All Idaho bats feed on insects, two are obligate tree roosters and one appears to be restricted to cracks in desert canyons containing cliffs. The remaining species are found in multiple roost situations. Three distinct characteristics that separate Idaho bats from other Idaho mammals include the ability to fly, echolocate, and the rotation of the upper leg bones. Rotation places the knee joints on the opposite side of the leg. The leg position aids wing support and permits bats to hang upside down, a condition enhancing rapid flight from a resting state and enabling watchful vigilance if they are not hibernating.
Some bats hibernate in Idaho during winter whereas others migrate to warmers regions.
The family Vespertilionidae contains more bat species than any other group. Vespertilionids demonstrate a diversity of roosting sites including buildings, especially attic areas, caves, mines, fractures in rock and hollowed locations or foliage roosts in trees. Fewer than 400 specimens of Idaho bats have been professionally prepared and deposited in natural history museums in the United States. Consequently, the distribution of each of the species is very poorly known. Closures are being mandated as a result of unstable and deteriorated conditions that endanger unsuspecting humans who do not understand their interest in exploring an old mine may lead to a tragic outcome.