Townsend's Big-eared Bat is a medium-size bat with enormous ears - about one half its body length - and two prominent, glandular swellings on its nose. Its long dorsal fur varies from pale brown to blackish-grey; hairs in the underfur are paler. The tragus is long and pointed - about one third the ear length. The calcar lacks a keel. The skull is relatively narrow and the profile of the brain-case is curved.
IdentificationThe Pallid Bat (Antrozous pallidus) and the Spotted Bat (Euderma maculatum) are the only other species in the province with such large ears. The Spotted Bat is readily identified by its distinctive markings and the Pallid Bat is larger (forearm length 45-60 mm); neither have the lumps on the nose. Among British Columbian bats, only the Silver-haired Bat (Lasionycteris noctivagans) has the same dental formula. The flat profile of the skull distinguishes it from Townsend's Big-eared Bat.
Dental Formulaincisors: 2/3
Measurementstotal length: 100 (83-113) n = 52
tail vertebrae: 46 (38-57) n = 44
hind foot: 11 (7-10) n = 51
ear: 34 (27-40) n = 26
tragus: 13 (10-15) n = 11
forearm: 42.6 (39.0-45.2) n = 55
wingspan: 287 (232-313) n = 32
weight: 8.6 (6.0-13.5) n = 15