Diclidurus albusnorthern ghost bat

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Geographic Range

Diclidurus albus is rare but widespread, ranging from Mexico to eastern Brazil. It is also found on some Caribbean Islands including Trinidad. During the summer months no sightings of D. albus have been made in Mexico, the northern edge of its range. This suggests that members of this species migrate south seasonally, from May to October. Little information is available on D. albus migration patterns. (Ceballos and Medellin, 1988; Jones and Hood, 1993; Ceballos and Medellin, 1988; Jones and Hood, 1993; Ceballos and Medellin, 1988; Eisenberg and Redford, 1999; Jones and Hood, 1993)

Habitat

Northern ghost bats prefer humid habitats like riparian and tropical rainforests but have been found in human-disturbed areas like plantations, clearings, and over villages. They prefer to roost underneath the fronds of palms, including coconut, chocho palms, and coquito palms. These bats have also been seen in less mesic habitats, like deciduous and evergreen forests. Diclidurus albus migrates within the Neotropics. They occur from sea level to 1500 m. They were observed at highest elevations in Costa Rica. (Ceballos and Medellin, 1988; Eisenberg and Redford, 1999; Jones and Hood, 1993; LaVal, 2004)

  • Range elevation
    0 to 1500 m
    0.00 to 4921.26 ft

Physical Description

Diclidurus albus is a distinctive looking bat species. The common name, northern ghost bats, refers to their soft, long, white pelage. Sometimes the proximal ends of the hairs are grey in color, while the distal ends are white, giving the animal an ashy grey tone. The patagia are pinkish and translucent and the tail is short, about one third the length of the uropatagium. The tail punctures the uropatagium, with the end projecting dorsally. The uropatagium is large with about two-thirds covered in fur, and extends beyond the hind feet. Northern ghost bats have nearly naked faces with large eyes and shorter, yellowish ears. They do not have a nose leaf, and their tragus is prominent, broad, and rounded. (Ceballos and Medellin, 1988; Eisenberg and Redford, 1999; Engstom and Lim, 1999; Jones and Hood, 1993; Vaughan, et al., 2000)

Diclidurus albus lacks the wing sacs that other Emballonuridae have. Instead, these bats have a unique gland on their uropatagium. This gland has two valves and is triangular in shape. Its actual function isn’t known, but it is larger in males, and becomes even more prominent during the breeding season. Northern ghost bats have vestigial thumbs, unlike other species in the genus. (Ceballos and Medellin, 1988; Engstom and Lim, 1999; Jones and Hood, 1993)

The skull is distinctive. The rostrum angles upward steeply from the braincase. The zygomatic arches are complete and the skull has strong supraorbital ridges. Premaxillae do not meet and have nasal branches only. The canines project forward and outward. The dental formula is I: 1/3, C: 1/1, PM: 2/2, M: 3/3 = 32. Cheek teeth are dilambdodont and have cingula. (Ceballos and Medellin, 1988; Jones and Hood, 1993; Vaughan, et al., 2000)

Northern ghost bats are at the larger end of the size range for Emballonuridae, with total lengths ranging from 86.0 mm to 103.0 mm. Tail lengths vary between 18.0 mm and 22.0 mm. Diclidurus albus differs from its congeners in that the length of its forearm is between 60 mm and 70 mm, while other species of this genus have forearms less than 60 mm or above 70 mm, or are distinguished by brownish pelage. Adult D. albus weigh between 17 and 24 g. They are sexually dimorphic; females tend to be larger in size and length, but this varies regionally. For example, in Mexico, both sexes were very similar in all measurements. The average female length was 88.0 mm, with the average male length being 89.0 mm. In Guatemala, however, females were about 10 mm longer than the males, with an average length of 102.0 mm compared to 92.5 mm for males. Sample sizes are relatively small, however, and more research is needed to verify the presence of sexual dimorphism in D. albus. (Ceballos and Medellin, 1988; Engstom and Lim, 1999; Hernandez, et al., 1985; Jones and Hood, 1993; Vaughan, et al., 2000)

  • Sexual Dimorphism
  • female larger
  • Range mass
    17.0 to 24.0 g
    0.60 to 0.85 oz
  • Average mass
    20.0 g
    0.70 oz
  • Range length
    86.0 to 103.0 mm
    3.39 to 4.06 in
  • Range wingspan
    63.0 to 69.2 mm
    2.48 to 2.72 in

Reproduction

There is little information on the mating system of D. albus. Northern ghost bats are solitary except during the breeding season. During this time, small groups of bats can been seen roosting very close together. There is usually a maximum of four individuals, and the group consists of one male and multiple females. The triangular gland present on the uropatagium of D. albus grows in size during the breeding season, and may be used by males to attract females. (Ceballos and Medellin, 1988; Jones and Hood, 1993)

Breeding occurs during the months of January and February. Pregnant females have been found between the months of January and June. Single young are usually born in May or June. The breeding season occurs only once a year, so D. albus is monestrus. The timing of weaning and the age at sexual maturity are unknown. Diclidurus albus is a rare animal to see, so its reproductive behaviors have yet to be studied in depth. (Ceballos and Medellin, 1988; Hernandez, et al., 1985; Jones and Hood, 1993)

  • Breeding interval
    Northern ghost bats breed once per year.
  • Breeding season
    Diclidurus albus breeds during January and February.
  • Range number of offspring
    1 to 1

Like most other bats, females care for their young by nursing and protecting them. Young bats mature quickly and become independent within a few months of their birth. (Ceballos and Medellin, 1988)

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

Lifespan/Longevity

Northern ghost bat lifespans have not been studied.

Behavior

Northern ghost bats are solitary. They do not form colonies and are found in small groups only during the breeding season. Northern ghost bats are nocturnal and roost under palms during the day. They tend to fly high and in reasonably straight lines. Most studies of D. albus have focused on physical properties instead of behavioral characteristics, so the behavior of this species is not well known. (Ceballos and Medellin, 1988; Eisenberg and Redford, 1999; Engstom and Lim, 1999; Jones and Hood, 1993)

Home Range

The home range size for D. albus is unknown.

Communication and Perception

Northern ghost bats use echolocation to find prey and to navigate their way through the nighttime forest. They emit a call at 22 kHz while hunting. No information is available about communication between individual bats, although chemical communication is likely, including the use of gland secretions by males. (Zorpette, 1999)

Food Habits

Like all members of the family Emballonuridae, northern ghost bats are insectivorous. Stomach contents have a high proportion of moths. (Ceballos and Medellin, 1988; Eisenberg and Redford, 1999; Engstom and Lim, 1999; Jones and Hood, 1993)

  • Animal Foods
  • insects

Predation

Northern ghost bats are nocturnal and solitary, which helps to protect them from many predators. Predation on northern ghost bats has not been recorded.

Ecosystem Roles

Northern ghost bat individuals eat around 1,000 insects a night. This could affect insect populations. These bats are rare, so their effect on the ecosystem are probably slight and can only be a hypothesized based on the effects of other bats in the area. Also, bat guano is very important to plants, providing excellent fertilizer. (Zorpette, 1999)

Economic Importance for Humans: Positive

Northern ghost bats may be important in helping keep agricultural pest populations in check, but their rarity suggests that they might not contribute much to insect control. Also, because this bat is attractively colored and rare, may help draw ecotourists to an area. With knowledgeable guides, nighttime bat tours can attract tourists. (Lim and Engstrom, 2005; Zorpette, 1999)

  • Positive Impacts
  • ecotourism
  • produces fertilizer
  • controls pest population

Economic Importance for Humans: Negative

Like most wild mammals, northern ghost bats can transmit rabies to humans and other animals. However, rabies transmission to humans is rare. (Jones and Hood, 1993)

Conservation Status

IUCN lists D. albus as being at lower risk and least concern. Although northern ghost bats are rare throughout their range, they are widespread. (Chiroptera Specialist Group 1996, 2004)

Other Comments

Two subspecies are sometimes recognized, D. a. albus and D. a. virgo. Previously, Diclidurus scutatus was considered a synonym of D. albus, but is now considered a separate species, about which very little is known. Controversy abounds over who deserves the credit for naming D. albus. Oken may have been responsible, but credit is usually given to Wied (1820). No fossils are known for the entire genus Diclidurus. Other common names include murciélagos blancos (Spanish), and gespenstfliedermaus (German). The generic name, Diclidurus arises from the gland on the tail. The Latin word diclid means two-valved, and urus means tail. Albus in Latin means white, and relates to the white fur of these bats. (Ceballos and Medellin, 1988; Jones and Hood, 1993)

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Ashley Potchynok (author), University of Michigan-Ann Arbor, Phil Myers (editor, instructor), Museum of Zoology, University of Michigan-Ann Arbor.

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).

causes or carries domestic animal disease

either directly causes, or indirectly transmits, a disease to a domestic animal

chemical

uses smells or other chemicals to communicate

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.

ecotourism

humans benefit economically by promoting tourism that focuses on the appreciation of natural areas or animals. Ecotourism implies that there are existing programs that profit from the appreciation of natural areas or animals.

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.

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).

migratory

makes seasonal movements between breeding and wintering grounds

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.

riparian

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

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

solitary

lives alone

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

visual

uses sight 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

Ceballos, G., R. Medellin. 1988. Diclidurus albus. Mammalian Species, 316: 1-4.

Chiroptera Specialist Group 1996, 2004. "Diclidurus albus" (On-line). The IUCN Red List of Threatened Species. Accessed March 21, 2006 at http://www.iucnredlist.org/search/details.php?species=6561.

Eisenberg, J., K. Redford. 1999. Mammals of the Neotropics: The Central Neotropics: Ecuador, Peru, Bolivia, Brazil. Chicago: University of Chicago Press.

Engstom, M., B. Lim. 1999. "Northern Ghost Bat" (On-line). Iwokrama. Accessed March 21, 2006 at http://www.iwokrama.org/mammals/guides/bats0.html#dial.

Hernandez, C., C. Tapia, A. Garduno, E. Corona, M. Hidalgo. 1985. Notes on Distribution and Reproduction of Bats from Coastal Regions of Michoacan, Mexico. Journal of Mammalogy, 66/3: 549-553. Accessed March 21, 2006 at http://www.jstor.org/view/00222372/ap050268/05a00170/0.

Jones, J., C. Hood. 1993. Synopsis of South American Bats of the Family Emballonuridae. Occasional Papers The Museum Texas Tech University, 155: 1-32. Accessed March 21, 2006 at http://www.loyno.edu/~chood/joneshood1993.pdf.

LaVal, R. 2004. Impact of Global Warming and Locally Changing Climate on Tropical Cloud Forest Bats. Journal of Mammalogy, 85/2: 237-244.

Lim, B., M. Engstrom. 2005. Mammals of Iwokrama Forest. Proceedings of the Academy of Natural Sciences of Philadelphia, 154: 71-108.

Vaughan, T., J. Ryan, N. Czaplewski. 2000. Mammalogy Fourth Edition. Australia: Brooks/Cole.

Zorpette, G. 1999. Chasing the Ghost Bat. Scientific American, 280/6: 82-89.