Petinomys setosusTemminck's flying squirrel

Geographic Range

Petinomys setosus exhibits an expansive distribution throughout much of Southeast Asia including several isolated populations. The recognized areas of distribution are northwestern and southern Thailand, northern and eastern Myanmar, Sumatra, the northern third of Borneo, the southern peninsular Malaysia, and most recently Lao People’s Democratic Republic. (Sanamxay, et al., 2019; Thorington Jr, et al., 2012; Wilson, et al., 2017)


Petinomys setosus are rather adaptable; they have been located in a variety of habitats including wet tropical rainforests as well as dry deciduous and monsoonal forests. They are particularly inclined to inhabit primary forests but have also been documented in partially cut forests. There are additional reports suggesting P. setosus may occupy areas near fruit and rubber plantations. (Jackson, 2012; Thorington Jr, et al., 2012; Wilson, et al., 2017)

Physical Description

Petinomys setosus are distinguished by the presence of black rings that encircle the eyes and connect to the nose via a black streak. P. setosus display an admixture of black and brown fur on the dorsal side, accompanied by an off-white, cream-colored ventral pelage. The tail is flat and displays similar coloring to the dorsal pelage with patches of white at the base and tip. The following data are mean values from eight specimens in total, one from Lao PDR, three from northern Thailand, and four from western Malaysia. Adapted from Sanamxay et al. 2019: Mass: 42.40 g Head and body length: 116 mm Tail length: 106 mm Ear length: 14.75 mm Hindfoot length: 23 mm Occipitonasal length: 32.12 mm(from Lao PDR specimen only) Condylobasal length: 28.93 mm Mastoid breadth: 16.94 mm (from Lao PDR specimen only) Zygomatic breadth: 19.56 mm (from Lao PDR specimen only) Zygomatic height: 1.65 mm Breadth of braincase: 15.68 mm Braincase height: 10.39 mm Rostrum breadth: 6.31 mm Nasal length: 7.36 mm Maximum width of nasal bones: 4.28 mm Interorbital breadth: 6.41 mm Postorbital breadth: 9.25 mm Length of the incisive foramina: 1.96 mm Length of bony palate: 9.73 mm Postpalatal length: 12.64 mm (from Lao PDR specimen only) Length of auditory bullae: 6.86 mm Interbullae gap: 2.06 mm (from Lao PDR specimen only) P3 –M3: 5.29 mm M2 –M2: 7.53 mm M1 –M1: 4.68 mm Mandible length: 17.19 mm Mandible height: 10.88 mm P4–M3: 5.34 mm (Jackson, 2012; Sanamxay, et al., 2019; Wilson, et al., 2017)

  • Average mass
    42.4 g
    1.49 oz
  • Average length
    116 mm
    4.57 in


There is no known information regarding mating systems for this species. (Hayssen, 2008; Wilson, et al., 2017)

There is little known information on reproduction in Petinomys setosus. Average litter size is likely 1-2 offspring. (Hayssen, 2008; Wilson, et al., 2017)

  • Key Reproductive Features
  • gonochoric/gonochoristic/dioecious (sexes separate)
  • sexual
  • Average number of offspring

There is no known information regarding parental investment for this species. (Hayssen, 2008; Wilson, et al., 2017)


There is little known information regarding life span in the wild or in captivity for this species. The average generation length is estimated to be 3.3 years. (Clayton, 2020)

  • Average lifespan
    Status: wild
    3.3 years


Little is known about the behavior of Petinomys setosus. Currently there is limited information regarding territory size for this species. One study found that a specimen from this species preferred isolated habitats away from human settlements and activities. (Jackson, 2012; Sanamxay, et al., 2019; Wilson, et al., 2017)

Home Range

Currently there is no known information regarding home range for this species.

Communication and Perception

No information about communication is currently known for this species. (Jackson, 2012; Thorington Jr, et al., 2012)

Food Habits

Petinomys setosus has a frugivorous diet of seeds and fruits. (Clayton, 2020; Jackson, 2012)

  • Plant Foods
  • seeds, grains, and nuts
  • fruit


Generally, arboreal mammals with gliding abilities such as Petinomys setosus can avoid terrestrial predators by remaining high in trees. Flying squirrels use canopies of trees as a method of concealment from predators. No predators are currently known for this species. (Hanski, 1998)

Ecosystem Roles

The impacts of Petinomys setosus have not been well researched, but many frugivorous squirrels contribute to seed planting and dispersal. (Thorington Jr, et al., 2012)

  • Ecosystem Impact
  • disperses seeds

Economic Importance for Humans: Positive

There are no known positive effects of Petinomys setosus on humans. (Jackson, 2012; Thorington Jr, et al., 2012; Wilson, et al., 2017)

Economic Importance for Humans: Negative

There are no known adverse effects of Petinomys setosus on humans. (Jackson, 2012; Thorington Jr, et al., 2012; Wilson, et al., 2017)

Conservation Status

Petinomys setosus is listed as Vulnerable by the IUCN Red List. (Clayton, 2020)


Ward Chapman (author), Portland State University, Ashley Contreras (author), Portland State University, Kathryn DeWilde (author), Portland State University, Tyler Mohrmann (author), Portland State University, Dana Sheets-Nichols (author), Portland State University, Tanya Dewey (editor), University of Michigan-Ann Arbor.



Referring to an animal that lives in trees; tree-climbing.

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.


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.


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 mainly eats seeds


An animal that eats mainly plants or parts of plants.


having the capacity to move from one place to another.


active during the night


found in the oriental region of the world. In other words, India and southeast Asia.

World Map


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.


reproduction that includes combining the genetic contribution of two individuals, a male and a female


uses touch to communicate


the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.


Clayton, E. 2020. "Temminck's Flying Squirrel" (On-line). IUCN Red List of Threatened Species. Accessed November 15, 2020 at

Hanski, I. 1998. Home ranges and habitat use in the declining flying squirrel. Wildlife Biology, 4(2): 33-46. Accessed November 16, 2020 at

Hayssen, V. 2008. Reproductive effort in squirrels. Journal of Mammalogy, 89(3): 582-606. Accessed November 16, 2020 at

Jackson, S. 2012. Gliding Mammals of the World. Australia: CSIRO Publishing.

Sanamxay, D., B. Douangboubpha, V. Xayaphet, P. Paphaphanh, T. Oshida, M. Motokawa. 2019. First record of Petinomys setosus (Rodentia: Sciuridae: Pteromyini) from Lao PDR. The Mammal Society of Japan, 44: 141-146. Accessed November 17, 2020 at https://doi:10.3106/ms2018-0053.

Thorington Jr, R., J. Koprowski, M. Steele, J. Whatton. 2012. Squirrels of the World. Baltimore: John Hopkins University Press.

Wilson, D., T. Lacher, R. Mittermeier, K. Aplin. 2017. Handbook of the Mammals of the World (Vol. 6). Barcelona: Lynx Edicions.