The big brown bat has a vast range, that extends from northern South America to southern Canada. In British Columbia, it is found on Vancouver Island, the coastal mainland north to the Bella Coola River Valley, and into the interior. Its northern-most habitats in BC, are in the Prince George and the Peace River region. A recorded sighting from the interior of Alaska, though, indicates their range may extend even further north than originally thought.
While many mammals are able to glide, bats are the only mammals capable of true self-powered flight. The only other groups of animals to have achieved this skill, are insects and birds.
The big brown bat’s ability to fly is even more impressive, because they are, as their name suggests, bigger than most bat species. These bats typically weigh about .25 kg and are from 12 to 14 cm in length.
Big brown bats are nocturnal animals and fly only at night. They have developed a means of seeing in the dark, known as echolocation – very similar to sonar. Bats release ultrasound waves from their mouths or noses and receive a return echo bouncing off surrounding objects, including prey, such as moths. You can sometimes hear their high-pitched sounds when chasing moths near a light source.
During the day, big brown bats roost in trees, caves, or old buildings. These bats, like some other animal species, are known to hibernate during the winter months. Hibernation involves a period of reduced metabolism, allowing bats to reduce their energy requirements during harsh winter months when little food is available.
Mating season for big brown bats starts in November and may continue all the way to March. Females that are carrying young will leave their home roost, and form a maternity roost.