The Northern Long-eared Myotis is a medium-size species of Myotis with dark brown fur on its back. The fur on its underside is paler, varying from tawny to pale brown. The ears and flight membranes are dark brown but not black. The ears are long, extending beyond the nose when pushed forward; the tragus is long, narrow and pointed. The edge of the tail membrane is bare or has only a few, scattered hairs. The calcar may have an indistinct keel. The skull is relatively narrow with a long rostrum.
IdentificationThe range of the Northern Long-eared Myotis overlaps with only one other long-eared Myotis species in British Columbia - the Western Long-eared Myotis (Myotis evotis). The Northern Long-eared Myotis can be discriminated by its paler and smaller ears (extending less than 5 mm beyond the nose), the lack of shoulder spots and the sparse fringe of hairs on the outer edge of the tail membrane. Its skull can be distinguished from that of the Western Long-eared Myotis by its shorter toothrow - the distance from the last upper premolar to the last upper molar is less than 4.2 mm.
Dental Formulaincisors: 2/3
Measurementstotal length: 87 (80-94) n = 18
tail vertebrae: 39 (29-46) n = 63
hind foot: 9 (7-11) n = 61
ear: 17 (14-19) n = 56
tragus: 10 (8-12) n = 45
forearm: 36.1 (34.0-38.0) n = 57
wingspan: 234 n = 1
weight: 6.5 (5.0-10.0) n = 33