Little Brown Bats

The Little Brown Bat looks identical to the Big Brown Bat except for the difference in size. The Little Brown Bat has blackish-brown fur on the back and grayish fur on the underside. Typically, Little Brown Bats live 7 to 10 years in the wild but have been recorded to live up to 31 years in captivity. The population of Little Brown Bats is the highest of all bat species in Maryland. They have average eye sight, despite a common belief that they are nearly blind. However, they don’t have night vision like some other nocturnal animals, so they rely on echolocation to find food as they go hunting several times at night.


Physical Description

  • Forearm — 1.34 to 1.61 inches (3.4 to 4.1 cm)
  • Wingspan — 9.02 to 10.59 inches (22.9 to 26.9 cm)
  • Ears — 0.55 to 0.63 inches (1.4 to 1.6 cm)
  • Weight – approximately 1/4 oz.


The Little Brown Bat is common throughout most of North America. It is found from western Alaska, to most of California, central Arizona, across the Rocky Mountains and the Mid-West, as well as along most of the East Coast. This bat is not found in most of the southern states along the Gulf of Mexico, southern Great Plains and much of the south-eastern Coastal Plain.

The Little Brown Bat lives in a variety of man-made and natural structures like hollow trees, under bridges, behind shutters, in attics, chimneys, slate roofs, loose shingles, barns, behind loose siding, and any other area it can squeeze into.


Little Brown Bats hibernate during the cold winter months from September or October through April or May. The exact time when they fall asleep and emerge depends on the temperatures. In mid-fall, they leave their summer roosting site and fly from a few miles to a few hundred miles to their hibernation site. This hibernation site must be cool but remain above freezing. Often, these bats are found roosting and hibernating with the Big Brown Bat.

Reproduction and Mating

Females reach sexual maturity at 8 months old, while males do not reach sexual maturity until their second summer. Little Brown Bats mate in the fall during the journey to their hibernating roost. However, the females do not become pregnant until the following spring when they fly back to their summer roosting site. During mid to late spring and early summer, females gather in nursery colonies that can range from a few bats to thousands of bats. Females give birth to one pup in June or July. The pup stays with mom for about 4 weeks, at which time the pups are able to fly and feed on their own. Males are solitary when females gather in maternity colonies to raise pups. Males will roost in hollow trees, under loose shingles and siding, or any other suitable structure.


As Little Brown Bats emerge from their day-time roost around dusk, they seek out a body of water and skim the top for a drink. They also like to roost close to water because water attracts a wide variety of flying insects such as mosquitoes, flies, beetles, and moths. Each night the Little Brown Bat leaves their roost and makes several feeding flights. Just like most mammals, including other bat species and humans, the Little Brown Bat will eat until it is full and then a few hours later it will be hungry again—it’s like having breakfast, lunch and dinner. These impressive little bats can eat up to 1,200 insects a night.

If you have a colony of Little Brown Bats in your attic, contact us to schedule an inspection with a bat expert. Our Wildlife Control Technicians can humanely evict the bats and seal up any existing or potential entry points to prevent bats from re-entering your home.