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Little Brown Bat



Photo: Scott Berges 

Whoever said 'bats are scary' clearly doesn't see very well. I may only come out at night, but I am completely harmless to humans. In fact, while you are settling in for the night, I am just getting started. I use echolocation to find and eat up to 1,200 insects in an hour, saving you from those pesky bug bites. And do you know how hard it is to hunt for tiny insects in the dark, without using sight? Not hard at all! At least not for me. 

I can help you keep bug bites at bay if you help me out too.

As the name suggests, the little brown bat (Myotis lucifugus) is small, weighing as little as a few nickels. Its colors range from brown, reddish, golden and in some cases, albino. The little brown bat has an average lifespan of six to seven years.

White-nose syndrome, a fungal disease that affects hibernating bats, is the main reason behind its population decline, killing more than 90% of little brown bats in some areas. Other threats include habitat loss, pesticide use, and mining. 



  • Little brown bats hibernate for months in caves where the temperature is just above freezing.

  • To prevent malnourishment, they must eat half their weight; pregnant females must eat more than their weight in food. 

  • Moms roost together in huge maternity colonies, and can identify and locate their pups by scents and calls among thousands of pups in a maternity colony.


    Although some mammals can glide, bats are the only mammal that can truly fly. The little brown bat can even fly while eating.

  • Bat calls are ultrasonic, which means they occur at a frequency that is higher than humans can hear.



Help conserve little brown bats by protecting roost sites or by installing a bat house on your property.

Little brown bats need safe places to roost and raise their young during the summer months. Learn more about how to build and install a bat house.



Chicago Wilderness works with our lead partner, Lincoln Park Zoo, to drive little brown bat conservation efforts. They, in turn, coordinate with numerous other organizations across the region. The little brown bat conservation effort is part of the Chicago Wilderness Priority Species Focus Area.


Sources: Lincoln Park Zoo, National Wildlife Federation