Wildlife on the Brink: Indiana Bat

SCIENTIFIC NAME: Myotis sodalis

STATUS: Endangered

HABITAT: Hardwood riparian and floodplain forests in summer; limestone caves in winter

LIFE HISTORY: Hibernate November through March; will migrate up to 300 miles to summer foraging grounds. Individuals return to same cave annually. Cave populations may exceed 100,000 bats.

THREATS: Loss of suitable caves for hibernation due to development and other human disturbances; possible risk due to pesticides

FORMER RANGE: Entire eastern U.S.

CURRENT POPULATION: 350,000-500,000

This little brown bat weighs about as much as a door key, but it's a mighty insect killer. A single colony of Indiana bats can consume a thousand bugs a night, including pest insects like alfalfa weevils and gypsy moths.

Roughly 350,000 Indiana bats are still in existence—87 percent of them hibernate in only seven limestone caves, clustering in tight masses of thousands of bats. Over the past 25 years, the bat's numbers have declined more than 50 percent—disturbance during hibernation by vandals and spelunkers and possibly poisoning by insecticides seem to be the causes. Forest clearing could also be affecting the bat's summer habitat.

The Indiana bat was listed as endangered in 1967.

Photo: Indiana bat © USFWS