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Myotis septentrionalis (Trouessart)
Northern Long-Eared Bat; Northern Long-Eared Myotis; Northern Myotis
Family: Vespertilionidae

Species account authors: David Nagorsen and Mark Brigham.
Extracted from the Bats of British Columbia

Introduction to the Bats of BC

Introduction to the Mammals of BC

Distribution of Myotis septentrionalis in British Columbia.
(Click on the map to view a larger version.)

Source: BC Ministry of Environment 2008. (Maps prepared by David Nagorsen.)

The information provided below is extracted from the Bats of British Columbia, and may be dated. Check the status section below for current status information.

Click on the image(s) below to view an expanded illustration for this taxon.

Illustration Source: : Bats of British Columbia by David Nagorsen and Mark Brigham © Royal BC Museum

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.

Identification

The 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 Formula

incisors: 2/3
canines: 1/1
premolars: 3/3
molars: 3/3

Measurements

total 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

Reproduction

Mating usually takes place at the hibernaculum in autumn; females produce a single young. The only available breeding datum for British Columbia, a female with a six-millimetre embryo found on 16 June, suggests that young are born in late June or early July.

Diet

This species emerges at dusk to hunt over small ponds and forest clearings under the tree canopy. In Mount Revelstoke National Park Northern Long-eared Myotis were observed regularly at dusk drinking from small pools in forest clearings. Much of this species' hunting activity takes place just above the understory one to three metres above the ground. Its diverse diet includes caddisflies, moths, beetles, flies and leafhoppers. Some prey may be gleaned from twigs and foliage.

Natural History

No roosts have been found in the province. In eastern North America summer day roosts and nursery colonies have been found in buildings and under the bark of trees; all nursery colonies were small, comprising no more than 30 individuals. Caves may be exploited for temporary night roosts.

There are no winter records for the province. However, in other parts of North America, the Northern Long-eared Myotis hibernates in caves and abandoned mine tunnels. Swarming behaviour begins in late summer or early autumn and movements of up to 56 kilometres between the summer roost and the hibernaculum have been documented. This species appears to be a late hibernator; in eastern Canada it arrives at hibernacula two to eight weeks after the Little Brown Myotis enters hibernation. The Northern Long-eared Myotis hibernates alone or in small clusters, selecting tight crevices or drill holes where temperatures may be as cool as 1.6°C. Although this species and the Little Brown Myotis often share hibernacula, they are rarely found touching while hibernating.

In Canada the Northern Long-eared Myotis is generally associated with boreal forests. Information on habitat in British Columbia is limited to Mount Revelstoke National Park where it has been found in Western Hemlock - Western Red-cedar forests at about 700 metres elevation.

This bat is distributed across the eastern United States and Canada west to the southern Northwest Territories and eastern British Columbia. There are only three substantiated locality records for the province: Hudsons Hope in the Peace River area, Mount Revelstoke National Park and the Revelstoke Dam. It might also occur in Glacier and Kootenay national parks: echolocation calls resembling those of Northern Long-eared Myotis were recorded in both parks during bat surveys with electronic bat detectors; but echolocation calls of the Northern Long-eared Myotis and the Western Long-eared Myotis cannot be discriminated with certainty using a narrow band detector.

One of the rarest bats in the province, the Northern Long-eared Myotis is on the provincial Red List. The first record for this mammal in British Columbia was collected at Hudsons Hope in 1931. In June 1979, a second specimen was collected on the Giant Cedars Trail in Mount Revelstoke National Park. In subsequent field work in 1981 and 1982 more individuals of this species were trapped and released at this site. An individual was found dead in the powerhouse of the Revelstoke Dam in 1980. With records as far north as Nahanni National Park in the Northwest Territories, it seems likely that the Northern Long-eared Myotis is a regular inhabitant of the extreme northeastern region of the province.

Origin Status	Provincial Status	BC List (Red Blue List)	COSEWIC
Native	S3S4	Blue	E (Nov 2013)

BC Ministry of Environment: BC Species and Ecosystems Explorer--the authoritative source for conservation information in British Columbia.

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