Acrobates pygmaeusfeathertail glider

Geographic Range

Restricted to mainland Austrailia, but has a wide distribution through most of the open and closed forests of eastern and south-eastern Austraila from Cape York to the southeastern corner of South Austrailia. Also found in river redgum forests associated with inland rivers, particularly the Murray River (Ward, 1990)

Habitat

Acrobates pygmaeus is found in a wide range of habitats. It has been observed foraging on the ground, in large trees and bushes and in tall grasses. Feathertailed Gliders have been observed foraging at hieghts from ground level to 40 meters above the ground. Height of foraging depends on species of tree and abundance of food, but it is independent of season (Goldingay and Kavanagh, 1995).

Physical Description

Range in weight of males is similar to that of females, but in most cases the males actually weighed more. Head and body length ranges from 65-80mm, and tail length ranges from 70-80mm. Most notable characteristic of A. pygmaeus is the feather-like tail, which no other mammal has. It has molars suggestive of an insectivore, but also a brush-tipped tongue typical of a nectar-feeder. Its large forwardly directed eyes are for nocturnal binocular vision, and it has large serrated pads on each toe, which aid in adhesion to smooth surfaces. A. pygmaeus has a somewhat prehensile tail that provides grip on twigs and small branches.

  • Average mass
    13 g
    0.46 oz
    AnAge
  • Average basal metabolic rate
    0.084 W
    AnAge

Reproduction

In southeastern Australia the species breeds from July to January and females usually produce two litters within this time. The second litter is conceived at a post-partum oestrus and undergoes a period of embryonic diapause. Males exhibit enlarged testes and epididymides at the start of the breeding season, but show a decline during the season. There may be four or more pouch young but the number seldom exceeds the number of teats, which is four. Pouch life lasts about 9 weeks, which is long for a marsupial of this size, but the stage of development is similar to other marsupials at the time of pouch exit. On average, about one young is lost from each litter during lactation. Reduction in litter sizes may be a result of the female matching cost of lactation with levels of resources available. At the time of weaning, individuals are large and may continue to associate with their mothers, however, 90% of both sexes disappear from the population, either through dispersal or mortality, before they reach maturity (Ward, 1990).

  • Key Reproductive Features
  • gonochoric/gonochoristic/dioecious (sexes separate)
  • sexual
  • Average number of offspring
    3
    AnAge
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    240 days
    AnAge
  • Average age at sexual or reproductive maturity (male)
    Sex: male
    365 days
    AnAge

Lifespan/Longevity

Behavior

The Pygmy Glider is normally active at night except when rearing young. Then the female is seen to emerge to feed or drink during the late afternoon. Groups of A. pygmaeus have been observed in practically any available enclosed space, from hollow tree trunks to telephone interchange boxes to bird nests or possum dreys. They form spherical nests (dreys) of vegatation, usually eucalypt leaves, bark and tree-fern fiber (Strahan, 1983). They have been found in groups of up to 20 individuals, but these are not considered stable associations. It is believed that communication between mother and young is through a number of high-frequency sounds and marking with urine. Feeding in groups is commonly observed in captivity, but it has been seen in the wild only once (Strahan, 1983). A. pygmaeus undergoes multiday torpor bouts, lowering its body temperature to about 2 degrees Celcius. This is different from deep hibernation. There is no prehibernation fattening and it seems that prolonged torpor is used only in emergency situations (Jones and Geiser, 1992).

Communication and Perception

Food Habits

Most of the feeding behavior of this species takes place in eucalypts. They search under loose bark and glean foliage. The searching of loose bark suggests that the animal feeds on honeydew and arthropods, while the foliage gleaning is suggestive of feeding on manna, honeydew, lerps and arthropods. Nectar feeding has been seen (Goldingay and Kavanagh, 1995) but is said to only rarely occur.

Conservation Status

Acrobates pygmaeus is said to be common in its geographic range and individual habitats.

Other Comments

It is said to be that the Feathertail Glider is likely to be among the most sensitive of the Australian mammals to habitat alterations associated with timber harvest due to the arboreal lifestyle of these marsupials.

Contributors

Adam Shiroff (author), University of Michigan-Ann Arbor.

Glossary

Australian

Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

World Map

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.

chemical

uses smells or other chemicals to communicate

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.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

motile

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.

sexual

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

tactile

uses touch to communicate

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5? N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

References

Goldingay, R.L. and Kavanagh, R.P. 1995. Foraging Behavior and Habitat Use of the Feathertail Glider (Acrobates pygmaeus) at Waratah Creek, New South Wales. Wildlife Research 22:457-70

Jones, C.J. and Geiser, F. 1992. Prolonged and daily torpor in the feathertail glider, Acrobates pymaeus (Marsupialia: Acrobatidae) Journal of Zoology, London 227:101-108.

Lawlor, T.E. 1979. Handbook to the Orders and Families of Living Mammals (Second Edition) Mad River Press.

Strahan, R. 1983. The Mammals of Australia Angus & Robertson Publishers.

Vaughan, T.A. 1986. Mammology Saunders College Publishing.

Ward, S.J. 1990. Life History of the Feathertail Glider, Acrobates pygmaues (Acrobatidae: Marsupialia) in South-eastern Australia. Australian Journal of Zoology 38:503-17.