The little brown bat is the most common and widespread of Canada's nineteen species of bats. They are found across Canada to the northern edge of the boreal forest. Little brown bats weigh only seven to fourteen grams and have a wingspan of 22-27 centimetres. This species of bat is the one most closely associated with humans, as it is the most likely to take up residence in buildings.
(Please note — these photos are unverified images submitted by members of the CWF Photo Club.)
Habitat: Even though Little Brown Bats do not usually migrate to destinations outside of Canada, individuals can move up to 1000 km from summer roosts to winter roosts where they hibernate. These winter roosts are called hibernacula. Hibernacula are generally in caves or abandoned mines, and are chosen for their high humidity and stable, above-freezing temperatures. The Little Brown Bat is a true hibernator (it slows down its metabolism, heart rate, and breathing).
Summer roosts can be a building for their maternity colonies but they they also use tree cavities or other places that stay dark and warm during the day, like bat boxes.
Diet: Little Brown Bats feed on a great variety of small, flying insects. They locate these insects using echolocation. These are typically moths, flies, mosquitoes, mayflies, beetles, and midges, but they are opportunistic feeders, meaning that they feed on whatever insect species is available.
Most Little Brown Bats of more than one year old will mate in the fall when great groups swarm together. Individuals can mate several times with different partners. Females will store the males’ sperm throughout the winter until they ovulate in the spring.
After a gestation of 50 to 60 days, depending on the condition and age of the female, a single pup is born in June or July. It is born able to cling onto the roost’s wall and its mother. Little Brown Bat pups can fly at about three weeks old, after which it feeds both on its mother’s milk and insects. It is weaned from its mother’s milk at around 26 days, after which it accumulates fat for the winter before leaving for fall swarming sites.
By Maria MacRae
The little brown bat is the most common and widespread of Canada's nineteen species of bats. They are found across Canada to the northern edge of the boreal forest.
One of the smaller Canadian bats, little browns weigh only seven to fourteen grams and have a wingspan of 22-27 centimetres. This species of bat is the one most closely associated with humans, as it is the most likely to take up residence in buildings.
Little brown bats play an important role as predators of night flying insects. They are very efficient hunters capable of catching over 1000 insects in just one hour. Little brown bats concentrate on insects that have an aquatic larval stage, such as mosquitoes, midges, and mayflies. Consequently, they prefer roosts in the vicinity of water. Although they prefer to forage over water, they will also hunt in open areas where they catch moths, beetles, and other flying insects.
Contrary to the myth that bats are blind, little brown bats have excellent vision. Although echolocation is important, they also use visual cues, especially during long distance migration. Echolocation, the use of high frequency sounds to navigate, is used for finding and catching prey. Their skill in echolocation is such that they are able to avoid obstacles as fine as a human hair. (It is a myth that bats get caught in human hair.)
There are a number of predators that feed on little brown bats, such as raccoons, hawks, owls, and snakes. They are dependant, therefore, on finding roosts that provide protection from these predators while still being close to food and water sources. Little brown bats form a strong attachment to their maternity site and will return year after year to the same location.
In the winter, little brown bats move to caves and mines for hibernation. They find an area of the cave with high humidity and a constant temperature slightly above freezing. Forced to survive the winter on their stores of fat, bats slow their heartbeat from approximately 200 beats per minute to as low as 20 beats per minute to conserve energy. It is important that they are not disturbed while hibernating as this causes them to waste precious fat reserves. Extra arousals can leave them with insufficient energy to survive the winter.
Pesticides harm bats through direct contact and by limiting their food supply. Some farmers have been able to reduce their dependence on pesticides by welcoming bat colonies to their land. They provide artificial roosting sites for the bats, which in turn devour insect pests.
If you would like to help bats in your area you can provide roosting sites by putting up a bat house. Little brown bats are one of the bats most likely to use bat houses.
This content is from Hinterland Who's Who, a joint program between the Canadian Wildlife Federation and Environment and Climate Change Canada. For more species fact sheets, videos and sound clips, please visit hww.ca