As its name implies, this species has large ears that are over an inch long. The genus name Corynorhinus means "club-nosed." Similar to the Townsend's big-eared bat, this species has two lumps on either side of its nose. Rafinesque's big eared bat is a medium-sized bat with a length of about 7.5–10 cm (3.0–3.9 in) and a wingspan of 25–30 cm (10–12 in). These bats range in mass from 6–13 g (0.21–0.46 oz). The bat is gray on the dorsal side and white on the underside. The ears and face are a pinkish-brown color while the forearm and wing membrane is dark brown.
Some sources report maximum lifespan as 10 years, although robust data are lacking. More research has been done on the closely related Townsend's big-eared bat and estimates for this species' lifespan range from 16 up to 30 years in the wild.
While uncommon throughout its range, this species is found in a variety of habitats from coastal plains, riparian areas, to mountainous areas like the Great Smoky Mountains National Park. In all cases, these bats are associated with large swathes of relatively mature forest.
Rafinesque's big-eared bats, like all bats in the southeastern United States, are insectivorous, nocturnal, and locate food primarily by echolocation. They consume a wide range of insects, including mosquitoes, beetles, and flies, although moths make up 90% of the diet. Insects can be caught by gleaning (e.g., from foliage or cave walls) or on the wing (i.e., aerial hawking).
Due to seasonality, geographical location, and frequent roost-switching, C. rafinesquii can be found in a variety of locations. Tree roosts may be in living or dead trees but are usually quite large (one study reported average diameter at breast height of tree roosts to be 79 cm with a height of 18.5m). Rafinesque's big-eared bats can also be found in abandoned buildings, under bridges, in wells, and in caves.
While listed as least concern by the International Union for the Conservation of Nature (previously listed as vulnerable), Rafinesque's big-eared bats are listed as a Candidate II Species of Concern by the U.S. Fish and Wildlife Service. Additionally, it is listed as threatened by state agencies throughout most of its range.
White nose syndrome is a serious disease caused by a fungal pathogen that has devastated several species of bats in the eastern United States. Unlike some other species of bats with which it shares its range, the Rafinesque's big-eared bat does not appear to be affected by the disease. Hypothesized reasons include use of hibernacula that may not provide optimal growing conditions for the causal agent (the fungus Pseudogymnoascus destructans), relatively frequent arousals from torpor, and/or the usage of shallow bouts of torpor by this species.
The range of Corynorhinus rafinesquii extends from the southern parts of Indiana, Illinois, and Ohio to the southeastern United States. They are found from the eastern part of Texas to North Carolina. They are most common in the Coastal Plain.
Biogeographic Regions: nearctic (Native )
Corynorhinus rafinesquii is a medium size bat with rabbit-like ears. Their ears are about an inch and a half long. They are able to curl the ears backwards over the shoulders. Young bats have gray fur, but they acquire their adult fur three months after birth. The adult color of their fur is grayish brown on top and whitish beneath. Each hair in the stomach has a dark brown base and white tips. The hairs in the long toe extend past the claws. Rafinesque’s big-eared bats weigh between 7-13 g. Adult females are heavier than the adult males. The average weight for females is 9.1 grams and the average weight for males is 8.1 grams. Adult bats are only four inches long but they have a wingspan of eleven inches. Rafinesque’s big-eared bats have a prominent nose. Two large facial glands protrude on the side of its snout.
Range mass: 7 to 13 g.
Average wingspan: 28 mm.
Other Physical Features: endothermic ; heterothermic ; bilateral symmetry
Sexual Dimorphism: female larger
Rafinesque’s big-eared bats roost in cave entrances, hollow trees, crevices behind bark, and dry leaves in the forest. They also live in abandoned buildings and under bridges and prefer to roost in partially lighted areas.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: forest
Other Habitat Features: caves
Rafinesque’s big-eared bats, like most other bats, feed at night. They use echolocation to find their food. Their diet includes mosquitoes, beetles, and flies. However, moths make up 90% of the bat’s diet.
Animal Foods: insects
Primary Diet: carnivore (Insectivore )
Rafinesque's big-eared bats help control the insect population.
Some of their predators are snakes, raccoons, opossums, and cats.
Anti-predator Adaptations: cryptic
Perception Channels: tactile ; chemical
The average lifespan for the rafinesque's big-eared bat is ten years in the wild for males and females.
Status: wild: 10 years.
Rafinesque’s big-eared bats mate in the fall and the females give birth in the summer. The exact gestation period is unknown. In maternity colonies, the females give birth to a single pup in late May and early June. The maternity colonies are usually located in caves or abandoned buildings. The “nursery colonies” are comprised of between 30 to 200 females. Pregnant females segregate from males and non-reproductive females during the spring and summer to rear their young.
Range number of offspring: 1 to 1.
Range weaning age: 21 (low) days.
Average weaning age: 21 days.
Range time to independence: 3 (low) weeks.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous ; sperm-storing
These bats are born naked but they grow gray fur days after birth. The pups are able to fly in three weeks after birth and reach adult size in about a month. Also, the pups molt to their adult fur three months after birth. Females nurse the young in the nursery colony until they reach independence.
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female)
Rafinesque’s big-eared bats have been threatened since 1977 because of loss of roosting areas.
Temperate North American bats are now threatened by a fungal disease called “white-nose syndrome.” This disease has devastated eastern North American bat populations at hibernation sites since 2007. The fungus, Geomyces destructans, grows best in cold, humid conditions that are typical of many bat hibernacula. The fungus grows on, and in some cases invades, the bodies of hibernating bats and seems to result in disturbance from hibernation, causing a debilitating loss of important metabolic resources and mass deaths. Mortality rates at some hibernation sites have been as high as 90%. While there are currently no reports of Corynorhinus rafinesquii mortalities as a result of white-nose syndrome, the disease continues to expand its range in North America.
US Federal List: threatened
CITES: no special status
IUCN Red List of Threatened Species: least concern
There are no adverse effects of Rafinesque's big-eared bats on humans.
Rafinesque's big-eared bats feed on insects that can be harmful to agriculture.
Positive Impacts: controls pest population
Rafinesque’s big-eared bats are one of the least known bats in the southeastern United States. Corynorhinus rafinesquii was previously known as Plecotus rafinesquii. Southeastern-big eared bat, eastern big-eared bat, eastern lump-nosed bat, and eastern long-eared bat are other common names for Rafinesque’s big-eared bat.