Vespertilionidae Author Don E. Wilson Author Russell A. Mittermeier text 2019 2019-10-31 Lynx Edicions Barcelona Handbook of the Mammals of the World – Volume 9 Bats 716 981 book chapter 56755 10.5281/zenodo.6397752 45351c32-25dd-422c-bdb2-00e73deb4943 978-84-16728-19-0 6397752 176. Common Big-eared Brown Bat Histiotus macrotus French: Sérotine a grandes oreilles / German: Gewohnliche GroRohrfledermaus / Spanish: Histiotus orejudo Taxonomy. Nycticeius macrotus Poeppig, 1835 , Antuco, Bio Bio, Chile . Histiotus laephotis has been previously considered a subspecies of H. macrotus . It is frequently mistaken with H. laephotis and H. montanus , therefore, accurate data from literature are scarce. Monotypic. Distribution. C Chile and NW, C & W Argentina . Records from Peru should be reviewed. Descriptive notes. Head-body ¢.59-65 mm, tail 48-62 mm, ear 28-34 mm, hindfoot 9-11 mm, forearm 45-9-50-9 mm; weight 10-3-20 g. Dorsal hairs of the Common Big-eared Brown Bat are strongly bicolored, with black or dark brown bases and yellowish tips; ventral hairs have dark brown bases and yellowish white tips. Ears are extremely large; tragusis well developed. Membrane connecting ears is poorly developed. Membranes, face, and ears are brown to dark brown, notably darker than body. Skull is robust; rostrum is wide; sagittal and lambdoidalcrests are practically absent; zygomatic arches have strongly developed postorbital process ofjugal; palate is slightly concave centrally; caudal spine is well developed; and tympanic bullae are large and rounded. Habitat. Great variety of habitats ranging from deserts to montane rainforests, including Dry Chaco , Espinal, Yungas, Patagonian forests and steppes, temperate forests, moist montane Chacoan forests, desert and rocky canyons, and mature forests at elevations of 240-3600 m. Common Big-eared Brown Bats have been captured over streams, ponds, and irrigation canals. Food and Feeding. Common Big-eared Brown Bats are insectivorous. Feces contained fragments of Lepidoptera (36-6% by frequency), Coleoptera (30-6%), Trichoptera (13.6%), Diptera (9-8%), and Acari (1-7 %). Breeding. In Rio Negro, Argentina , pregnant and lactating Common Big-eared Brown Bats were captured in December; pregnant females carried only one embryo. Activity patterns. Common Big-eared Brown Bats usually roost in mines, natural caves, buildings, and rocky crevices. Movements, Home range and Social organization. The Common Big-eared Brown Bat is usually solitary in central Chile , but in other parts ofits distribution, colonies from 20 to hundreds of individuals were found. It will share roosts with Brazilian Free-tailed Bats ( Tadarida brasiliensis ) and Myotis spp. Status and Conservation. Classified as Least Concern on The IUCN Red List. The Common Big-eared Brown Batis widely distributed, presumably with large populations. It is relatively common in northern Chile but seems uncommon in Argentina . Bibliography. Aragon & Aguirre (2014), Barquez & Diaz (2016a), Barquez et al. (1999), Giménez (2010), Giménez et al. (2015), Handley & Gardner (2008), Lopez-Gonzélez et al. (1998), Mann (1978), Mares et al. (1995), Simmons (2005).