Corynorhinus rafinesquiiRafinesque's big-eared bat

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Geographic Range

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. (Handley, 1955)

Habitat

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. (Barbour and Davis, 1969; Handley, 1955)

  • Other Habitat Features
  • caves

Physical Description

Corynorhinus rafinesquii is a medium size bat with rabbit-like ears. Their ears are about 1.5 inches 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. (Barbour and Davis, 1969; Bat Conservation International, 1999; Jones, 1977)

  • Sexual Dimorphism
  • female larger
  • Range mass
    7 to 13 g
    0.25 to 0.46 oz
  • Average wingspan
    28 cm
    11.02 in

Reproduction

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. (Handley, 1955; Jones, 1977; Wimsatt, 1970)

  • 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

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. (Handley, 1955)

  • Parental Investment
  • altricial
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female

Lifespan/Longevity

The average lifespan for the rafinesque's big-eared bat is ten years in the wild for males and females. (Jones, 1977)

  • Average lifespan
    Status: wild
    10 years

Behavior

Corynorhinus rafinesquii roosts in caves, mines, and hollow trees. They also roost in man-made structures such as abandoned buildings, wells, and bridges. Rafinesque’s big-eared bats are capable of immediate flight when disturbed. However, they are susceptible to predators when they are hibernating because it takes them several minutes to wake up. They hibernate during the winter. During hibernation, the males and the females sleep in the same place, unlike during the summer when they roost in separate areas. When these bats hibernate, they coil their ears in front of their face and fold their wings. During the summer, they are capable of immediate flight at night. They can fly swiftly but they can also hover. (Barbour and Davis, 1969; Jones, 1977; Wimsatt, 1970)

Communication and Perception

Food Habits

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. (Defenders of Wildlife, 1999; Jones, 1977)

  • Animal Foods
  • insects

Predation

Some of their predators are snakes, raccoons, opossums, and cats. (Jones, 1977)

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

Rafinesque's big-eared bats help control the insect population.

Economic Importance for Humans: Positive

Rafinesque's big-eared bats feed on insects that can be harmful to agriculture.

  • Positive Impacts
  • controls pest population

Economic Importance for Humans: Negative

There are no adverse effects of Rafinesque's big-eared bats on humans.

Conservation Status

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. (Cryan, 2010; National Park Service, Wildlife Health Center, 2010)

Other Comments

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. (Jones, 1977)

Contributors

Eduardo Reyes (author), University of Michigan-Ann Arbor, Bret Weinstein (editor), University of Michigan-Ann Arbor.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

colonial

used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

insectivore

An animal that eats mainly insects or spiders.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

sperm-storing

mature spermatozoa are stored by females following copulation. Male sperm storage also occurs, as sperm are retained in the male epididymes (in mammals) for a period that can, in some cases, extend over several weeks or more, but here we use the term to refer only to sperm storage by females.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

threatened

The term is used in the 1994 IUCN Red List of Threatened Animals to refer collectively to species categorized as Endangered (E), Vulnerable (V), Rare (R), Indeterminate (I), or Insufficiently Known (K) and in the 1996 IUCN Red List of Threatened Animals to refer collectively to species categorized as Critically Endangered (CR), Endangered (EN), or Vulnerable (VU).

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

Barbour, R., W. Davis. 1969. Bats in America. Kentucky: Lexington Press Kentucky.

Bat Conservation International, 1999. "Texas Parks & Wildlife" (On-line). Accessed October 8, 2001 at http://www.tpwd.state.tx.us/nature/wild/mammals/bats/species/rafinesque.htm.

Cryan, P. 2010. "White-nose syndrome threatens the survival of hibernating bats in North America" (On-line). U.S. Geological Survey, Fort Collins Science Center. Accessed September 16, 2010 at http://www.fort.usgs.gov/WNS/.

Defenders of Wildlife, 1999. "Defenders of Wildlife" (On-line). Accessed October 9, 2001 at http://www.defenders.org/wildlife/bats/.

Handley, C. 1955. A new Pleistocene bat (*Corynorhinus*) from Mexico. Washington: Journal of Washington of Academy of Sciences.

Jones, C. 1977. Mammalian Species 69:1-4. New York: American Society of Mammalogists.

National Park Service, Wildlife Health Center, 2010. "White-nose syndrome" (On-line). National Park Service, Wildlife Health. Accessed September 16, 2010 at http://www.nature.nps.gov/biology/wildlifehealth/White_Nose_Syndrome.cfm.

Wimsatt, W. 1970. Biology of Bats Vol. II. New York: Academic Press.