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Rousettus amplexicaudatusGeoffroy's rousette

By Olivia Schiefelbein

Geographic Range

Geoffroy's rousettes (Rousettus amplexicaudatus) are found in the the Australasian region, from Myanmar (Burma) to the Solomon Islands. They can be found in countries including, but not limited to the Philippines, Malaysia and Papua New Guinea. (Mould, 2012; "Seasonality and synchrony of reproduction in three species of nectarivorous Philippines bats", 2003; Kompanje, 2001; Sanchez-Villagra, 2006; Zubaid, 2004)

Habitat

Geoffroy's rousettes are found in subtropical and tropical areas. They prefer lower elevations near coasts. These bats roost in large limestone caves near primary or secondary forests. These caves are never far from human habitation, and plantations are often nearby. They roost in large numbers with more than 2,000 bats at a roost. A roosting site of 1.8 million individuals has been observed, however, this large group might be due mostly to their small area of protected habitat. The caves occupied by Geoffroy's rousettes may be inhabited by other species of fruit bats, although Geoffroy's rousettes tend to be more numerous. (Mould, 2012)

  • Other Habitat Features
  • caves

Physical Description

Geoffroy's rousettes have brown or grey-brown bodies, their heads are usually darker than their underparts. Their fur is short, with longer, sometimes yellow hairs around their neck and chin, most commonly seen in males. Males of this species are much larger than females. They vary in forearm length from 82.22 to 86.76 mm, the length of their bodies range from 78 to 87 mm. (Payne and Francis, 1985)

  • Sexual Dimorphism
  • male larger
  • sexes colored or patterned differently
  • Range length
    78 to 87 mm
    3.07 to 3.43 in

Reproduction

Not much is known about the mating system of Geoffroy's rousettes.

Geoffroy's rousettes have young twice a year, they breed between December and January and also May and June. The first birth is grouped around March and April; the second birthing period is around August and September. Females become pregnant shortly after giving birth and lactate during their second pregnancy of the year. Their gestation period is 150 days and they lactate for 60 days. Individuals that are pregnant for the first time only have one offspring their first year, most likely to increase their chances of at least one surviving offspring. ("Seasonality and synchrony of reproduction in three species of nectarivorous Philippines bats", 2003)

  • Key Reproductive Features
  • seasonal breeding
  • gonochoric/gonochoristic/dioecious (sexes separate)
  • sexual
  • post-partum estrous
  • Breeding interval
    Breed twice a year
  • Breeding season
    December/January and May/June
  • Average number of offspring
    1
  • Range gestation period
    3.5 to 4.5 months
  • Range weaning age
    2.5 to 3 months
  • Range age at sexual or reproductive maturity (female)
    6 to 9 months

The parental involvement of Geoffroy's rousettes is unknown. In most bats, females take a larger role in the upbringing.

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

Lifespan/Longevity

It is unknown how long these bats live in captivity or in the wild.

Behavior

Geoffroy's rousettes roost in large numbers. They have a large geographic range and migrate to follow fruit ripening. (Kompanje, 2001; Zubaid, 2004)

Home Range

Geoffroy's rousettes have been known to travel up to 25 km from roost sites to foraging sites. These bats also fly over water barriers and agricultural areas to reach their foraging and roosting sites. ("Seasonality and synchrony of reproduction in three species of nectarivorous Philippines bats", 2003; Kompanje, 2001)

Communication and Perception

Rousettus is the only genus of echolocating Old World fruit bats. They produce sonar clicks with their tongue; their clicks are extremely short at about 50 to 100 microseconds per click. (Mould, 2012; Zubaid, 2004)

Food Habits

Geoffroy's rousettes consume nectar and pollen. When in season, these bats also feed on soft ripe fruit, usually in orchards. Geoffroy's rousettes have been known to fly more than 38 km to forage for food in a single night. They form large groups when feeding upon large areas of food, such as orchards or groups of fig trees. ("Seasonality and synchrony of reproduction in three species of nectarivorous Philippines bats", 2003; Zubaid, 2004)

  • Plant Foods
  • fruit
  • nectar
  • pollen

Predation

Little is known about the predators of Geoffroy's rousettes. Their biggest threat seems to come from humans.

Ecosystem Roles

Geoffroy's rousettes consume fruit, if the seeds are small enough they will digest them and drop them in their feces. If the seeds are bigger, they spit them out. At times, bats travel with seeds in their mouths before spitting them out. (Zubaid, 2004)

  • Ecosystem Impact
  • disperses seeds

Economic Importance for Humans: Positive

Geoffroy's rousettes are often hunted for food, and their guano is collected as a delicacy in many native tribes. Both of these collections can be used as a form of cash crop or as trade and barter items. (Mould, 2012)

  • Positive Impacts
  • food
  • body parts are source of valuable material

Economic Importance for Humans: Negative

There are no known negative impacts of Geoffroy's rousettes. They have been known to feed in orchards, but not often enough to classify them as a crop pest. (Zubaid, 2004)

Conservation Status

Geoffroy's rousettes are currently listed as a species of least concern on the IUCN Red List. They are not listed under CITES or the U.S Endangered Species Act. Some activities threatening Geoffroy's rousettes are habitat destruction of caves through tourism and land development. They are also hunted for food and guano. (Mould, 2012)

Contributors

Olivia Schiefelbein (author), University of Wisconsin-Stevens Point, Christopher Yahnke (editor), University of Wisconsin-Stevens Point, Leila Siciliano Martina (editor), Animal Diversity Web Staff.

Glossary

Australian

Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

World Map

acoustic

uses sound to communicate

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.

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.

food

A substance that provides both nutrients and energy to a living thing.

forest

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

frugivore

an animal that mainly eats fruit

herbivore

An animal that eats mainly plants or parts of plants.

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.

nectarivore

an animal that mainly eats nectar from flowers

nocturnal

active during the night

oceanic islands

islands that are not part of continental shelf areas, they are not, and have never been, connected to a continental land mass, most typically these are volcanic islands.

oriental

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

World Map

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

tactile

uses touch to communicate

tropical

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

vibrations

movements of a hard surface that are produced by animals as signals to others

References

Heideman and Utzurrum. 2003. Seasonality and synchrony of reproduction in three species of nectarivorous Philippines bats. BMC Ecology, 3/11: 341-354.

Kompanje, E. 2001. Some fruit bats from remote Moluccan and West-Papuan Islands, with the description of a new subspecies of Macroglossus minimus (Megachiroptera: Pteropodidae). Deinsea, 8: 143-167.

Mould, A. 2012. Cave bats of the central west coast and southern section of the Northwest Panay Peninsula, Panay Island, the Philippines. Journal of Threatened Taxa, 4/11: 2993-3028.

Payne, J., C. Francis. 1985. A Field Guide to the Mammals of Borneo. Malaysia: Sabah Society.

Sanchez-Villagra, M. 2006. Development of Integumentary Structures in Rousettus amplexicaudatus (Mammalia: Chiroptera: Pteropodidae) During Late-Embryonic and Fetal Stages. Journal of Mammalogy, 87/5: 993-1001.

Zubaid, A. 2004. Temporal Variation in the Relative Abundance of Fruit Bats (Megachiroptera: Pteropodidae) in Relation to the Availability of Food in a Lowland Malaysian Rain Forest. BioTropica, 36/4: 522-533.

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