| Jun 12, 2008

Outdoors - June 12, 2008

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Outdoors in the LandO'Lakes - June 12, 2008 The Little Brown Bat – Acrobat of the Air Outdoors in the Land O'Lakes by Lorraine Julien

Though there are many birds (even other insects) and mammals that eat insects, one of the smallest insect-eating mammals is the Little Brown Bat. Bats are warm blooded, long-lived mammals and their species make up almost one quarter of all mammals on earth. They are also the only mammal capable of true flight.

This tiny bug eater measures, at most, 3.5” (9 cm.), has a wing spread of 9” (23 cm.) and weighs up to 0.4 oz. (12 g.). It’s found in all the forested regions of Canada wherever there is an abundance of insects.

Because it is so small, the Little Brown Bat can make a home in the warm, cozy attics of houses, churches, barns and other outbuildings, not to mention dead trees and any other nooks and crannies it can squeeze into. The females form maternity colonies which can number anywhere from a few to thousands. Single males also roost in buildings but will also shelter in rock crevices or beneath shingles or the bark of dead trees. These dwellings are only temporary since this little bat moves to its winter quarters, usually a cave, where it hibernates until spring. Just before hibernation, the bats mate and then, anywhere from late May to early July, each mother bears a single infant … twins are rare. The baby is born into a sac-like membrane between the back legs of the female and is nursed in much the same way as other mammals.

From personal experience, I know these bats can fit into the tiniest spaces (less than ”), even between siding and shutters – especially if the shutters are dark coloured and face south or west. The hotter the better! We tried to replicate this same type of accommodation using a south facing bat house mounted on a tree several feet above the water; however, after many years, we’ve been unable to entice any inhabitants.

If you do encounter bats in your house, it is best to try to remove them humanely. It is easier said than done but you can check out information on websites such as the Bats Canada website at www.batscanada.com.

This little acrobat travels through the night sky with the reeling flight patterns indicative of all bats. Their aerial antics are quite fascinating to watch. They are able to fly in such a way as they navigate using a type of sonar called echolocation: when in flight, bats emit a series of high frequency cries, up to 50,000 vibrations per second, far beyond the range of the human ear. The returning echoes made when the sounds strike trees, wires or other obstacles are picked up by the bat’s ears enabling it to avoid even things such as closely spaced wires.

For centuries there have been tales about bats that are quite interesting but mainly erroneous:

The myth that bats get caught in people’s hair is just that – a myth. In fact, bats are gentle creatures that only attack their prey – insects. In the past bats have been linked to witches and evil.The expression “blind as a bat” is completely untrue – in fact, bats can see in daylight or at night.

The Little Brown Bat likes to eat mosquitoes, flies, beetles, etc. – as many as 500 insects in an hour or 3000 insects every night! Another interesting statistic is that 100 Little Brown Bats can consume more than million mosquitoes and other small insects each night. Larger insects such as moths are usually eaten by its larger cousins.

Diseases: Some of us are concerned about bats having rabies but all animals can contract this deadly disease and bats are no exception. However, in bats that have been caught and sent to labs for rabies testing, only 5-10% carries the disease. The actual incidence of bats having rabies is fairly rare, perhaps 0.5% in the bat population, according to the Bats Canada website. Another mysterious disease that is spreading through the north eastern U.S., is “white nose syndrome” which is a powdery white fungus on bat noses. It is thought this could be caused by bats eating pesticide-laden insects but the exact cause is not yet known. I don’t know if this has reached Eastern Ontario yet.

Please feel free to report any observations to to Steve Blight at This email address is being protected from spambots. You need JavaScript enabled to view it. or Lorraine Julien at This email address is being protected from spambots. You need JavaScript enabled to view it.

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