Little Brown Bat (Myotis lucifugus) and Big Brown Bat (Eptesicus fuscus)

Eight different species of bats can be found in Connecticut, but the most common are the little brown and big brown bats. Big brown bats are wild residents to the Zoo and surrounding area, so take a moment to look up at the night sky while in your backyard. You may see them flying around.


Bodies are covered in fur and are warm blooded. 2 - 7 inches long with wingspan 9 - 16 inches. Wings are made of tiny bones with leathery elastic skin to hold the bones together and to the body. Skin is a web used to scoop up flying insects into the bat’s mouth. Thumbs stick out from the wing and end in a claw good for climbing. Bats are not blind; they use echolocation like SONAR to find targets but fly using eyesight alone.


Near streams or lakes; they hibernate in winter in old mines or caves. Sometimes, during hibernation season, they will wake up and fly around, but they do not eat all winter. Spring, summer and fall, they sleep in the total darkness of a cave during the day and fly out at night to hunt.


Most of the northern United States and Canada, excluding Alaska.


Insectivorous: insects. Approximately 1,200 mosquitoes an hour.

Life Span: 

18 - 20 years in the wild. 

Family Life: 

Female bats give birth to 1 - 2 two pups in the spring. They live together in a nursery colony of thousands of bats. Pups nurse for two weeks; able to fly at three weeks.


Least concern. White-nose Syndrome (a fungus that causes them to use up their fat storage long before winter is over) is threatening local bat populations.