In Our Backyard: Little Brown Bat


At this time of year, you typically won’t spot this bat species unless you are exploring abandoned mines and dark caves where they hibernate during the cool months. The little brown bat (Myotis lucifugus) is a vulnerable bat species inhabiting most of North America. It is one of 19 bat species found in Canada and inhabits nearly every province and territory, besides Nunavut, and every region in BC including the Thompson, Okanagan and Kootenays. This species is listed as endangered nationally and in BC they are classified as a species of special concern.

This species heavily relies on cliffs, rock crevasses, trees, abandoned buildings, and piles of wood for summer roosting habitat during breeding season. During this period, effective foraging habitat is critical to their survival as they can eat half of their body weight in insects each night and females that are nursing can eat more than their body weight in prey. Little brown bats typically hunt over streams, along riverbanks, and on the edges of woodlands surrounding waterways as these open habitats allow the bats to hunt most effectively using echolocation. The combined needs of cliffs, caves, and riparian habitats, makes the Thompson Watershed prime habitat for this species.

Despite their small size and mass (weight: 7-9 grams), bats of this species are known to live up to 30 years.

It is while hibernating that little brown bats are most susceptible to white-nose syndrome, a fungal disease that thrives in cool, wet environments. This disease rapidly spreads through bat colonies and plagues populations by depleting its energy through hibernation, and in some cases leading to regional extinctions. The white fungal growth on their “nose” and wings disrupts their pattern of hibernation, repeatedly awakening them through the winter months, depleting their energy stores and forcing them into a state of starvation before they can forage in spring. Those infected use their energy reserves twice as fast as those unaffected.

The Western Canada Bat Conservation Program led by Associate Conservation Scientist Cori Lausen of Wildlife Conservation Society Canada, leads, implements, and coordinates research and conservation initiatives related to Western Canada’s bats. At the time of publishing this article, white-nose syndrome has been found in Saskatchewan and Alberta but not yet in British Columbia.

We’re in a bit of time crunch. White-nose Syndrome is already on the West Coast — it’s only a matter of time before it gets to BC. It’s this impending feeling of doom that has us working hard to see if we can find the science to prevent it. There’s still a chance that we could potentially save the lives of western bats. – Research Technician Aaron Wong, Thompson Rivers University

Outside of white-nose syndrome, these bats are also highly susceptible to habitat loss and degradation, pollution, climate change, wind turbines, and pesticides. The conservation of this species is important for the economy and ecosystems.

We rely on these animals as critical players in insect control and pollination of many crops and wild flowers. These animals also maintain ecosystems, dispersing seeds across far distances and acting as prey for other vulnerable species like owls, hawks, falcons and small mammals.

Read more about the status of this species of bat in Canada and related species.