Pteropus giganteus

Geographic Range

Pteropus giganteus occurs in tropical regions of South Central Asia, from Pakistan to China, and as far south as the Maldive Islands.

• Biogeographic Regions
• oriental oriental
  • native native

Habitat

These animals can be found in forests and swamps. Large groups of individuals roost in trees such as banyan, fig, and tamarind. Roosting trees are usually in the vicinity of a body of water.

• Habitat Regions
• tropical tropical

• Terrestrial Biomes
• forest forest
• rainforest rainforest

• Wetlands
• swamp swamp

Physical Description

The physical appearance of this species is similar to that of megachiropterans in general, with large eyes, simple ears, and no facial ornamentation. Dark brown, gray, or black body color with a contrasting yellowish mantle is typical of the genus Pteropus . Body mass ranges from 600 to 1600 g and males are generally larger than females. Wingspan may range from 1.2 to 1.5 m and body length averages 23 cm. Members of the genus Pteropus maintain body temperatures between 33 and 37 C, but must do this through constant activity.

• Other Physical Features
• endothermic endothermic
• heterothermic heterothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• male larger

Reproduction

This species is polygynandrous, with no pair bonds occurring between males and females. Females are defended from intruding males by males that live in their roosting tree.

• Mating System
• polygynandrous (promiscuous) polygynandrous (promiscuous)

Pteropus giganteus breeds yearly, with mating occurring from July to October, and births occurring from February to May. To initiate copulation, a male will fan his wings toward a female, and persistently follow her until he is able to grip the scruff of her neck with his teeth and hold her with his thumbs. Copulation occurs for a duration of 30 to 40 seconds. The female usually vocalizes and physically resists the advances of the male during the encounter. After copulation, the male again follows the female while vocalizing loudly. Gestation period is typically 140 to 150 days, after which 1 to 2 young are born. Like other members of the genus Pteropus , the young are carried by the mother for the first few weeks of life. Sexual maturity for this species occurs at about 1.5 years of age.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• fertilization fertilization
• viviparous viviparous

After birth, young are carried by the mother for the first three weeks of life. They begin to hang by themselves after this time period, but are still carried to feeding sites by the mother. Young learn to fly at about 11 weeks of age and are weaned at 5 months. Males do not participate in parental care.

• Parental Investment
• altricial altricial
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female
• pre-independence
  • protecting
    • female
• inherits maternal/paternal territory

Lifespan/Longevity

The longest lifespan of an individual of this species in captivity was recorded at 31 years, 5 months. Little information is available regarding life expectancy in the wild.

Behavior

Pteropus giganteus is a social species, with large groups of several hundred individuals living in the same tree. Males may maintain a vertical dominance hierarchy of resting spots in the tree, and may also defend the roost and associated females from intruders. During the day, these animals sleep, hanging upside down by their feet with their wings wrapped around themselves. They also fan themselves to aid in thermoregulation, move around in the roosting tree, and communicate with each other. As they are nocturnal, they leave the tree at sunset to feed, returning after several hours of finding food, feeding, digesting, and resting.

• Key Behaviors
• arboreal arboreal
• flies
• nocturnal nocturnal
• motile motile
• territorial territorial
• social social
• colonial colonial
• dominance hierarchies dominance hierarchies

Home Range

The roosting tree is the area in which Indian flying foxes spend the majority of the day. This species, as well as other large species of Pteropus , is reported to travel up to 15 km to find food.

Communication and Perception

Communication among individuals of this species is vocal. They chatter and squawk when threatened. Typical of megachiropterans, P. giganteus does not echolocate, and relies on sight rather than hearing for navigation. Because of their use of vision, there is probably communication involving body postures and positioning. Tactile communication is important during mating, as well as between mothers and their offspring.

• Communication Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Pteropus giganteus is frugivorous, as are other species of the Suborder Megachiroptera, otherwise known as the Old World fruit bats. This species has been reported to eat many different species of fruit, including guava, mango, and fig. An individual of the genus Pteropus squeezes out fruit juices from the pulp against the roof of its mouth, and then discards the dry material. Some Pteropus species also supplement their dietary protein by eating insects. Others, including P. giganteus , eat the blossoms and nectar of fruiting plants.

• Primary Diet
• herbivore herbivore
  • frugivore frugivore

• Plant Foods
• fruit
• nectar
• flowers

Predation

Major predators of this species are humans, snakes and raptors.

Ecosystem Roles

This species, along with other species of the genus Pteropus , plays a role in seed dispersal. It is also eaten by snakes and raptors.

• Ecosystem Impact
• disperses seeds

Economic Importance for Humans: Positive

Humans in some regions benefit from Indian flying foxes by hunting them for food and medicinal purposes.

• Positive Impacts
• food food
• source of medicine or drug source of medicine or drug

Economic Importance for Humans: Negative

Indian flying foxes cause extensive damage to fruit orchards, and are therefore considered pests in many regions. They may also be responsible for spreading disease, particularly the Nipah virus, which causes illness and death in humans.

• Negative Impacts
• injures humans
  • carries human disease
• crop pest

Conservation Status

This species is listed in CITES Appendix II, meaning it is not currently threatened, but could become so if protective measures are not taken.

Other Comments

Although not considered an at risk species, P. giganteus is subject to lethal, officially sanctioned control measures in many areas, including the Maldive Islands, Pakistan, and India, because of their negative effects on fruit orchards. Despite this negative impact, this species is protected and considered sacred by people in certain regions of India.

Additional Links

Encyclopedia of Life

Contributors

Erin Silbernagel (author), University of Alaska Fairbanks, Link E. Olson (editor, instructor), University of Alaska Fairbanks.

Nancy Shefferly (editor), Animal Diversity Web.

References

Altringham, J. 1996. Bats: Biology and Behaviour . Oxford: Oxford University Press.

Koilraj, B., G. Agoramoorthy, G. Marimuthu. 2001. Copulatory Behaviour of Indian flying fox Pteropus giganteus. Current Science , 80/1: 15-16. Accessed February 12, 2004 at http://www.ias.ac.in/currsci/jan102001/15.pdf .

Kunz, T., P. Racey. 1998. Bat Biology and Conservation . Washington: Smithsonian Institution Press.

Marimuthu, G. 1998. The Sacred Flying Fox of India. Bats , 9/2: 10-11. Accessed October 19, 2004 at http://www.batcon.org/batsmag/v6n2-3.html .

Nowak, R. 1999. Walker's Mammals of the world . Baltimore and London: The Johns Hopkins University Press.

Thatcher, O. 2004. "Fruit and Nectar Bat Biology" (On-line). Lubee Bat Conservacy. Accessed October 19, 2004 at http://www.lubee.org/about-biology.aspx .

The Minnesota Zoo. 2002. "Greater Indian Fruit Bat (Indian Flying Fox)" (On-line). Minnesota Zoo. Accessed February 12, 2004 at http://www.mnzoo.com/animals/tropics_trail/fbat_1.asp .

2004. "Indian Flying Fox (Pteropus giganteus)" (On-line). Utah's Hogle Zoo. Accessed February 12, 2004 at http://www.hoglezoo.org/animals/view.php?id=82 .

ICDDR,B: Centre for Health and Population Research. 2002. "Nipah Encephalitis Outbreak Over Wide Area of Western Bangladesh" (On-line). ICDDR,B: Centre for Health and Population Research. Accessed February 12, 2004 at http://202.136.7.26/pub/publication.jsp?classificationID=56&pubID=5144 .