Little Brown Myotis

Little Brown Myotis – Photo credit S.Dobbyn

Myotis lucifugus

Note- Formerly named Little Brown Bat


  • COSEWIC – Endangered
  • COSSARO – Endangered


  • True to its name, the Little Brown Myotis weighs only 4-8 grams and is approximately 4-5 cm long.
  • The overall colouration is brown and they are slightly buffy- gray underneath. The wings are tinged bluish-gray.


  • They forage typically over water and their diet consists mainly of aquatic insects such as midges, mosquitoes, mayflies, and caddisflies.
  • Three different roosting sites are used: day roosts, night roost and hibernation roosts.
  • The Little Brown Myotis leaves its roost at dusk and the next two or three hours are peak activity periods. They are also active before dawn.


  • They typically produce only one pup each year. Little Brown Myotis start breeding after one year and have been recorded to live over 30 years.
  • In summer, the males and females live apart while the females raise the young. When fall comes, both sexes fly south to a hibernaculum, where they mate and then hibernate.


  • Little Brown Myotis use a wide variety of forest habitat and readily makes use of man-made structures.


  • White-nose Syndrome (WNS) has led to catastrophic declines of bat populations in north-eastern North America.  WNS is caused by a fungus that likely originated in Europe. It grows in humid, cold environments, typical of caves where bats hibernate.
  •  It was first identified in a cave near Albany, New York in 2006.  By 2010, WNS was confirmed in Ontario. The mortality rates at infected hibernation sites in Ontario, Quebec and New Brunswick are over 80%.
  • WNS is expanding in Canada at average rate range of 200-400km/yr. If the spread of WNS continues at the current rate, the entire Canadian population would likely be impacted within 11-22 years.

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Conservation Actions:

  • Please report any unusual bat activity such as flying outside in daytime or deaths to the Ministry of Natural Resources at 800-667-1940.
  • You can help reduce the spread. Do not enter non-commercial caves and abandoned mines where bats may be present.