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.
- Biogeographic Regions
- oriental
- australian
- oceanic islands
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.
- Habitat Regions
- tropical
- Terrestrial Biomes
- forest
- rainforest
- 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.
- Other Physical Features
- endothermic
- bilateral symmetry
- Sexual Dimorphism
- male larger
- sexes colored or patterned differently
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.
- Key Reproductive Features
- seasonal breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- post-partum estrous
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
-
protecting
-
pre-hatching/birth
-
provisioning
- female
-
protecting
- female
-
provisioning
-
pre-weaning/fledging
-
provisioning
- female
-
protecting
- female
-
provisioning
-
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.
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.
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.
- Communication Channels
- acoustic
- Other Communication Modes
- vibrations
- Perception Channels
- tactile
- echolocation
- chemical
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.
- Primary Diet
- herbivore
- 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.
- 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.
- 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.
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.
Additional Links
Contributors
Olivia Schiefelbein (author), University of Wisconsin-Stevens Point, Christopher Yahnke (editor), University of Wisconsin-Stevens Point, Leila Siciliano Martina (editor), Texas State University.
- oriental
-
found in the oriental region of the world. In other words, India and southeast Asia.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- Australian
-
Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- 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.
- 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.
- 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.
- 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.
- migratory
-
makes seasonal movements between breeding and wintering grounds
- 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
- vibrations
-
movements of a hard surface that are produced by animals as signals to others
- tactile
-
uses touch 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.
- chemical
-
uses smells or other chemicals to communicate
- food
-
A substance that provides both nutrients and energy to a living thing.
- herbivore
-
An animal that eats mainly plants or parts of plants.
- frugivore
-
an animal that mainly eats fruit
- nectarivore
-
an animal that mainly eats nectar from flowers
- 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.
References
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.
Heideman and Utzurrum. 2003. Seasonality and synchrony of reproduction in three species of nectarivorous Philippines bats. BMC Ecology , 3/11: 341-354.