Myotis riparius is a vespertilionid bat commonly called the riparian myotis. It is a medium-sized bat, with woolly fur; color of dorsal fur varies geographically from a reddish to blackish tinge. M. riparius is widely distributed in the Neotropics, occurring from Honduras southward into South America to Paraguay, northern Argentina, and Uruguay. It occurs in rainforests, savannas, and open habitats, at elevations from sea level to about 2,000 m. It is listed as “Least Concern” by the International Union for Conservation of Nature and Natural Resources.