Petaurista philippensis

Geographic Range

Indian giant flying squirrels ( Petaurista philippensis ) have a wide distribution in Asia. This species can be found in South Asia, the mainland of Southeast Asia, and central and southern China. In South Asia they have a patchy distribution in Sri Lanka and India, primarily concentrated in the Himalayan Mountains and northeast regions north of Bombay and Rajastan. They have a wide range on the mainland of Southeast Asia; however, they are not present on the Malay Peninsula. China has recorded sightings in Yunnan, Hainan Island, Sichuan, and Shaanxi. Indian giant flying squirrels can also be found on the island of Taiwan.

• Biogeographic Regions
• oriental oriental
  • native native

Habitat

Indian giant flying squirrels are arboreal, nocturnal mammals that live in tree cavities and the tree canopy. They live in deciduous and evergreen forests of South Asia, hardwood forests of Taiwan, and large patches of forests on Hainan Island, where the species is currently thriving. This species can be found in elevations between 100 to 2,500 meters, which includes vegetation zones of: tropical rainforest or subtropical rainforest (0 to 500 m), temperate broad leafed forest (500 to 1,800 m), and temperate mixed forest (1,800 to 2,500 m). These creatures can most often be found on the edges of forests, or within plantations among their primary food source, fig trees .

• Habitat Regions
• temperate temperate
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• forest forest
• rainforest rainforest

Physical Description

Indian giant flying squirrels have a patagium extending from their wrists to their ankles; similar to the well recognized northern flying squirrels , which help them glide on air currents from tree to tree. Even with amazing gliding abilities, they prefer short gliding distances because longer distances require broader landing platforms, which are not always available and the density of the forest may also prohibit lengthy glides. A wide range of pelage color can be seen between the sexes and the location of sightings. Most coloration includes a variation of dark maroon to black dorsal pelage with white tips, sometimes giving a grey hue and a lighter brown to white on their ventral side. At birth, Indian giant flying squirrels weigh approximately 56 grams; adults can weigh up to 1.65 kilograms. Males generally weigh about 1,260 grams and females weigh approximately 1,334 grams. In a study investigating sexual dimorphism, the skull of Indian giant flying squirrels showed little difference between the sexes.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• sexes alike

Reproduction

Little is known about the mating system of P. philippensis . Due to the location and home range size of the males, data suggests a polygynous or promiscuous mating system. During the mating season, the male may alter his diet and activities to cope with reproduction, by spending more time finding a mate and less time eating. Adult flying squirrels have two annual breeding seasons; one occurring from February to March and the second from July to August. Breeding lasts for two weeks, females mate with an average of 3 to 5 males.

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

Breeding occurs in two seasons, February to March and July to August, each breeding cycle lasts two weeks. Females mate with several males and produce at least one offspring per season. A litter of two has been recorded; however, documentation is rare. After breeding, gestation occurs for approximately 46 days. Live young are born within the tree cavity the squirrel occupies and they are only raised by their biological mother. Offspring are completely weaned after three months and at 95 days old, male offspring become independent, while at 185 days old female offspring are independent.

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

Young flying squirrels are raised by their mother, only until they become independent at 95 to 185 days old.

• Parental Investment
• precocial precocial
• female parental care female parental care

Lifespan/Longevity

The lifespan of Indian giant flying squirrels has not yet been documented. However, the longest known living specimen was alive at age 11 in captivity. Other giant flying squirrels in Asia live an average of 6 years in the wild and 10 to 15 years in captivity. The difference between these rates is believed to represent the important role flying squirrels play as prey to other animals.

Behavior

Indian giant flying squirrels are solitary, nocturnal animals, leaving their nests shortly after dusk and returning before dawn. On average, they spend 9 to 13 hours out in the open, increasing their duration of activity when the length of nightfall increases. These squirrels predominately show crepuscular activity patterns, with increased activity around dawn and dusk. However, their activity patterns varied per month. During the winter to early spring, the species became less active near midnight, resting more often and feasting on mature leaves. From spring to early summer, they become active nearly all night.

• Key Behaviors
• arboreal arboreal
• glides
• nocturnal nocturnal
• motile motile
• solitary solitary

Home Range

The average home range for an adult male is 4 hectares and 2.2 hectares for an adult female. Depending on the influence of diet and the number of receptive females, a male's home range may increase. Diet and gliding efficiency also play a role in range size. Smaller gliders have an energetic advantage, compared to the heavier bodies of larger gliders. However, larger gliders are more energy efficient, not having to land and leap so often. Folivores, such as P. philippensis , also require a smaller home range, when compared to their smaller relatives, due to the leaf abundance in their habitat. This abundance also means they do not have to glide as frequently. Daily range distances average 255 to 640 meters for adults, traveling further in the summer for higher quality food resources. Different individuals are affected by different environmental factors. Some travel less with increased rainfall, while some travel less with a high abundance of mature leaf quantity. However, lactating females may increase their range and activity more than non-lactating females, due to the high energy demands of milk production.

Communication and Perception

Little information has been found in regards to communication and perception of Indian giant flying squirrels. However, having larger eyes in relation to body size implies highly developed vision, which is used in their nocturnal activities. Similar flying squirrels also have well adapted hearing, touch, and smell, as many other arboreal nocturnal species. Other flying squirrel species have vibrissae on their chin, cheeks, and ankles that help them navigate at night. Many others communicate by auditory, visual, and chemical cues, such as for reproduction, although currently, there is no data available specific to Indian giant flying squirrels.

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

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

Food Habits

A diet typical of this species consists mostly of, but not limited to, fruits and leaves of ficus trees. Unlike other flying squirrels, they do not eat insects or other animal matter. Indian giant flying squirrels are folivorous, however, they will also eat bark, fruit, leaves, flowers, and sometimes lichens. Most frequently, they consume ficus fruits, which are an easily accessible source of energy. They are rich in calcium, minerals, low in fat content, and a possible source of animal protein, as provided by larvae of fig wasps. Indian giant flying squirrels prefer mature leaves to immature leaves. More mature leaves are consumed in February and December, when ficus trees do not have such a high abundance of fruit. Feeding is more common along the edge of the forest, where light affects plant physiology. A greater abundance of light results in greater leaf production. It is not yet known whether they consume more ficus fruits or mature leaves.

Indian giant flying squirrels can also be found within plantations, where two thirds of their diet consists of ficus and jackfruit . This species is also known to be opportunistic at exploiting food resources in disturbed areas where logging occurs. The ability to consume leaf material, bark, and even sap at impacted sites indicates that Indian giant flying squirrels are tolerant to habitat disturbances.

• Primary Diet
• herbivore herbivore
  • folivore folivore
  • frugivore frugivore

• Plant Foods
• leaves
• wood, bark, or stems
• fruit
• flowers
• sap or other plant fluids
• lichens

Predation

To avoid being detected by predators, flying squirrels glide and immediately move to the other side of the tree on which they land. Their most common predators are large owls . Other predators include arboreal snakes , raccoons , martens , fishers , and domestic house cats , all of which prey mainly on juvenile flying squirrels. Black crested gibbons ( Nomascus concolor jingdongensis ) are a newly discovered predator. These endangered primates have been seen reaching into nests, pulling out juvenile flying squirrels and swinging them by the tail to kill them against trees and rocks. Once the gibbon kills the squirrel, the carcass is eaten and shared with the gibbon's offspring. Most predation occurs on juvenile squirrels; however, gibbons do attack adults, usually unsuccessfully.

Ecosystem Roles

Although they are primarily folivorous, they do consume other plant materials, which could contribute to seed dispersal. However, this species has been known to occupy plantations and could be a potential pest.

• Ecosystem Impact
• disperses seeds

Economic Importance for Humans: Positive

Little information was found on the economic importance of this species; however, this species may be a good seed disperser.

Economic Importance for Humans: Negative

Little information was found on their economic importance; however, this species could become problematic when they occupy plantations.

• Negative Impacts
• crop pest

Conservation Status

Currently, Petaurista philippensis is listed by the IUCN as a species of least concern. This is possibly due to their widespread distribution, common in Southeast Asia and Taiwan, as well as their adaptability to environments with human impacts, such as logging sites.

Additional Links

Encyclopedia of Life

Contributors

Brandi Ringgenberg (author), University of Alaska Fairbanks, Laura Prugh (editor), University of Washington, Leila Siciliano Martina (editor), Texas State University.

References

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