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.
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
- tropical
- terrestrial
- Terrestrial Biomes
- forest
- 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
- homoiothermic
- 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
- 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
- seasonal breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- viviparous
Young flying squirrels are raised by their mother, only until they become independent
at 95 to 185 days old.
- Parental Investment
- precocial
- 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.
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.
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.
- 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
Contributors
Brandi Ringgenberg (author), University of Alaska Fairbanks, Laura Prugh (editor), University of Washington, Leila Siciliano Martina (editor), Animal Diversity Web Staff.
- 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.
- temperate
-
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
- tropical
-
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
- terrestrial
-
Living on the ground.
- 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.
- 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.
- polygynous
-
having more than one female as a mate at one time
- polygynandrous
-
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
- 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).
- 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
- viviparous
-
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
- young precocial
-
young are relatively well-developed when born
- female parental care
-
parental care is carried out by females
- arboreal
-
Referring to an animal that lives in trees; tree-climbing.
- nocturnal
-
active during the night
- motile
-
having the capacity to move from one place to another.
- solitary
-
lives alone
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- acoustic
-
uses sound to communicate
- chemical
-
uses smells or other chemicals to communicate
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- acoustic
-
uses sound to communicate
- chemical
-
uses smells or other chemicals to communicate
- herbivore
-
An animal that eats mainly plants or parts of plants.
- folivore
-
an animal that mainly eats leaves.
- frugivore
-
an animal that mainly eats fruit
References
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Song, L., Y. Fa-Hong, L. Xuew-Fei. 2012. Cranial morphometric study of four giant flying squirrels ( Petaurista ) ( Rodentia : Sciuridae ) from China. Zoological Research , 33/2: 119-126. Accessed October 30, 2012 at Doi: 10.3724/SP.J.1141.2012.02119 .
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