Habitat: Ranges from lowlands to 3150 m. Occurs in almost every type of tropical and subtropical forest habitat, including savannas and scrub (Wilson and LaVal, 1974). Distribution: Mexico through Central America and across most of South America to Argentina, Peru, also Trinidad, Tobago. Natural History Notes: Guild 2: Background Cluttered Space/Aerial Insectivores (Kalko, et al., 1996). Perhaps the most studied of the tropical Myotis. Roosts in small to large colonies in caves, hollow trees, buildings. Reproduction involves a post-partum estrus, with birth peaks during the rainy season, especially April-May and August in Panama. Characteristics: Small. Forearm 33-38mm, Mb about 5 gms. Dorsal pelage blackish or brownish, silky, not wooly, underparts lighter. Ears pointed, blackish, as is the face. Hair lacking on uroptagium below level of knee.