Petaurillus hoseiHose's pygmy flying squirrel

Geographic Range

Petaurillus hosei (Hose’s Pygmy flying squirrel) is endemic to the eastern coast of Sarawak, on the northwestern side of Borneo. (Wilson and Reeder, 1993)


There was not any specific information found on the habitat of P. hosei but, as are most flying squirrels, Hose's pygmy flying squirrels are highly arboreal. These squirrels have only been found in lowland forest types and are reported to use tree cavities as nest holes. (Nowak, 1999)

Physical Description

Species in the genus Petaurillus are the smallest of the flying squirrels, with head and body length ranging from 68 to 89 mm and tail length from 62 to 98 mm. Hose's pygmy flying squirrels have large eyes and ears. The body is similar to that of all flying squirrels, with a flat hairy tail and a gliding membrane that extends between the fore and hindlimbs, called a patagium. Patagia increase the surface area of these squirrels, enabling gliding. A cartilaginous extension of the wrist bones assists in spreading the patagia. Flying squirrels have five digits on their hind limbs and four digits on their forelimbs, each digit has a long claw at the end, which assists in climbing trees. Hose's pygmy flying squirrels have dark dorsal fur and white ventral surfaces. They have a white spot behind each ear and pale or buffy colored cheeks. The tail is brown with a white tip. The teeth are not complex. (Eisenberg, 1989; MacDonald, 1984; Nowak, 1999; Redford and Eisenberg, 1992; Wilson and Reeder, 1993)

  • Range mass
    68 to 89 g
    2.40 to 3.14 oz
  • Range length
    62 to 98 mm
    2.44 to 3.86 in


The mating system of P. hosei is unknown. Mating systems in flying squirrels are generally not well understood, but it is likely that males and females do not associate beyond a single breeding season. (MacDonald, 1984)

Little is known about reproduction in Hose's pygmy flying squirrels. A close relative, Selangor pygmy flying squirrels (P. kinlochii), has a reported litter size of two. Females have 4 mammae, indicating a maximum litter size of 4. In other flying squirrels, breeding can occur multiple times during the breeding season, young are weaned within several months of birth, and reproductive maturity is acheived within a year of birth. Because Hose's pygmy flying squirrels live in lowland, tropical habitats, they may breed throughout the year.

  • Breeding interval
    Breeding intervals are not known, but breeding may occur multiple times throughout the year.
  • Breeding season
    Seasonality of breeding is not known.
  • Range number of offspring
    4 (high)

Hose's pygmy flying squirrel females nurse and care for their young, as do all female mammals. They may be the sole caretakers of their young. Young are probably left in a nest in a tree cavity until they are weaned and become independent. (Nowak, 1999)

  • Parental Investment
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female


Information on the life span of P. hosei was not found but other, small flying squirrels may live to 5 to 6 years old in the wild. Because of their body size, Hose's pygmy flying squirrels may have relatively short lifespans. (MacDonald, 1984; Nowak, 1999)


Little is known about behavior in Hose's pygmy flying squirrels. Flying squirrels, in general, are nocturnal animals that mostly stay in the trees. They travel by scampering along branches and gliding between trees. Four individual Hose's pygmy flying squirrels were reported to be found in the same nest cavity, suggesting that there may be some sociality or that the individuals were a family group. These squirrels are nocturnal (Nowak, 1999)

Home Range

The home range is unknown.

Communication and Perception

Like other aspects of the natural history of Hose's pygmy flying squirrels, there is nothing known about social interactions. Other flying squirrels use sounds, chemical cues, and visual cues, such as movements with the tail, to communicate. These flying squirrels, like others, are likely to have excellent night vision and hearing that they use to navigate and avoid predation at night. They may have a keen sense of smell to locate food items and to communicate. (MacDonald, 1984)

Food Habits

No information was found on the diet of Hose’s pygmy flying squirrels. In general, flying squirrels eat seeds, fruits, and fungi. They may also take insects, bird eggs and nestlings, and other small animals as they find them. (MacDonald, 1984)


Predators of Hose's pygmy flying squirrels are unknown. Likely predators of these small, nocturnal, arboreal mammals are nocturnal raptors, such as owls and arboreal snakes. (MacDonald, 1984)

Ecosystem Roles

Because Hose's pygmy flying squirrels are likely to eat fruits, seeds, and fungi, they are likely to be important in dispersing tree seeds and fungal spores in their lowland, forest ecosystems.

  • Ecosystem Impact
  • disperses seeds

Economic Importance for Humans: Positive

Hose's pygmy flying squirrels, like other flying squirrels, are likely to impact seed and fungal spore dispersal in their native habitats through their feeding habits.

Economic Importance for Humans: Negative

There are no known adverse effects of P. hosei on humans.

Conservation Status

According to the IUCN’s red list of threatened species, P. hosei is listed as low risk, least concern. (Baillie, 2006)


Tanya Dewey (author, editor), Animal Diversity Web.



uses sound to communicate


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.

island endemic

animals that live only on an island or set of islands.


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.

native range

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.

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.


remains in the same area


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


uses touch to communicate


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.


Baillie, J. 2006. "IUCN" (On-line). 2006 IUCN Redlist of Threatened Species. Accessed November 30, 2006 at

Eisenberg, J. 1989. The Mammals of the Neotropics, The Northern Neotropics. Chicago and London: The University of Chicago Press.

MacDonald, D. 1984. The Encyclopedia of Mammals. New York: Facts On File.

Nowak, R. 1999. Walker's Mammals of the World. Baltimore: The John Hopkins University Press.

Redford, K., J. Eisenberg. 1992. Mammals of the Neotropics, The Southern Cone. Chicago and London: The University of Chicago Press.

Wilson, D., D. Reeder. 1993. Mammal Species of The World. Washington District of Columbia: Smithsonian Institute.