Habitat Atlas for Wildlife at Risk
Fringed Myotis
Myotis thysanodes

• Total length: 9 cm; wingspan: 28 cm; ears: 2 cm long.
• Weight: 7.0 grams.
• Dorsal fur is pale brown; underside fur is much paler.
• Outer edge of the tail membrane has a distinct fringe of small, stiff hairs that can be seen with the naked eye.

Status:

British Columbia Blue List
Canada: Vulnerable

Special Significance

This species is at risk because of its small British Columbian population, vulnerability to disturbance and low reproductive rate. Further research is required to determine the roosting habits, diet and seasonal movements of the Fringed Myotis. Unfortunately, bats tend to be viewed as undesirable by many people, when in fact they perform invaluable ecological roles, such as keeping insect populations in check. Conservation of riparian areas, which support a diversity of insects, is an important factor in helping to ensure the continued survival of this species.

Distribution

• Limited distribution in British Columbia, restricted to the arid, low elevation valleys of the dry interior including the Okanagan, Similkameen, Thompson, Fraser, Chilcotin valleys and the Williams Lake region.
• Elevational range is 300 to 800 metres.
• Found nowhere else in Canada.

Habitat

• Fringed Myotis use caves, mines, rock crevices and cliffs, wildlife trees, and buildings for day retreats and night roosts.
• Bats are associated with arid grasslands and ponderosa pine-fir forests.
• Riparian areas along lakes, streams and rivers are presumably important foraging areas for the Fringed Myotis.
• Nursery colonies are usually located in cliffs; loose bark in ponderosa pines may also be important maternity sites.
• Scant information on hibernating sites suggests this species may migrate only short distances to cave hibernation sites; may hibernate in inaccessible rock crevices.

Reproduction

• Breeding occurs in the fall after female bats leave maternity roosts; fertilization occurs between the end of April and mid-May; the gestation period is 50 to 60 days.
• Nursery colonies are established mid- to late April and remain stable until September; female bats give birth in late June or early July.
• Young males are not usually reproductively active during their first autumn; the age when females reach sexual maturity is unknown.
• Young bats develop rapidly and are capable of limited flight at 17 days of age; young attain adult size by the age of 3 weeks.

Food Habits

• Fringed Myotis are late feeders; bats begin foraging an hour or so after sunset.
• Bats eat moths, flies, beetles, leafhoppers, lacewings, crickets, harvestmen.
• Prey is gleaned from tree trunks, branches and leaves, and the ground.

Interesting Facts

• Named the Fringed Myotis because of the conspicuous fringe of hairs on its tail membrane.
• Consistently found in association with many other bat species.

References

1. Nagorsen, D.W. and R.M. Brigham. 1993. Bats of British Columbia. Royal British Columbia Museum Handbook, Victoria, British Columbia
2. Rasheed, S.A., P.F.J. Garcia and S.L. Holroyd. 1995. Status of the Fringed Myotis in British Columbia. Ministry of Water, Land and Air Protection, Lands and Parks, Victoria, British Columbia