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Emballonura monticolalesser sheath-tailed bat

By Kelly Kraemer

Geographic Range

Lesser sheath-tailed bats can be found in the Malay Peninsula and the surrounding areas, including some offshore islands. ("Lesser sheath-tailed bat", 2009; Baker, 2009; Bates, et al., 2008)

Habitat

Lesser sheath-tailed bats are often found in areas of lowland forest and subtropical/tropical moist areas, primarily up to 1800 m. This species roosts in caves and cave entrances, rock crevices, large tree holes, and forests. They can be found in smaller numbers hanging under tables and buttresses in lowland forest Malaysia, hanging rock in tropical lowland forests and manmade caves in Thailand. ("Lesser sheath-tailed bat", 2009; Baker, 2009; Bates, et al., 2008)

  • Other Habitat Features
  • caves
  • Range elevation
    1800 (high) m
    5905.51 (high) ft

Physical Description

Lesser sheath-tailed bats have very smooth and shiny fur that ranges from dark to reddish brown. Their underside is brown and wings are black. They have triangular shaped ears, large eyes and a pointed, simple nose that has no noseleaf. A short tail protrudes from the membrane between the legs, and, when the legs are stretched, the tail is retracted in a membrane (uropatagium) and unseen. When the wings of lesser sheath-tailed bats are relaxed, they have an extra fold that distinguishes them from other bat families. This species can fly straight and fast due to the shape of their bodies, allowing them to follow gaps formed by streams or paths in the forest. The forearm is generally 43 to 45 mm in length. The dental formula is (i 2/3, c 1/1, pm 2/2, m 3/3) x 2 = 34. g. Emballonura are the only genera in the family to have two pairs of upper incisors. A "W" pattern of cusps and ridges is also found in their molars. ("Lesser sheath-tailed bat", 2009; Baker, 2009; Nowak, 1999; Pottie, et al., 2005)

  • Range mass
    4 to 5 g
    0.14 to 0.18 oz
  • Range length
    40 to 45 mm
    1.57 to 1.77 in
  • Range wingspan
    26.1 to 26.58 cm
    10.28 to 10.46 in

Reproduction

Lesser sheath-tailed bats are believed to be polygynous, though little information is available regarding the mating systems of this species. (Voigt, 2004)

Lesser sheath-tailed bats have two breeding seasons per year, the first in February through March and the second in October through November. During each birth period, females give birth to a single offspring. The pup weighs about a quarter of the mother's weight. ("Lesser sheath-tailed bat", 2009; Voigt, 2004)

  • Breeding interval
    Lesser sheath-tailed bats have two breeding seasons per year
  • Breeding season
    Mating of lesser sheath-tailed bats occurs in February-March and in October-November
  • Average number of offspring
    1
  • Average time to independence
    1 years
  • Average age at sexual or reproductive maturity (female)
    1 years
  • Average age at sexual or reproductive maturity (male)
    1 years

Female lesser sheath-tailed bats scoop their pups to their body with their wings as soon as a pup is born, preventing it from falling. The pup clings to its mother's body while she forages until the pup becomes too heavy to carry. Soon after weaning, usually within a year, the pup becomes a mature adult. ("Lesser sheath-tailed bat", 2009; "Emballonura monticola", 2003)

  • Parental Investment
  • female parental care
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female
  • pre-independence
    • provisioning
      • female
    • protecting
      • female

Lifespan/Longevity

Little information is available regarding the lifespan of lesser sheath-tailed bats.

Behavior

Daytime roosts of lesser sheath-tailed bats usually range from 2 to 20 individuals, though some larger colonies have been found in caves ranging from 100 to 150 bats. ("Emballonura monticola", 2003)

Home Range

Little information is available regarding the home range of lesser sheath-tailed bats.

Communication and Perception

Lesser sheath-tailed bats have a very distinct echolocation call lasting 6 to 8 milliseconds. Each call consists of a short sweep up in the frequency range, then a steady constant frequency staying between 48 and 51 kHz. The call finishes with a sweep down through its frequency range. Emballonura monticola studied in Singapore were recorded as having a maximum frequency of 49.3 kHz and a minimum frequency of 46.0 kHz. ("Lesser sheath-tailed bat", 2009; Pottie, et al., 2005)

Food Habits

Lesser sheath-tailed bats primarily hunt insects in dense forests. They have also been observed during the day in dense shade foraging for insects. This species has also occasionally been observed eating fruit. ("Emballonura monticola", 2003; Nowak, 1999)

  • Animal Foods
  • insects
  • Plant Foods
  • fruit

Predation

Little information is available regarding predators of lesser sheath-tailed bats.

Ecosystem Roles

As insectivores, lesser sheath-tailed bats may regulate insect populations. Because lesser sheath-tailed bats occasionally eat fruit, they may contribute to seed dispersal.

  • Ecosystem Impact
  • disperses seeds

Economic Importance for Humans: Positive

Many bats, including lesser sheath-tailed bats, contribute to the control of insect pests on crops. ("Lesser sheath-tailed bat", 2009)

  • Positive Impacts
  • controls pest population

Economic Importance for Humans: Negative

No information known.

Conservation Status

Lesser sheath-tailed bats are declining in population but are still considered of Least Concern on the IUCN Red List because of their location. Most members of this species are currently located within protected areas, and populations are decreasing at a rate that ranks them as non-threatened. Increased deforestation from illegal logging and forest fires as well as destruction of caves due to limestone extraction are of increasing concern. Both scientific groups and retailers are promoting educational programs to raise awareness (Bates, et al., 2008)

Other Comments

Because of continued demand for palm oil, which is used in margarine, lipstick, and detergent, deforestation is continuing in prime habitat of lesser sheath-tailed bats. Malaysia and Indonesia together contribute about 88% of the world's palm oil. Large retailers, including Migros, Switzerland's largest retail chain, have expressed their concern for the destruction of these habitats due to palm oil production. Migros has recently ensured all of their products made of palm oil will not contribute to deforestation. ("Lesser sheath-tailed bat", 2009; Bates, et al., 2008; "Swiss Palm Oil Products May Help Save Indonesian Forests", 2001)

Contributors

Kelly Kraemer (author), Northern Michigan University, John Bruggink (editor), Northern Michigan University, Gail McCormick (editor), Animal Diversity Web Staff.

Glossary

acoustic

uses sound to communicate

arboreal

Referring to an animal that lives in trees; tree-climbing.

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.

echolocation

The process by which an animal locates itself with respect to other animals and objects by emitting sound waves and sensing the pattern of the reflected sound waves.

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.

female parental care

parental care is carried out by females

forest

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

insectivore

An animal that eats mainly insects or spiders.

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

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

World Map

polygynous

having more than one female as a mate at one time

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

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.

tactile

uses touch to communicate

terrestrial

Living on the ground.

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

ultrasound

uses sound above the range of human hearing for either navigation or communication or both

References

Gale Group. 2003. Emballonura monticola. Pp. 362-363 in D Kleiman, V Geist, M McDade, eds. Grzimek's Animal Life Encyclopedia, Vol. 13, Second Edition. Farmington Hills, MI: Thomson Gale.

2009. "Lesser sheath-tailed bat" (On-line). ARKIVE.org. Accessed February 12, 2009 at www.arkive.org/Lesser-sheath-tailed-bat/emballonula-monticola/description.html.

EuropaWorld. 2001. "Swiss Palm Oil Products May Help Save Indonesian Forests" (On-line). Europaworld.org. Accessed March 12, 2009 at http://www.europaworld.org/issue66/swisspalm25102.htm.

Baker, N. 2009. "Lesser Sheath-tailed Bat" (On-line). EcologyAsia.com. Accessed February 12, 2009 at www.ecologyasia.com/verts/bats/Lesser_sheath-tailed_bat.htm.

Bates, P., C. Francis, T. Kingston. 2008. "IUCNresource.org" (On-line). The IUCN Red List of Threatened Species. Accessed February 08, 2009 at www.iucnredlist.org/details/7674.

Nowak, R. 1999. Emballonura monticola. Pp. 310-311 in Walker's Mammals of the World, Vol. 1, Sixth Edition. Baltimore and London: John Hopkins University Press.

Pottie, S., D. Lane, T. Kingston, B. Lee. 2005. The microchiropteran bat fauna of Singapore. Acta Chiropterologica, 7(2): 237-247. Accessed March 10, 2009 at http://www.mbcru.com/index_files/Pottie%20et%20al.%202005--Acta.pdf.

Voigt, C. 2004. Sac-Winged Bats, Sheath-Tailed Bats, and Ghost Bats (Emballonuridae). Pp. 355-265 in M Hutchins, D Thoney, M McDade, eds. Grzimek's Animal Life Encyclopedia, Vol. Vol. 13, 2nd Edition. Detroit: Gale Virtual Reference Library. Accessed March 10, 2009 at http://find.galegroup.com/gvrl/infomark.do?&contentSet=EBKS&type=retrieve&tabID=T001&prodId=GVRL&docId=CX3406700828&source=gale&userGroupName=lom_nmichu&version=1.0.

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