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.
- Biogeographic Regions
- neotropical
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.
- Habitat Regions
- temperate
- tropical
- terrestrial
- Terrestrial Biomes
- savanna or grassland
- forest
- rainforest
- scrub forest
- Other Habitat Features
- suburban
- agricultural
- caves
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.
- Other Physical Features
- endothermic
- homoiothermic
- bilateral symmetry
- Sexual Dimorphism
- male larger
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.
- Mating System
- polygynous
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.
- Key Reproductive Features
- seasonal breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
Females dwarf dog-faced bats nurse their pups until they are weaned.
- Parental Investment
-
pre-hatching/birth
-
provisioning
- female
-
protecting
- female
-
provisioning
-
pre-weaning/fledging
-
provisioning
- female
-
provisioning
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.
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.
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.
- Other Communication Modes
- scent marks
- Perception Channels
- tactile
- ultrasound
- echolocation
- chemical
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.
- Primary Diet
- carnivore
- 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
.
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.
- Blood flies Nycteribiidae
- Ticks Ornithodoros
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.
- 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.
- Negative Impacts
-
injures humans
- bites or stings
- causes disease in humans
Conservation Status
Dwarf dog-faced bats are abundant and are listed as a species of "least concern" on
the IUCN Red List.
Other Comments
There are three subspecies of dwarf dog-faced bats:
Molossops temminckii sylvia
,
Molossops temminckii temminckii
, and
Molossops temminckii griseiventer
.
Additional Links
Contributors
Gavin Busby (author), University of Oregon, Stephen Frost (editor), University of Oregon, Gail McCormick (editor), Animal Diversity Web Staff.
- Neotropical
-
living in the southern part of the New World. In other words, Central and South America.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- 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).
- tropical
-
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
- terrestrial
-
Living on the ground.
- 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.
- forest
-
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
- 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.
- scrub forest
-
scrub forests develop in areas that experience dry seasons.
- suburban
-
living in residential areas on the outskirts of large cities or towns.
- agricultural
-
living in landscapes dominated by human agriculture.
- 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.
- 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.
- polygynous
-
having more than one female as a mate at one time
- 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
- nocturnal
-
active during the night
- motile
-
having the capacity to move from one place to another.
- social
-
associates with others of its species; forms social groups.
- 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.
- acoustic
-
uses sound to communicate
- chemical
-
uses smells or other chemicals to communicate
- scent marks
-
communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them
- tactile
-
uses touch to communicate
- ultrasound
-
uses sound above the range of human hearing for either navigation or communication or both
- 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.
- chemical
-
uses smells or other chemicals to communicate
- 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).
- carnivore
-
an animal that mainly eats meat
- insectivore
-
An animal that eats mainly insects or spiders.
References
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