Wingspan: 8–10 in.
Total length: 3–3.5 in.
Weight: 0.14–0.28 oz
Color: Easily identified by its tricolored fur (black at the base, followed by a band of lighter brown, and dark tips) and the juxtaposition of its black wing membrane surrounding a reddish orange forearm. Can often be identified when hibernating by its distinctive orange forearm.
Other: About the size of a matchbook.
Roosting behavior: One of the first bats to enter hibernation, typically in September or October, and one of the last to emerge in the spring.
Makes short annual migrations between winter hibernation and summer nursery sites. Travels an average of 31 miles or less and no more than 50 miles.
Spends 6 to 9 months per year hibernating in caves or mines, mostly when temperatures are 46 to 55 °F.
May return to the same hibernation site every winter.
During the summer, the sexes live separately; males are often solitary while females form small maternity colonies of 35 or fewer individuals in buildings, tree cavities, and rock crevices.