Big brown Bat

The big brown bat is between 10 and 13 cm in length, weighs between 14 to 18 grams and has longer glossy chocolate brown fur on the back with slightly paler, greyish fur underneath. The wing membranes are dark brown to black with a typical wingspan of 30 cm.

Major Risks & Dangers

Though bats are very beneficial to the environment, they are not for your residential, recreational or commercial property. A bat living in your home will excrete its body weight in droppings (guano) and urine.. The combination of guano and urine can create strong offensive odours, transmit potentially life threatening diseases, and deteriorate almost any building material it contacts causing considerable damage to your property.

Health risks

There are two major health concerns associated with bats; Rabies and Histoplasmosis. Rabies is a virus that is fatal if untreated. This virus is found in the infected animals’ saliva and is typically transmitted by a bite or through an open wound. Most bat bites are undetected.

If you find a bat in a room that someone has slept in, you should have that bat tested for rabies through the Local Health Department. If the bat cannot be collected for testing, do not take a chance, have the rabies exposure shots administered by a doctor.


The big brown bat’s mating season is in the fall, however, fertilization happens in the spring. When they arise from hibernation in the spring, the females form nursery colonies which may consist of thousands of bats. Gestation lasts between 50–60 days. The female gives birth to one baby each year, sometimes twins, born between May and July. The young cling and feed from their mother constantly until they are two weeks old. At three weeks, they learn to fly and by four weeks, the young are adult sized.

Eating Habits

Big brown bats are insectivorous, eating many kinds of night-flying insects including mosquitoes, moths, beetles, and wasps, which they capture in flight.


To reduce the risk of bats nesting in your residential, recreational/cottage or commercial property, bird proofing/exclusion is the best prevention.

Greenshield Pest Control Inc. can provide you with many bat exclusion/proofing services and solutions.

CLICK HERE to see our Bat Control Proofing /Exclusion Services and Solutions.

As there are  dangers associated with bat bites and feces, it is best  to never attempt to exclude a bat infestation yourself.

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