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Molossops temminckiidwarf dog-faced bat

By Gavin Busby

Geographic Range

Occurring exclusively in the neotropical region of the world, Molossops temminckii, or dwarf dog-faced bats, can be found in nearly every country in South America. This New World bat ranges in the north from Colombia and Venezuela to Brazil and Argentina in the south. (Brooks, 2001; Gregorin, et al., 2004; Lopez-Gonzalez, 1998; Male, 2001; Myers and Wetzel, 1984; Silva, 2001; Wilson and Reeder, 2005)

Habitat

Dwarf dog-faced bats have a large variety of habitats spanning many diverse geographical regions. They are primarily found in Amazonian rainforest and semi-deciduous forests, often near the forest edge and among dispersed trees near savannah or grasslands. They can also be found in dry lowland environments. Dwarf dog-faced bats roost in a variety of places, including caves, rock crevices, tree cavities, underneath tree bark, in rotting logs, foliage, and even holes in the ground. They also commonly inhabitant man-made structures, finding their way into attics and open spaces above human living areas. They are frequently found in roofs made of overlapping palm logs. Dwarf dog-faced bats can be found at sea level near the Atlantic ocean to elevations of over 1000 m at the base of the Andes Mountains. (Gregorin, et al., 2004; Guillen-Servent and Ibanez, 2007; Lopez-Gonzalez, 1998)

  • Range elevation
    0 to > 1000 m
    0.00 to ft

Physical Description

Dwarf dog-faced bats are free tailed bats in the family Molossidae, members of which have a bony tail that is lacking a tail sheath. The genus Molossops, or dog-faced bats, is so named for the protruding nature of the snout that is dog-like in appearance. Dwarf dog-faced bats are the smallest in their genus, and may also be the smallest bats in Paraguay with an average length of less than 33 mm. Their skulls are distinctly broad and dorsoventrally (back to front) flattened. They have small eyes, and their ears are not joined at the midline of the skull but rather are well-separated and usually short and erect. Their tragus is short and triangular, while their antitragus is square and broad. Dwarf dog-faced bats have smooth upper lips and a dental formula of - 1/1-2 I, 1-1 C, 1-2/2 P, 3/3 M = 26-30 teeth. Like other Microchiroptera, dwarf dog-faced bats have a relatively short wingspan of .222 m +/- .004 m in males and .221 m +/- .004 m in females. Despite their small size, they are well adapted for flight. A ring of cartilage slides along the vertebrae in the tail by muscle contractions, stretching and retracting the tail membrane, and provides greater maneuverability in flight. Dwarf dog-faced bats have relatively long pelage, with hairs that extend beyond the claws of the toes. The dorsal side varies in color from dark brown, with the base of individual hairs yellowish with black membranes, to sandy brown, with whitish base color and light membranes. Pelage on the ventral side is usually lighter in color. In arid environment, the general color of their pelage is also lighter. Dwarf dog-faced bats exhibit sexual dimorphism, with males about 5% larger and more robust than females. Males also posses a scent gland used to mark members of their colony with a distinctive odor; this gland is typically rudimentary or absent in females. (Lopez-Gonzalez, 1998; McCracken, 2004; Myers and Wetzel, 1984)

  • Sexual Dimorphism
  • male larger
  • Range mass
    female 4.0 g, 4.1 male to female 6.6 g, 7.0 male g
    to oz
  • Range length
    33 (high) mm
    1.30 (high) in
  • Average wingspan
    0.222 m
    0.73 ft

Reproduction

Dwarf dog-faced bats are thought to be polygynous, in which a male mates with more than 1 female during a single breeding season. (McCracken, 2004; Myers and Wetzel, 1984)

The breeding patterns of Dwarf dog-faced bats seem to vary with environment. Breeding begins ranging from July in southeastern Brazil to late August and early September in Paraguay. During pregnancy and lactation, females generally roost in maternity colonies separate from adult males. Females dwarf dog-faced bats give birth to a single offspring each year called a pup, however occasionally twins are born. The gestation period is approximately 2 to 3 months in length and offspring typically weigh 20 to 30% of the parents mass at birth. Weaning usually occurs at 5 to 6 weeks of age. (McCracken, 2004; Myers and Wetzel, 1984)

  • Breeding interval
    Dwarf dog-faced bats breed once per year.
  • Breeding season
    Dwarf dog-faced bats breed in mid to late winter.
  • Average number of offspring
    1
  • Range gestation period
    2 to 3 months
  • Range weaning age
    5 to 6 weeks

Females dwarf dog-faced bats nurse their pups until they are weaned. (McCracken, 2004)

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

Lifespan/Longevity

The lifespan of dwarf dog-faced bats is not known. In general, bats are estimated to live a maximum of 20 to 30 years in extreme cases and, in most species, average 4 to 5 years of life. (Baldwin, 2006)

Behavior

Nocturnal creatures, dwarf dog-faced bats are social animals that commonly forage in large groups, called a colony or cloud, to exploit large patches of insects. They are aerial hawking bats, using echolocation to find prey, which is common in insectivorous bats. They generally fly about 4 m or higher from the ground. Dwarf dog-faced bats tend to roost near food sources to reduce foraging costs. They also use scent markings for recognition of colony members. (Cunha, et al., 2009; Guillen-Servent and Ibanez, 2007; McCracken, 2004; Cunha, et al., 2009; Guillen-Servent and Ibanez, 2007; McCracken, 2004; Cunha, et al., 2009; Guillen-Servent and Ibanez, 2007; McCracken, 2004)

Home Range

Little information is available regarding the home range of dwarf dog-faced bats.

Communication and Perception

The primary method of communication and perception in bats, including dwarf dog-faced bats, is echolocation , which allows bats to hunt and navigate without light. Bats emit a short, high frequency, ultrasonic pulse to help determine the direction, distance, and features of objects in their environment from biaural cues such as arrival time, amplitude, and spectrum of sonar reflections. Bats modify these pulses to change duration, repetition rate, and intensity of calls. Dwarf dog-faced bats have an unusual ability to manipulate their use of echolocation, modifying their pulse emissions to a high degree. The echolocation cycles of bats can be broken down to a few general types of pulses. The first is the search phase, which has a count of 1 pulse per wing beat, and the emission is occasionally broken. The second phase is the approach phase, where the pulse rate increases to 2 pulses per wing beat. This higher frequency allows for more precise information about prey and surrounding area and structures. The next phase is the buzz or terminal phase, which occurs just before the capture of prey and is marked by a short pulse with a high rate of repetition, approximately 14 to 28 pulses. After the buzz phase, there is generally a period of silence, which is thought to occur while bats consume their prey. Dwarf dog-faced bats also use scent marking as a form of communication in order to maintain recognition of their home colony. (Guillen-Servent and Ibanez, 2007; Jakobsen and Surlykke, 2010)

Food Habits

Dwarf dog-faced bats are insectivorous bats that forage in groups to exploit large patches of insects in locations that attract high densities of insects such as near rotten wood or near streetlights. Their diet primarily consists of small beetles in the order Coleoptera as well as swarms of termites, winged ants, and moths. One captured and photographed individual had pollen on its lips from a bat-pollinated flower Bauhinia rufa, which may suggest consumption of pollen. Indeed, other insectivorous bats are expected to expand their diet to include pollen. It is also possible, however, that this bat was foraging for insects that visit flowers. (Cunha, et al., 2009; Drees and Jackman, 1999; Guillen-Servent and Ibanez, 2007)

  • Animal Foods
  • insects

Predation

Predators of dwarf dog-faced bats include owls, falcons, specifically the bat-falcon, and other raptors. Carnivorous bats, and snakes that manage to find a roosting site may also prey on dwarf dog-faced bats. When near humans, they may also be preyed upon by domestic cats. (Baldwin, 2006; Cholewiak, 2003; Guillen-Servent and Ibanez, 2007; Myers, et al., 2008)

Ecosystem Roles

Dwarf dog-faced bats help control some insect populations. They are also hosts to a variety of parasitic organisms, such as members of the family Nycteribiidae, or flies that feed on the blood of bats, and members of the genus Ornithodoros, or neotropical ticks common in bats. (Graciolli, et al., 2006; Nava, et al., 2007)

Commensal/Parasitic Species

Economic Importance for Humans: Positive

Dwarf dog-nosed bats control insect populations, including crop pests. The nitrogen-rich bat guano of the family Molossidae is also harvested commercially for use in fertilizer. (McCracken, 2004)

  • Positive Impacts
  • produces fertilizer
  • controls pest population

Economic Importance for Humans: Negative

Dwarf dog-faced bats are considered pests when they roost in buildings used by humans. A fungus Histoplasma capsulatum can also grow on bat guano when left unchecked, which can release toxic spores. When these spores are inhaled, humans can contract Histoplasmosis, a disease that primarily affects the lungs and can become fatal. Bats also have a notoriously bad reputation for being carriers of the disease rabies. Although the percentage of rabies contraction from bat bites is very low, the ensuing cost of medical treatments can be an economic burden on an individual level. (McCracken, 2004)

Conservation Status

Dwarf dog-faced bats are abundant and are listed as a species of "least concern" on the IUCN Red List. (Wilson and Reeder, 2005)

Other Comments

There are three subspecies of dwarf dog-faced bats: Molossops temminckii sylvia, Molossops temminckii temminckii, and Molossops temminckii griseiventer. (Wilson and Reeder, 2005)

Contributors

Gavin Busby (author), University of Oregon, Stephen Frost (editor), University of Oregon, Gail McCormick (editor), Animal Diversity Web Staff.

Glossary

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

acoustic

uses sound to communicate

agricultural

living in landscapes dominated by human agriculture.

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

causes disease in humans

an animal which directly causes disease in humans. For example, diseases caused by infection of filarial nematodes (elephantiasis and river blindness).

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.

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

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.

scent marks

communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them

scrub forest

scrub forests develop in areas that experience dry seasons.

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.

suburban

living in residential areas on the outskirts of large cities or towns.

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.

tropical

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

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

ultrasound

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

References

Baldwin, M. 2006. "Bats" (On-line). Wildlife Online. Accessed December 05, 2010 at http://www.Wildlifeonline.me.uk/bats.html.

Brooks, D. 2001. "Terrestrial Ecoregions: Chaco" (On-line). World Wildlife fund. Accessed December 05, 2010 at http://www.worldwildlife.org/wildworld/profiles/terrestrial/nt/nt210_full.html.

Cholewiak, D. 2003. "Animal Diversity Web" (On-line). Accessed December 06, 2010 at http://animaldiversity.ummz.umich.edu/site/accounts/information/strigigormes.html.

Cunha, N., E. Fischer, L. Cunha, C. Santos. 2009. Bats of Buraco das Araras Natural Reserve, South Western Brazil. Biota Neotropica, 9/4: 190-195. Accessed November 20, 2010 at http://http://www.scielo.br/pdf/bn/v9n4/v9n4a19.pdf.

Drees, B., J. Jackman. 1999. Field Guide to Texas Insects. Houston, Texas: Gulf Publishing Company. Accessed December 07, 2010 at http://insects.tamu.edu/fieldguide/orders.html.

Graciolli, G., C. Dick, D. Gettinger. 2006. A Faunal Survey of Nycteribiid Flies (Diptera: Nycteribiidae) associated with the bats of Paraguay. Zootaxa, 1220: 35-46. Accessed December 05, 2010 at http://www.nhm.ac.uk/hosted_sites/acarology/saas/saa/abst12/saa12_04.html.

Gregorin, R., B. Lim, W. Pedro, F. Passos, V. Taddei. 2004. Distribution extension of Molossops neglectus (chiroptera, molossidae) into Southeastern Brazil. Mammalia, 68 (2-3): 233-237. Accessed November 08, 2010 at http://zoo.bio.ufpr.br/mamifero/Molossops%20Gregorin%20Lim%20Pedro%20Passos%20Taddei%202004%20Mammalia.pdf.

Guillen-Servent, A., C. Ibanez. 2007. Unusual echolocation behavior in small molossid bat, Molossops temmnickii, that forages near background clutter. Behavioral Ecology and Sociology, 61: 1599-1613. Accessed November 05, 2010 at http://www.springerlink.com/content/v946426426476711/.

Jakobsen, L., A. Surlykke. 2010. Vespertilionid bats control the width of their biosonar sound beam dynamically during prey pursuit. Proceedings of the National Academy of Sciences of The United States of America, 107/ 31: 13930-13935. Accessed November 08, 2010 at http://www.pnas.org/content/107/31/13930.full.

Lopez-Gonzalez, C. 1998. "Systematics and Zoogeography of the bats of Paraguay" (On-line pdf). Accessed November 08, 2010 at http://etd.lib.ttu.edu/theses/available/etd-09262008-31295013286827/unrestricted/31295013286827.pdf.

Male, T. 2001. "Terrestrial Ecoregions: Pantanal" (On-line). World Wildlife fund. Accessed December 05, 2010 at http://www.worldwildlife.org/wildworld/profiles/terrestrial/nt/nt0907_full.html.

McCracken, . 2004. "Free Tailed Bats and Mastiff Bats (Molossidae)" (On-line). Grzimek's Animal Life Encyclopedia. Accessed November 05, 2010 at http://www.gale.cengage.com/AnimalLife/.

Myers, P., R. Espinoza, C. Parr, T. Jones, G. Hammond, T. Dewey. 2008. "Animal Diversity Web" (On-line). Accessed December 06, 2010 at http://animaldiversity.org.

Myers, P., R. Wetzel. 1984. Systematics and Zoogeography of the Bats of the Chaco Boreal. Miscellaneous Publications Museum of Zoology, University of Michigan, 165: 1-68. Accessed November 08, 2010 at http://deepblue.lib.umich.edu/bitstream/2027.42/56409///MP165.pdf.

Nava, S., J. Venzal, M. Diaz, A. Mangold, A. Guglielmone. 2007. The Ornithodoros hasei Species group in Argentina. Systematic and Applied Acarology, 12: 27-30.

Silva, J. 2001. "Terrestrial Ecoregions: Cerrado" (On-line). World Wildlife fund. Accessed December 05, 2010 at http://www.worldwildlife.org/wildworld/profiles/terrestrial/nt/nt0704_full.html.

Wilson, D., D. Reeder. 2005. "Wilson and Reeders Mammal Species of the World Third Edition" (On-line). Accessed November 20, 2010 at http://www.bucknell.edu/msw3/browse.asp?id=13801644.

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