longer relate it to the mantic cycle. This then enriched the lexicon, creating etymological pairs for the same, or similar, referents. It is suggested that the survival of the eight zoonyms may have to do with their use in the context of omens.