Big Brown Bat

Eptesicus fuscus

Copyright, Roger Barbour

Big Brown Bats are one of the most common bats in Northern Virginia, as well as the largest. Their bodies are about five inches long, not counting the tail, and they have a wingspan of up to 13 inches.

Big Brown Bats have brown fur above, and paler fur below. Their wings are black and have no fur. They only weigh about half of an ounce.

Big Brown Bats can be found all over. They live in forests, cities, parks, and farms.

Copyright, Bat Conservation International

Copyright, James F. Parnell

Copyright, Bull Snook

Big Brown Bats roost in hollow trees, buildings, caves, storm sewers, and under bridges. In Winter, they hibernate, often in buildings and usually alone.

Big Brown Bats breed from November to March. After breeding season, they form maternity colonies (mothers and babies) of up to 600 bats. Female bats give birth to one or two young (usually twins). Young bats can fly in three to four weeks.

Mothers communicate to their babies with high-pitched squeaks. Males do not participate in raising young.

Big Brown Bats often live over 10 years.

Copyright, Patrick Coin, used with permission

Copyright, Bat Conservation International

Big Brown Bats eat insects, especially flying beetles. They also eat moths, wasps, flies, stinkbugs, dragonflies, flying ants, mosquitos, lacewings, planthoppers, and leafhoppers.

These bats catch their prey while flying. They do not see their prey. To hunt, they use echolocation. This means they send out high-frequency sounds (humans can't hear them) which bounce of objects, big and small. Then they can listen to the echoes and tell where things are, what size they are, and how they're moving.

Big Brown Bats catch insects in their wings.

Copyright, J. Scott Altenbach

Big Brown Bats can fly 40 miles per hour. They have few predators, but if they are caught they are eaten by owls, raccoons, snakes, and cats.

Additional Media

Description
Type
Credit

Big Brown Bat Sound #1

Sound
Unknown
Sound #2
Sound
Unkown
Sound USGS, Western Ecological Research Center
Animation of Bat Echolocation Link Kentucky Bat Working Group

Relationships in Nature:

PREY
PREDATORS
SHELTER
OTHER

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Barred Owl

Black Willow

Pileated Woodpecker SP

Pennsylvania Firefly

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Red Maple

Human SP

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Black Oak

Luna Moth

Great Horned Owl

American Sycamore

European Gypsy Moth

Red-tailed Hawk

American Beech

Asian Tiger Mosquito

Sharp-shinned Hawk

Eastern White Pine

Eastern Bloodsucking Conenose

Silver Maple

Green Darner

Loblolly Pine

Eastern Yellow Jacket

Black Carpenter Ant

Eastern Dobsonfly

Eastern Tent Caterpillar Moth

Blue Bottle Fly

Dogday Harvestfly

Chinese Mantid

Cicada Killer

Fungus Gnat

Fiery Searcher

Clouded Sulphur

Northern Caddis Fly

Relationship to Humans:

Many people are afraid of bats and have no reason to be. Big Brown Bats rarely come into contact with humans. They do often roost in houses, but most people don't know they're there. Big Brown Bats are also feared for rabies, but they rarely get rabies. If a bat does have rabies, it does not attack like other animals, but stays still. Bats will bite, so you should not touch them.

Big Brown Bats, like all bats, are a great help to people. They eat huge amounts of insects, many of which are pests, like mosquitos.

SCIENTIFIC CLASSIFICATION

KINGDOM
Animal
PHYLUM
Chordate
CLASS
Mammal
ORDER
Chiroptera
FAMILY
Vespertilionidae
GENUS
Eptesicus
SPECIES
Eptesicus fuscus

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