The fur of the Silver-haired Bat is dark brown or black with scattered silver-white-tipped hairs giving it a lightly-frosted appearance. Old individuals tend to have fewer white-tipped hairs and their fur often appears pale brown or yellowish. On the underside, the frosted hairs are concentrated in the belly. The ear is short and round with a short, blunt tragus. The ears and wing membranes are black. The dorsal surface of the tail membrane is lightly furred. The calcar lacks a keel. The skull has a blunt rostrum and is flat in profile.
IdentificationThe only Canadian species this bat could be confused with is the Hoary Bat (Lasiurus cinereus), but the Silver-haired Bat is much smaller (forearm less than 44 mm). Also its light covering of fur at the base of the tail membrane contrasts with the thickly furred dorsal surface of the Hoary Bat's tail membrane. Among British Columbian bats, only Townsend's Big-eared Bat (Plecotus townsendii) has the same dental formula. The skull of the Silver-haired Bat can be readily distinguished from that of Townsend's Big-eared Bat by its flat profile.
Dental Formulaincisors: 2/3
Measurementstotal length: 100 (90-117) n = 68
tail vertebrae: 41 (31-50) n = 70
hind foot: 9 (6-11) n = 69
ear: 12 (9-15) n = 17
tragus: 7 (4-8) n = 22
forearm: 41.4 (39.1-43.9) n = 56
wingspan: 291 (200-354) n = 38
weight: 9.0 (5.8-12.4) n = 14