It is found in a wide variety of forest–types, plantations and more open habitats with scattered trees in Southeast Asia, ranging north to the Himalayas and southern and central China.

[5] Although declining locally due to habitat loss and to a lesser degree hunting, it remains overall common and it is not a threatened species.

The distribution of this group essentially equals the Sundaic region, including Java, Sumatra, Borneo, the Thai-Malay Peninsula, nearby smaller islands, and Singapore (last Singaporean record in 1986, possibly extirpated).

[3][10] Members of the nominate group are medium to dark reddish-brown above and the underparts, including the face, are light orangish-brown to buff.

The various subspecies in this group are generally quite similar, varying primarily in the exact hue of the upper- and underparts, and to a small degree their size.

[21] Members of the barroni–candidula subspecies group are chestnut-brown above with the central parts, from the nape to the rump, with many whitish hairs resulting in a grizzled appearance.

[18] Based on a small number of specimens, members of the barroni–candidula subspecies group are medium-large in size, with measurements in the mid to upper range of that reported for the red giant flying squirrel.

In contrast, candidula was considered a subspecies of the red and white giant flying squirrel based on its colours.

[4] The white-bellied giant flying squirrel (albiventer) is from the western and central Himalayan region in northeastern Afghanistan, through northern Pakistan and northern India, at least to Nepal (formerly reported east to Yunnan in China, but this is now recognized as separate, see Yunnan giant flying squirrel).

[14][15] As a consequence, recent authorities often have recognized it as a separate species, the white-bellied giant flying squirrel (P. albiventer), sometimes with barroni or members of the yunanensis group as its subspecies.

In yunanensis, the central upperparts, from the top of the head and shoulders to the rump, have extensive scattered creamy-white guard hairs resulting in a grizzled appearance.

[24][28] Despite being distantly related, yunanensis is easily confused with the rare Mount Gaoligong flying squirrel (Biswamoyopterus gaoligongensis).

Members of the yunanensis subspecies group are medium-large in size, with measurements in the mid to upper range of that reported for the red giant flying squirrel.

[3][12][24][28] Traditionally, only yunanensis was recognized, variously as a subspecies of the red or the Indian giant flying squirrel, and often including several highly distinctive populations, notably hainana, rubicundus and rufipes, as synonyms.

[30] Despite their appearance, it was suggested in 2005 in Mammal Species of the World that both rubicundus and rufipes should be regarded as synonyms of yunanensis,[22] which was repeated in another taxonomic review in 2012.

[4] The cranial morphometrics of rufipes (data is lacking for rubicundus) differ distinctly from those of the yunanensis subspecies group.

In 1949, the population in southeastern Sumatra (a part of red giant flying squirrel's nominate subspecies group) was described, also using the name rufipes.

Consequently, if both are recognized as valid subspecies of the red giant flying squirrel, the replacement name sodyi is used for the southeast Sumatran population.

It is relatively small in size, with measurements in the lower range of those reported for the red giant flying squirrel.

[4] The red giant flying squirrel is largely nocturnal, starting its activity just before dusk and retreating at dawn.

[35] As long as the separation between remaining tall trees does not exceed its typical glide distance, this species survives well in degraded habitats,[23] even willingly crossing highways.

[35] The red giant flying squirrel is a herbivore, primarily a folivore, and has been recorded feeding on the leaves of many plant species.

[37] Other items recorded in its diet are shoots, flowers, fruits, nuts, seeds, lichen, moss, twigs, bark and in the northern part of its range pine cones.

[3] Although not fully confirmed, there are strong indications that flower-feeding red giant flying squirrels may function as pollinators of certain trees.

[39] The populations that live in colder mountainous regions (for example, P. (p.) albiventer) remain active even when there is deep snow on the ground, but during this time may move to lower altitudes.

[2] It has an oft-uttered call that especially is given at dusk,[5] and in Himalaya (P. (p.) albiventer) has been described as a "monotonous repeated wail" or a "loud, penetrating and drawn-out whine".