The big brown bat plays a big role in nature. These nighttime flyers help keep insect populations in check, but when they decide your attic or walls make a good roost, things can get messy. At Western Exterminator, we respect bats for the vital work they do outdoors. Our job is to help guide them back there, using humane methods that protect both the bats and your home. See our bat control page for more information about our services.
The large brown bat, Eptesicus fuscus, is built for survival. Solid and sturdy, it can thrive in environments that challenge many other bat species. Weighing from about 0.4 to 0.9 ounces and stretching four to five inches long, it’s a compact powerhouse with a wingspan reaching up to 13 inches.
The big brown bat's size gives it strength in flight and resilience in colder weather. These bats are nocturnal, using precise echolocation to hunt down flying insects long after the sun sets.
If you spot a bat with glossy brown fur and broad wings darting around your porch lights, chances are it’s a big brown bat. They have a heavier build and wider nose than many other bats, giving them an unmistakable look once you know what to watch for.
Indoors, the clues are more subtle: soft scratching sounds at dusk, droppings near entry points, or a musty odor in the attic. It’s best not to try to catch or move a bat on your own. Our trained technicians can identify the species and handle the situation with care.
The big brown bat’s habitat can range from forest trees to barns and city rooftops. During the day, they tuck themselves into tight, dark spaces like under loose bark, behind shutters, or inside attics. In the colder months, they’ll hibernate in basements, caves, or mines where temperatures stay steady.
Their knack for finding warm, secure roosts is impressive, but it’s also what brings them into conflict with people. Once they’ve chosen a spot, they tend to return to it year after year.
From the Pacific Northwest to Florida, big brown bats are found just about everywhere in the continental U.S. They’ve adapted to nearly every climate, making them one of the country’s most widespread bat species. Whether you live downtown or in a rural area, it’s not unusual to have them flying nearby on summer evenings.
These bats are social and often gather in small colonies during their maternity season, typically in the early summer months. The big brown bat's diet consists mainly of beetles and moths, which makes them great natural pest control outdoors.
However, when they move into a home, problems can follow. Their droppings, called guano, can build up and cause odors while damaging insulation and other materials. Guano can also support a fungus linked to histoplasmosis, a respiratory illness that may develop if airborne spores are inhaled.
Big brown bats can also carry rabies, although cases are uncommon. Because bites can be very small and hard to notice, it’s best not to touch or handle a bat, even if it seems harmless. In rare cases, bats have also been associated with diseases such as St. Louis encephalitis, which spreads indirectly through insects. While big brown bats rarely pose a direct threat to people, avoiding contact helps protect both your health and theirs.
Because bats are protected wildlife, removal must always be humane and carefully timed. We use professional methods like funneling and exclusion to relocate bats.
In funneling, a mesh net is placed over their main exit points so bats can fly out but can’t fly back in. After a couple of weeks, once all bats have left, exclusion begins. This step involves sealing up those entry points using materials like caulk or copper gauze. Together, these techniques help ensure bats are out for good while causing minimal harm.
The big brown bat is a common bat species known for its sturdy build and wide wingspan. It’s an important part of the ecosystem because it helps control insect populations.
They live in a variety of habitats, from forests and barns to attics and city buildings. During winter, they hibernate in protected spaces like caves or basements.
Their diet mainly consists of beetles, moths, and other night-flying insects. They’re skilled hunters, using echolocation to find their prey in the dark.
The big brown bat’s life cycle - including hibernation in attics and human dwellings during the winter - can bring them into close proximity to humans. But they’re not aggressive and usually avoid people.
They have glossy brown fur, darker wings, and a broad nose that gives them a heavier appearance than smaller bat species. Their slow, steady flight also makes them easy to distinguish from other species.
Even a few bats can quickly multiply into a colony. While a lone big brown bat in the attic might seem harmless, a group can quickly infest the space, leaving behind droppings, noise, and damage in just a short time. If you’re hearing scratching, rustling, or squeaking at dusk, it could mean more than one.
Our technicians can inspect your property for free to determine if you’re dealing with an isolated visitor or a full-blown bat infestation, and help guide you toward a long-term solution.
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