Geographic Range
Chrotopterus auritus
occur in southern Mexico, through Central America, and into northern Argentina.
- Biogeographic Regions
- neotropical
Habitat
Big-eared woolly bats tend to live near streams and other moist areas in forested
lowlands, tropical rainforests, tropical deciduous forests, and cloud forests. They
have been reported to roost in hollow trees, caves, and even Mayan ruins.
- Habitat Regions
- tropical
- terrestrial
- Terrestrial Biomes
- forest
- rainforest
- Other Habitat Features
- caves
Physical Description
Big-eared woolly bats are large bats in the New World phyllostomid group which includes
Phyllostomus hastatus
,
Phylloderma stenops
, and
Vampyrum spectrum
, the only other bats similar in size. Big-eared woolly bats range from 100 to 112
mm in length with males weighing about 72.7 g and females about 90.5 g. Males also
have large glands, often located on the middle of the upper chest, which release scents
that serve as sexual identifiers. Females occassionally have these glands as well,
but they release no scent. Wings of
C. auritus
are elliptical in outline with pointed tips and a high wing loading which makes them
more maneuverable. The forearm is about 75 to 87 mm in length. Additionally, their
tails are very short, with a length of 7 to 17 mm.
Big-eared woolly bats have long (12 mm), soft, dark brown hair on their upper parts
and shorter, paler, grayish brown hair on its lower parts. The front of the neck has
a small glandular pocket similar to many other species of bats. Their heads are robust,
with a wide rostrum and large, separate, ovate ears. They have smooth lips and chin
except for a small wart on the center of the lower lip and small elevations on either
side of the lips. They have six incisors: four on the top and two on the bottom. The
regular W shape pattern of molars in bats is modified on the upper molars. They also
have large, curved claws as well as long thumbs used to latch the wings together around
prey.
- Other Physical Features
- endothermic
- homoiothermic
- bilateral symmetry
- Sexual Dimorphism
- female larger
Reproduction
There is little known about the mating system of
C. auritus
, although it is thought that
C. auritus
breed and raise a single young before they breed again. It is also not known if
C. auritus
is polygamous or monogamous, but many other tropical bat species in the family
Phyllostomidae
form monogamous groups. The time span that these family units remain together is
unknown.
Big-eared woolly bats have low reproduction rates, typically having just one offspring
per litter. Females have only been reported to be reproductively active during the
second half of the year. Pregnant females, however, have been observed from April
until July. This is consistent with a monestrous cycle, varying geographically. One
female taken into captivity gave birth to a single young after 99 days. They have
a maximum gestation period of 220 days and a maximum weaning time of nine months.
The age of reproductive maturity is between one and two years.
- Key Reproductive Features
- iteroparous
- seasonal breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- viviparous
It is thought that
C. auritus
take care of their young until they are able to survive on their own. Care and feeding
of young bats is almost entirely the mother’s responsibility. Soon after birth the
infant bat attaches to one of the mother’s pectoral mammae and is carried in that
position for a week or two, depending on the size of the infant. The mother continues
to provide for her pup through weaning and occasionally longer.
- Parental Investment
-
pre-fertilization
- provisioning
-
protecting
- female
-
pre-hatching/birth
-
provisioning
- female
-
protecting
- female
-
provisioning
-
pre-weaning/fledging
-
provisioning
- female
-
protecting
- female
-
provisioning
Lifespan/Longevity
It is not known how long C. auritus live in the wild or in captivity.
Behavior
Big-eared woolly bats exist in low population density areas and form complex social
groups that tend to stay together for several years. Colonies can consist of one to
seven individuals, but typically contain three to five individuals.
Big-eared woolly bats tend to be most active at night, during which time their internal
body temperature is about 37 to 39 °C. The body temperature may drop 2 to 3 °C when
the bat is not active during the day. An internal body temperature of less then 20
°C may be fatal for the bat. Big-eared woolly bats exposed to a constant temperature
between 26 and 27 °C rarely have their internal body temperature fall below 32 °C.
Therefore, they are homoeothermic over a wide range of temperatures.
- Key Behaviors
- arboreal
- flies
- nocturnal
- crepuscular
- motile
- social
Home Range
There is no information available on the home range of
Chrotopterus auritus
.
Communication and Perception
Little is known about the communication for
C. auritus
. However, bats in the suborder
Microchiroptera
,to which
C. auritus
belongs, use echolocation, in which high-frequency sounds are emitted to communicate
and “see." Members of the Phyllostomidae family emit low intensity pulses. Bats will
typically emit sounds through their nose or mouth. In the case of
C. auritus
, it would be more likely that the sounds come out of their mouth due to their small
nose size. The signals are not emitted in all directions; little can be sensed behind,
above, or below the bat. When the bats receive the frequencies back they can rotate
their ears to better hear the sound. Mother bats and infants also communicate using
sound and smell, starting shortly after birth. Mothers can identify the vocalization
of their infant among many calling newborns.
- Perception Channels
- visual
- tactile
- acoustic
- ultrasound
- echolocation
- chemical
Food Habits
Big-eared woolly bats are not exclusively carnivores. In fact, they have a flexible
foraging strategy that allows them to eat insects and fruit in addition to extensive
consumption of small vertebrates like bats, opossums, mice, birds, lizards, and frogs.
Big-eared woolly bats have a diet similar to that of
Vampyrum spectrum
and
Trachops cirrhosus
. Big-eared woolly bats have significant seasonal diet changes. In the wet season
they eat more insects because they are more abundant. However, age and sex do not
have any effect on what they eat.
Big-eared woolly bats use audible cues to help them locate prey as well as other bats.
When prey does not move, it is hard for the bat to locate it and thus it loses interest
in the prey. The bat wraps its wings around the prey and locks its thumbs together.
The bat will then kill the prey with a few quick bites to the throat, if eating a
bat or mouse, or the top of the head, if eating a bird. When the prey is dead, the
bat will fly to a perch and eat its food usually starting from the head and working
its way down. Hard to digest objects such as beaks, feathers, tails, back skin, stomachs,
intestines, and wings are rejected by the bat. It can take one to 20 hours for a bat
to eat its meal.
- Primary Diet
-
carnivore
- eats terrestrial vertebrates
- insectivore
- Animal Foods
- birds
- mammals
- amphibians
- reptiles
- insects
- Plant Foods
- fruit
Predation
There are no known predators of big-eared woolly bats nor any recorded cases of natural
death. Most bats are preyed on by owls (
Strigiformes
) in flight or by snakes (
Serpentes
) from roosts.
Ecosystem Roles
Big-eared woolly bats
help to disperse seeds. They also help to keep insect populations under control.
- Ecosystem Impact
- disperses seeds
- pollinates
Economic Importance for Humans: Positive
Big-eared woolly bats contribute to insect control, lowering the need for insecticides. This saves money and decreases the use of toxins.
- Positive Impacts
- controls pest population
Economic Importance for Humans: Negative
Big-eared woolly bats have no known negative impact on humans.
Conservation Status
Big-eared woolly bats are not endangered but deforestation is reducing the area they
can live in and may prove to be a problem in future years.
Additional Links
Contributors
Tanya Dewey (editor), Animal Diversity Web.
Kelly Houseal (author), Kalamazoo College, Ann Fraser (editor, instructor), Kalamazoo College.
- 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.
- 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.
- 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.
- 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.
- 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).
- 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
- viviparous
-
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
- arboreal
-
Referring to an animal that lives in trees; tree-climbing.
- nocturnal
-
active during the night
- crepuscular
-
active at dawn and dusk
- motile
-
having the capacity to move from one place to another.
- social
-
associates with others of its species; forms social groups.
- acoustic
-
uses sound to communicate
- chemical
-
uses smells or other chemicals to communicate
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- acoustic
-
uses sound 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
- carnivore
-
an animal that mainly eats meat
- insectivore
-
An animal that eats mainly insects or spiders.
References
Altringham, J. 1996. Bats: Biology and Behavior . New York: Oxford University Press Inc..
Hill, J., J. Smith. 1984. Bats: A Natural History . United Stated of America: British Museum (Natural History) and University of Texas Press, Austin.
Kunz, T., P. Racy. 1998. Bat Biology and Conservation . Washington: Smithsonian Institute Press.
Medellin, R. 1989. Chrotopterus auritus. Mammilian Species , 343: 1 - 5.
Medellin, R. 1988. Prey of Chrotopterus Auritus, with Notes on Feeding Behavior. Journal of Mamology , 69/4: 841 - 4.
Novic, A. 1969. The World of Bats . Switzerland: Holt, Rinehart, and Winston, Inc..
Nowalk, R. 1994. Walker's bats of the World . United States of America: John Hopkins University Press.
Wimsatt, W. 1970. Biology of Bats, Volume I . New York: Academic Press Inc..
Wimsatt, W. 1977. Biology of Bats, Volume II . New York: Academic Press Inc..