Little Brown Bat

Myotis lucifugus

All about the Little Brown Bat (sometimes referred to as Little Brown Myotis)

The Little Brown Bat can be a major pest. If roosting or nesting occurs on, or in a man-made structure, major damage could be done. Bats are known for being carriers of disease and producing unsanitary and malodorous material. If you are unsure what type of bat you have you should contact a professional. the Little Brown Bat can also be a very beneficial species as it feeds on many garden pests.

What does a Little Brown Bat look like?

little brown bat

little brown bat full wingspan 12inches

True to its name, the Little Brown Bat is both small and brown. The bat’s fur is glossy brown with gray fur underneath. The bat’s wing membranes are dark brown and ears are small and short with a rounded targus. Mature Little Brown Bats are between three and five inches long with a wingspan of 9-11 inches. The Little Brown Bat, when fully grown, weighs between 1/16 and ½ ounce. Female Little Brown Bats are larger than the males. They have 38 sharp teeth, with prominent canines to aid them while grasping prey in flight.

The Little Brown Bat may be confused with the Indiana Bat or Long-legged Bat. Distinctions between the two species include hairs on the hind legs that extend past the toes and less amounts of hair under the wings.

Where does the Little Brown Bat live, and what does it eat?

The Little Brown Bat can be found almost everywhere in the United States and southern Canada.There are three main purposes for the Little Brown Bat to roost:  daytime roosting, nighttime roosting, and hibernation roosting. While the bat is active, it will roost day and night in buildings, caves, under rocks or piles of wood, or in man-made structures like houses, buildings, and churches (inside walls, chimneys, fireplaces, attics, shutters, eaves, and bell towers are some of the perfered places). In any of its roosting sites, Little Brown Bats pack closely together to utilize each other’s body temperature. After feeding in the evening, the bats congregate in their nighttime roosts. Little Brown Bats will hibernate during the winter months in a cool, dark, secluded place like an abandoned mine, cave, or attic. These bats prefer insects with aquatic life stages so roosts will often be found near water.

Little Brown Bats are insectivores, which means they feed on various species of insects:  primarily mosquitoes, gnats, mayflies, moths, beetles, and wasps. The bat uses echolocation to find its prey in the dark then tucks it into a pouch made with its wing. Once it’s trapped, the bat will grab the prey and eat it. Little Brown Bats, can be great controls on garden pests. Male Little Brown Bats have been known to eat as much as half their body weight in a night and lactating females more than their body weight.

The Little Brown Bat’s Circle of Life

Mating season for the Little Brown Bat is in the fall, just before hibernation, but fertilization will occur in the spring. Bats will form a nursery colony, or roost, in the spring that may contain thousands of bats. Little Brown Bats are mammalian and therefore give birth to just one baby bat at a time. The female bat will hang right side up while giving birth to a baby bat, then the bat attaches on to its mother for up to three weeks when it is able to fly on its own.

The Little Brown Bat can live as many as 6-7 years and often lives more than 10 years.

Little Brown Bats and Humans

The Little Brown Bat is not known to be hostile towards animals or humans. Most effects on humans are due to its roosting habits, which may affect structures. Bats are nocturnal, so it’s common that most bat activity in and around your home will occur in evening hours when the bats are getting ready to feed.

Professional Little Brown Bat Control

If the Little Brown bat has been found inside human-inhabited structures it should be removed immediately. Because the location and elimination of the roost is not as easy as it sounds, a professional should aid in this process.

  1. On the lookout:  Before locating the roosts of the Little Brown bat, entrance and exit points must be found first. A professional will spend several days (usually at night when most bats leave the roost) observing the structure to identify where bats are coming and going. This will give them a good idea of where the roost is. Common entrances and exits are cracks, openings, or gaps in roofs, attics, or exterior walls.
  2. Tighten up:  Depending on how the bat roost is handled, a professional will most likely set to work sealing up all entrance and exit points but one. One exit will be left for a bat valve or other exclusion device (so bats can come out but not get back in).
  3. Exclusion of the bats is usually done using a bat valve or other exclusion device that guides bats out of the roost with no entrance back into it. Exclusion must be done when all young bats are feeding independently of their mother.
  4. Clean house:  Bat roosts will inevitably leave a trace – normally in the form of bat droppings, urine, and other debris. To keep your home safe from the bacteria such debris may harbor, a professional can thoroughly clean and sanitize the areas in which bats were known to be roosting.
  5. Home Sweet Home:  A great way to conserve Little Brown bat populations is to simply relocate the roost to a bat house. Since this bat is great at controlling insect infestations in your garden, you may not want them too far! A professional can aid in installing the house and re-routing the roost.

DIY and Green Solutions for Little Brown Bat Control

All control measures of the Little Brown Bat should be sensitive to bat populations. This species can actually be a natural control method for garden-devastating insects. That said, bats can also be a danger to humans as their guano and urine are known to carry bacteria and, although it is rare, bats themselves may be carriers of rabies. When employing any bat control on your own, be sure to wear long sleeves, pants, good shoes, gloves, and a mask. The first step in any control method is to locate the roost by closely observing your structure as bats fly to and from it.

  1. “Do Not Pass Go!” Granular Repellents designed to deter bats from roosting sites have been found very effective. Once entry and exit points are identified, the repellent is applied to those locations where bats come and go. This will keep bats from coming back to roost, and will most likely guide them elsewhere.
  2. Netting:  After you locate the entrance and exit points for the Little Brown bat, use the granular repellent to deter bats from coming back to roost, then seal the entrances. This can be done a variety of ways, depending on the size of the opening. Smaller openings can be sealed with urethane foam, larger openings should be closed off with bird netting. Keep in mind that one exit point should remain available for any bats inside the roost to get out.
  3. Exclusion:  Bat valves or other vents are available for purchase at hardware stores. After locating the roost as well as any entrances, seal off all but one entrance and install the exclusion tool according to instructions.

Little Brown Bats are the most common of the bat species in North America, however protection of the species is important. Control efforts for the Little Brown Bat have been concentrated on exclusion rather than use of chemicals or other harmful means of extermination. Conservation of the Little Brown Bat is important, so when seeking to control Little Brown Bats, measures that are least invasive to the species are preferred. Control measures should be employed only after baby bats have reached maturity and are able to fly (this usually happens in mid-summer); otherwise baby bats will be stuck inside your building and create an even bigger problem (guano, dead bats, etc).