Feathertail glider (Acrobates pygmaeus)

Description

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Feathertail glider fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
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Feathertail glider description

Found only in Australia, the feathertail glider (Acrobates pygmaeus) is the smallest of the gliding possums and one of the smallest gliding mammals in the world ^{(2) (3) (4)}. This tiny marsupial has a narrow gliding membrane, known as a ‘patagium’, which consists of a fold of skin that stretches between the limbs ^{(3) (4) (5)} and which is retracted when not in use ⁽²⁾.

Compared to that of other gliding possums, the patagium of the feathertail glider has a relatively small surface area, but its effective size is increased by a fringe of hairs along its edges ^{(2) (5)}. The membrane extends only from the elbow to the knee, and the feathertail glider’s limbs are not elongated to support it ^{(2) (4) (5)}. The arrangement of muscles within the membrane also differs from that of other gliding possums, indicating that the feathertail glider’s ability to glide evolved independently from other species ^{(4) (5) (6)}.

Another unusual feature of the feathertail glider, from which it receives its common name, is the feather-like arrangement of stiff hairs along its flattened tail ^{(2) (3) (4) (6)}. This fringe of hairs spreads from each side of the tail to a width of about eight millimetres. The tip of the tail lacks fur underneath, and is somewhat prehensile ⁽³⁾.

The feathertail glider’s fur is soft and silky. The upperparts of its body are greyish-brown, while the underparts and the inner sides of the limbs are white. The tail is light brown, with a slightly paler underside. The ears of the feathertail glider are sparsely haired, and have tufts of fur at the base ⁽³⁾.

Also known as

flying mouse, pygmy feathertail glider, pygmy glider, pygmy gliding possum, pygmy phalanger.

Size

Head-body length: 6.5 - 8 cm ^{(2) (3)}

Tail length: 7 - 8 cm ^{(2) (3)}

Weight

10 - 15 g ⁽²⁾

Feathertail glider biology

One of the most remarkable features of the feathertail glider is its ability to glide with the aid of its gliding membrane. This gliding ability is further enhanced by the feather-like arrangement of hairs on the tail ^{(3) (6)}. The tail not only provides an increased surface area for gliding, but also serves as a rudder, helping the feathertail glider to steer and brake ⁽⁶⁾.

The feathertail glider can perform quite impressive aerial acrobatic feats, as suggested by its scientific name, Acrobates pygmaeus, which means ‘pygmy acrobat’ ^{(2) (3)}. Although it typically glides in a direct path, the feathertail glider can also spiral around a tree trunk before it lands ⁽⁶⁾. Despite its small size, this species can glide for distances of over 30 metres ⁽²⁾.

The ability to glide means that the feathertail glider does not need to descend to the ground when foraging, which would expose it to a higher risk of predation. It also enables the feathertail glider to escape predators by gliding away, and makes it more difficult for predators to track it since it does not create continuous scent trails when moving about. Gliding is also a more efficient form of locomotion than having to climb down, cross the ground and climb up again into the trees ^{(4) (6)}.

As well as being able to glide, the feathertail glider is a fast, agile climber and is well adapted for life in the trees. Its prehensile tail gives good grip ^{(5) (6)}, and its large eyes help it to navigate about its complex three-dimensional environment ⁽⁶⁾. In addition, the tips of its toes are expanded and have deeply ridged grooves which provide traction and grip while climbing smooth Eucalyptus trees ^{(3) (4) (5) (6)}. These ‘suction pad’ toes also assist when landing after a glide, and their gripping ability is further enhanced by sweat glands at the base of the grooves, which moisten the pads. The amazing adhesive gripping ability of the feathertail glider is demonstrated by the fact that it is able to climb up vertical panes of glass ^{(4) (5) (6)}.

The feathertail glider is largely nocturnal, emerging from its nesting hollow at dusk to forage ^{(2) (3) (5)}. The nest of this species is a spherical construction of leaves and bark fibres, built in a small tree hole, or sometimes in an artificial nesting box or even a telephone junction box ^{(3) (4) (5) (8)}. A social species, the feathertail glider may sometimes nest together in groups of up to 30 individuals ⁽²⁾, although groups of 2 to 5 may be more common ⁽³⁾. Large aggregations of up to 40 feathertail gliders have also been seen feeding together at flowering trees ⁽⁵⁾.

As an adaptation to conserve energy when it is cold, the feathertail glider may undergo periods of torpor, during which its body temperature and metabolic rate drop ^{(2) (3) (4) (5)}. It also saves energy and reduces heat loss by curling into a ball, wrapping its tail around itself, and by huddling together in groups ⁽²⁾.

In some parts of its range, the feathertail glider can breed at any time of year, while in more southern areas births tend to be more seasonal, usually occurring between July and January ^{(2) (3) (4) (5)}. The female feathertail glider may give birth to up to four young at a time, although typically only two survive to weaning ^{(3) (4)}. Most females have up to two or sometimes three litters per year ^{(2) (3) (4) (5)}.

As in other marsupials, the newborn feathertail gliders are tiny and are born at a very early stage of development, with their eyes closed and lacking fur ⁽⁴⁾. The young are suckled within the female’s pouch, where they remain for about 60 to 65 days, after which they are left in the nest ^{(3) (4)}. Once well furred, the young may also ride on the female’s back ⁽³⁾.

An interesting aspect of the feathertail glider’s reproduction is that it is capable of embryonic diapause ^{(2) (3) (4)}. Almost immediately after giving birth, the female feathertail glider will mate again, but the new embryos will become dormant until the current young in the pouch are weaned, at about 100 days old ^{(3) (4) (5)}. This means that a second litter can be born almost immediately after the first is weaned ⁽³⁾.

After weaning, the young feathertail gliders remain with the female while the second litter is raised ^{(3) (4)}. Female feathertail gliders usually reach sexual maturity at about 8 months, and males by about 12 to 18 months ⁽³⁾. This species has been known to live to at least seven years old in captivity ⁽³⁾, although the usual lifespan is closer to two to three years ⁽⁴⁾.

The diet of the feathertail glider comprises insects, fruit, nectar, pollen, fungi and seeds, as well as sap, gum and honeydew ^{(2) (3) (4)}. Pollen provides the feathertail glider with a major source of protein, and it has a long, brush-tipped tongue as an adaptation to extracting pollen and nectar ^{(2) (4) (5)}. The feathertail glider is likely to be important in pollinating native plants ⁽⁵⁾.

Feathertail glider range

The feathertail glider is endemic to Australia, where it ranges throughout much of the east and southeast of the country ⁽¹⁾, from Cape York in Queensland to south-eastern South Australia ^{(2) (3) (5)}. It is the only Acrobatidae species to occur in Australia, with the other, the feather-tailed possum (Distoechurus pennatus), being confined to New Guinea ⁽⁴⁾.

This species is believed to be common in certain parts of its range, such as in northeast Queensland, but is rarer in more southern areas ⁽¹⁾. The feathertail glider also occurs on Fraser Island, off the southern coast of Queensland ⁽¹⁾.

Feathertail glider habitat

The feathertail glider inhabits a range of habitat types, from tall open forest and sclerophyll forest to woodland ^{(1) (2) (3) (5)}. It appears to be more common in wet and old-growth forest than in dry or regenerating forest ^{(1) (7)}.

The feathertail glider is also able to occupy the fringes of suburban areas ⁽¹⁾.

Feathertail glider status

The feathertail glider is classified as Least Concern (LC) on the IUCN Red List ⁽¹⁾.

Feathertail glider threats

The feathertail glider is relatively common and widespread, and is not currently considered to be at risk of extinction ⁽¹⁾. However, it may be locally threatened by the logging of stands of mature forest ⁽¹⁾ and by a reduction in the availability of trees with suitable nesting hollows ⁽²⁾.

The feathertail glider may also be affected by predation by cats and foxes ^{(1) (3)}, and cats have been known to destroy entire colonies of this species ⁽²⁾.

Feathertail glider conservation

Accurate estimations of the feathertail glider’s population numbers can be difficult to make as it is not always easy to detect this small, fast, nocturnal animal ^{(2) (5)}. However, its use of artificial nests and telephone junction boxes means that information on other aspects of its biology can be relatively easy to obtain ⁽⁵⁾.

There are not known to be any specific conservation measures currently in place for the feathertail glider, but it is known to occur in a number of protected areas ⁽¹⁾. Land management practices need to ensure that suitable habitat, with good supplies of nectar and pollen, vegetation cover and nesting sites, is maintained. Corridors of suitable habitat linking protected areas would also help juvenile feathertail gliders to disperse and aid interbreeding between populations ⁽⁵⁾.

Find out more

Find out more about the feathertail glider and related species:

• Turner, V. and McKay, G.M. (1989) Burramyidae. In: Walton, D.W. and Richardson, B.J. (Eds.) Fauna of Australia. Volume 1B: Mammalia. Australian Government Publishing Service, Canberra. Available at:
  http://www.environment.gov.au/biodiversity/abrs/publications/fauna-of-australia/pubs/volume1b/27-ind.pdf
• Lindenmayer, D. (2002) Gliders of Australia: A Natural History. UNSW Press, Sydney.

More information on conservation in Australia:

• Australian Wildlife Conservancy:
  http://www.australianwildlife.org/

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Glossary

Embryonic diapause

Also known as delayed implantation. A reproductive strategy found in some mammals, such as some marsupial, rodent, bear and mustelid species, in which the embryo does not immediately implant in the uterus, but remains dormant, only implanting and continuing development when conditions are favourable. This strategy allows the female to give birth when survival of the offspring is more likely, such as when environmental conditions are more favourable or the previous offspring has been weaned.

Endemic

A species or taxonomic group that is only found in one particular country or geographic area.

Gland

An organ that makes and secretes substances used by the body.

Honeydew

A sugar-rich secretion produced by aphids and some scale insects that feed on plant sap.

Marsupial

A diverse group of mammals characterised by their reproduction, in which gestation is very short, and the female typically has a pouch (marsupium) in which the young are raised. When born, the tiny young crawls to the mother’s teats, where it attaches and stays for a variable amount of time, whilst it continues to develop. Marsupials also differ from placental mammals in their dentition.

Metabolic rate

The speed at which an animal uses energy; the amount of energy it expends in a given time.

Nocturnal

Active at night.

Pollinate

To transfer pollen grains from the stamen (male part of a flower) to the stigma (female part of a flower) of a flowering plant. This usually leads to fertilisation, the development of seeds and, eventually, a new plant.

Prehensile

Capable of grasping.

Sclerophyll

A type of vegetation with hard, thick-skinned leaves; for example, eucalypts and acacias.

Torpor

A sleep-like state in which the body processes slow to a fraction of their normal rate.

References

1. IUCN Red List (July, 2011)
   http://www.iucnredlist.org/
2. Lindenmayer, D. (2002) Gliders of Australia: A Natural History. UNSW Press, Sydney.
3. Nowak, R.M. (1991) Walker’s Mammals of the World. The Johns Hopkins University Press, Baltimore and London.
4. Tyndale-Biscoe, H. (2005) Life of Marsupials. CSIRO Publishing, Collingwood, Victoria.
5. Turner, V. and McKay, G.M. (1989) Burramyidae. In: Walton, D.W. and Richardson, B.J. (Eds.) Fauna of Australia. Volume 1B: Mammalia. Australian Government Publishing Service, Canberra. Available at:
   http://www.environment.gov.au/biodiversity/abrs/publications/fauna-of-australia/pubs/volume1b/27-ind.pdf
6. Jones, C. and Parish, S. (2006) Field Guide to Australian Mammals. Steve Parish Publishing, Archerfield, Queensland.
7. Menkhorst, P. and Knight, F. (2001) A Field Guide to the Mammals of Australia. Oxford University Press, Oxford.
8. Fanning, F.D. (1980) Nests of the feathertail glider, Acrobates pygmaeus (Burramyidae: Marsupialia) from Sydney, New South Wales. Australian Mammalogy, 3: 55-56.