Myotis velifercave myotis

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Geographic Range

The cave myotis is found in the south eastern tip of California, throughout the southern 2/3 of Arizona, New Mexico, and throughout all but the eastern 1/4 of Texas. The species is also found in the western half of Oklahoma and reaches barely into Kansas (Whitaker, Jr. 1980)

Within Texas there is seasonal distribution seen in this species of bat: during the summer months, these bats are found in the High Plains, Rolling Plains, Trans-Pecos, Edwards Plateau, and South Texas Plains; during the winter, the species is found in the central and north central portions of the state (Schmidly, 1991).

Habitat

These are cave dwelling bats, usually roosting in large numbers. Furthermore, they will also take the opportunity to roost in a number of other areas, including crevices in rocks/walls, in old buildings, and also under bridges (Twente, 1955).

Physical Description

These bats are relatively large. The individuals in populations from the eastern part of the range have sepia colored fur with paler undersides, while individuals from western populations are almost black. Males are usually slightly smaller than females (Whitaker, Jr. 1980, Hill and Smith 1984).

  • Range mass
    7 to 14 g
    0.25 to 0.49 oz
  • Average mass
    8 g
    0.28 oz
  • Average basal metabolic rate
    0.04 W
    AnAge

Reproduction

Females usually give birth to one young each year, usually around mid-April and May. The nursery colony will break up when the adult females abandon their young at the time of weaning. They will return to the males or live in isolation until the next breeding (Hill and Smith 1984).

The pups are kept in nursery colonies with other newborns, where they are nursed and protected by adult females of the colony. These nurseries can become quite large. The young will fly when they are five weeks old (Kunz, 1995).

  • Range number of offspring
    1 to 1
  • Average number of offspring
    1
    AnAge
  • Range gestation period
    60 to 70 days
  • Average weaning age
    43 days
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    365 days
    AnAge
  • Average age at sexual or reproductive maturity (male)
    Sex: male
    365 days
    AnAge

Lifespan/Longevity

  • Average lifespan
    Status: captivity
    11.3 years
    AnAge

Behavior

These bats are colonial, meaning they roost in large groups, most probably in caves. Cave myotises will hibernate in caves, using their fat reserves which are accumulated throughout the year for nutrition. The clustering behavior most probably helps the bats to stabilize their body temperature, allowing the bats to survive the period of torpidity (Schmidly, 1991).

The bats will usually appear from their roosts after sunset. They forage for insects during the night hours, and have been seen gathering at pools of water in order to drink. Flight patterns that have been observed for this species indicate erratic flight maneuvers making these bats somewhat easy to identify (Fenton, 1992).

This species sometimes form colonies with as many as 20,000 inhabitats in Kansas populations. In all but the Kansas populations, this species is migrates between summer and roosting caves. (Whitaker, Jr. 1980)

Communication and Perception

Food Habits

These bats are insectivorous, mainly feeding on moths. However, they will feed on anything that is available when they emerge from their roosts, including beetles, weevils, and other such insects. As a result of their large size, these bats may be able to forage further away from their roosts than other Myotis bats, thus allowing them to exploit new areas (Kunz, 1974).

Economic Importance for Humans: Positive

These bats are invaluable to us in that they help to control the population of flying insects, which frequently harm crop outputs in all parts of the world (Fenton, 1992).

Economic Importance for Humans: Negative

As with most bat species, these bats run the risk of carrying diseases such as rabies. Though there are very few reported cases of rabies in these bats, it usually is best to take precautions against this disease (Fenton, 1992).

Conservation Status

No special status at the present. They are fairly well distributed (Schmidly, 1991).

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 Myotis velifer 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

There are two subspecies of this bat that are found primarily in Texas. There is not much research on whether the two subspecies cohabitate, though (Hill, 1984).

Contributors

Anisa Ismail (author), Southwestern University, Stephanie Fabritius (editor), Southwestern University.

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

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.

chaparral

Found in coastal areas between 30 and 40 degrees latitude, in areas with a Mediterranean climate. Vegetation is dominated by stands of dense, spiny shrubs with tough (hard or waxy) evergreen leaves. May be maintained by periodic fire. In South America it includes the scrub ecotone between forest and paramo.

chemical

uses smells or other chemicals to communicate

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.

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.

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

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

viviparous

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

References

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/.

Fenton, M. 1992. Bats. Hong Kong:

Hill, J., J. Smith. 1984. Bats: A Natural History. Austin:

Kunz, T. 1995. Changes in milk composition during lactation in three species of insectivorous bats.. Jounral of Comparative Physiology, 164: 543-551.

Kunz, T. 1974. Feeding Ecology of a Temperate Insectivorous Bat (Mytotis Velifer). Ecology, 55: 693-711.

Kunz, T., E. Studier. 1995. Accretion of nitrogen and minerals in suckling bats, Myotis velifer and Tadarida brasiliensis.. Journal of Mammalogy, 76: 32-42.

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.

Schmidly, D. 1991. The Bats of Texas. Houston:

Twente, J. 1955. Some Aspects of Habitat Selection and Other Behavior of Cavern-Dwelling Bats. Ecology, 36: 706-732.

Whitaker, Jr., J. 1980. The Audubon Society Field Guide to North American Mammals. New York: Alfred A. Knopf.