Big Brown Bats

Category:

Actual Size: Body length of four to five inches, with a wingspan of 12 to 13 inches

Characteristics: Copper-colored fur with lighter belly fur. Small round ears that are black. Broad nose and black wings.

Habitat: Found in almost all habitats, from deserts, meadows, and cities, to forests and mountains. Will hibernate in caves and other buildings.

Habits: 

  • Distributed widely across Florida.
  • Insectivorous and prefers to eat beetles over insects.

Big brown bats, known scientifically as Eptesicus fuscus, are one of Florida’s most frequently spotted bat species. Although they help to control insect populations, they can create problems when they seek shelter in homes or buildings. Their tendency to roost in attics or walls, especially in cooler months, can lead to health concerns and property damage. Understanding their behavior, what attracts them, and when to call for help is key to protecting your property.

Characteristics

The big brown bat has copper-colored fur on its back and lighter fur on its belly. Its ears are small, round, and black, matching its broad black wings and nose. Its wings are dark and leathery, enabling efficient flight and maneuverability. Their strong, sturdy jaw muscles are designed to crush the hard shells of beetles, a primary part of their diet. These physical features make this species relatively easy to distinguish from other bats. Big brown bats rely on echolocation (high-frequency sounds) to expertly navigate and locate prey in the dark, making them highly efficient at controlling insect populations.

Identification

Size and color are major clues if you’re attempting to identify this bat species. The big brown bat is generally about four to five inches long, with a wingspan up to 13 inches, tip to tip. Their rich brown fur and compact body shape set them apart from smaller bats, which tend to have softer fur and slimmer builds. Thanks to the width and structure of their wings, flight is controlled and direct; they are often seen just after sunset when they emerge to feed.

Habitat

These bats are found in deserts, meadows, forests, farmlands, cities, and mountainous regions. In Florida, they roost in barns, homes, attics, and under bridges. Unlike other species that migrate long distances, Eptesicus fuscus tends to stay within 50 miles of its summer roosts. They spend winter hibernating in small groups, choosing caves, mines, wall voids, or other warm, sheltered spaces. This is a good time to call in the bat exterminators, who can remove the problem pests without too much resistance. 

Big Brown Bats in Florida

The big brown bat is one of the most widespread species in Florida. Its ability to survive different environments makes it well-suited for both rural and urban areas. They use strong jaws to chew through beetle shells (exoskeletons), although their diet also includes moths, wasps, flying ants, and other insects. This makes them helpful for reducing agricultural and garden pests. Depending on available shelter, colonies can be small or reach into the hundreds. Though the average lifespan is over six years, many do not survive their first hibernation due to malnutrition or environmental stresses.

Big Brown Bat Behaviors, Threats or Dangers

As nocturnal mammals, they hide in roosts during the day and come out at night to hunt. A key behavioral trait of big brown bats is site fidelity. Females typically give birth to a single pup each year and return to the same maternity roosts. Knowing this helps guide humane exclusion timing, especially since their presence inside buildings can cause problems. Noise, guano buildup, and the risk of disease transmission make professional intervention necessary. While big brown bats are not aggressive, they can carry rabies. Although they do not typically interact with humans, handling them directly is not advised. If you find a bat indoors or suspect a colony, it’s best to call a trained technician.

Are Big Brown Bats Hard to Get Rid of?

Removing big brown bats can be tricky because they can squeeze through openings as small as half an inch wide and can roost in hard-to-reach areas. Their habit of returning to the same spot each year means exclusion must be thorough and long-lasting. Sealing entry points and using one-way doors to allow bats out but not back in are standard methods used by professionals. While common and widespread, big brown bats face threats from habitat loss and diseases in some regions. This makes humane and regulated exclusion important to balance control and conservation.

How Many Big Brown Bats Count As An Infestation?

Even a handful of big brown bats living inside a structure should be taken seriously. A colony of 20 or more can produce large amounts of guano and noise. This can gradually affect air quality and potentially cause structural damage. Signs of an infestation include droppings, greasy marks near entry points, and scratching or squeaking sounds. A thorough inspection by a pest control expert can help determine the size and location of the colony.

 

 

Frequently Asked Questions

 

Where Do Big Brown Bats Typically Roost?

They prefer sheltered spaces like attics, barns, bridges, hollow trees, and wall cavities. These locations offer protection from the weather and predators.

Are Big Brown Bats Dangerous To Humans?

While they are not aggressive, big brown bats can carry diseases. You should never try to handle a bat yourself. Contact with guano or a bite should be followed by a visit to a healthcare professional.

Are Big Brown Bats Protected By Law?

In many regions, bats are protected during certain times of year, especially during the maternity season. Always consult with professionals to ensure you comply with local laws before removal.

Do Big Brown Bats Hibernate?

Yes. They begin hibernation in late fall and emerge in early spring. They often roost in places that stay above freezing and remain undisturbed.

How Do Big Brown Bats Benefit The Ecosystem?

They help keep insect numbers down by feeding on beetles, moths, and other pests. This natural control helps reduce the need for pesticides and supports agricultural health.