Rafinesque's Big-Eared Bat

Kentucky Status:  Special Concern

Description:  A medium-sized bat, approximately 4 inches in length with a wingspread of about 11 inches. Among Kentucky bats, only the Virginia big-eared bat (Corynorhinus townsendii virginianus) also has large, conspicuous ears; several characters separate the two. The Rafinesque’s big-eared bat has grayish-brown fur on the upperparts, a whitish belly, and long toe hairs that extend noticeably beyond the tips of the toes. The Virginia big-eared bat has medium brown upperparts, a buffy belly color, and very short toe hairs. Both species of big-eared bats have two large lumps (glands) on the upper surface of the snout, accounting for the alternative name, “lump-nosed” bat.

Range:  Rafinesque’s big-eared bats are found locally through Southeastern United States from Virginia, southern West Virginia, Ohio, Indiana, and Illinois, south through the lower Mississippi Valley through southeastern Missouri, central Arkansas, southeastern Oklahoma and eastern Texas to the Gulf and Atlantic coasts.

Distribution in Kentucky:  See map

Kentucky Occurrence Summary: This species is a year-round resident in Kentucky, probably moving only short distances between summer and winter roosting sites. The species occurs locally across the state, but is most common along the western edge of the Cumberland Plateau and in the Mammoth Cave region.

Habitat and Life History: Rafinesque’s big-eared bats use a great variety of roost sites. In Kentucky, most individuals hibernate in caves, although some have been found using old mines and protected rock shelters along clifflines. Many are found hibernating singly, but clusters of 100 or more individuals have been observed. From spring through fall, the species is most often found in sandstone rock shelters along clifflines and in small caves, but abandoned buildings are frequently used in some areas. In addition, there are occurrences of roosts under bridges and even in a cistern, and these bats likely use large, hollow trees as summer roosts, especially in far western Kentucky. Maternity colonies consist of from a few to several dozen females and are present from May through August or September. The pups are typically born in late May and early June, and they are on the wing by mid-July. Male bats may roost singly or in small clusters at different sites from the females and young. Rafinesque’s big-eared bats are thought to use forest and forest edge areas for foraging, preying mostly on moths, which they frequently eat at roost sites. A collection of moth wings on the ground often indicates the species’ use of a sheltered place as a roost site. 

Threats:  One primary threat to Rafinesque’s big-eared bats is the loss and degradation of mature bottomland hardwood forests due to agricultural conversion and urban expansion. Habitat alteration has greatly reduced the amount of suitable summer roosting and foraging habitat for the species. Clearing of mature upland forests is also a threat. Since the species uses caves and rockshelters as hibernacula or maternity sites, it is also subject to human disturbance. Hibernating bats can be awakened by excessive human visitation, causing the bats to use up important fat reserves. Disturbance to maternity sites can cause the bats to move to a less suitable site. And as of 2016, no Rafinesque’s big-eared bats have been documented with diagnostic signs of white-nose syndrome, though they have tested positive for the fungus that causes it.