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. (Nandini and Parthasarathy, 2008; Oshida, et al., 2011; Walston, et al., 2012)
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. ("Petaursista philippensis", 2012; Koli, et al., 2011; Smith and Xie, 2008; Song, et al., 2012)
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. (Lin, et al., 2011)
Young flying squirrels are raised by their mother, only until they become independent at 95 to 185 days old. (Lin, et al., 2011)
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. ("The Animal Ageing and Longevity Database: AnAge entry for Petaurista philippensis", 2012; Pai, 2009)
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. (Kuo and Lee, 2012; Lin, et al., 2011)
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 (Kuo and Lee, 2012), 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.
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. (Cruz, 2011; Fox and Mulheisen, 1999; Malamuth and Mulheisen, 1999)
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. (Nandini and Parthasarathy, 2008)
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. (Nandini and Parthasarathy, 2008)
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. (Fan and Jiang, 2009; Smith and Xie, 2008)
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. (Nandini and Parthasarathy, 2008)
Little information was found on the economic importance of this species; however, this species may be a good seed disperser. (Nandini and Parthasarathy, 2008)
Little information was found on their economic importance; however, this species could become problematic when they occupy plantations. (Nandini and Parthasarathy, 2008)
Brandi Ringgenberg (author), University of Alaska Fairbanks, Laura Prugh (editor), University of Washington, Leila Siciliano Martina (editor), Animal Diversity Web Staff.
uses sound to communicate
Referring to an animal that lives in trees; tree-climbing.
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.
uses smells or other chemicals to communicate
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.
parental care is carried out by females
an animal that mainly eats leaves.
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
an animal that mainly eats fruit
An animal that eats mainly plants or parts of plants.
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).
having the capacity to move from one place to another.
the area in which the animal is naturally found, the region in which it is endemic.
active during the night
found in the oriental region of the world. In other words, India and southeast Asia.
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
having more than one female as a mate at one time
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.
breeding is confined to a particular season
reproduction that includes combining the genetic contribution of two individuals, a male and a female
uses touch to communicate
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).
Living on the ground.
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
uses sight to communicate
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
young are relatively well-developed when born
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