Plants and Animals Index

Squirrel Glider

Scientific name

Petaurus norfolcensis

Description

These marsupials are called Squirrel Gliders because of their dense bushy tails. The Squirrel Glider is very similar in appearance to the smaller Sugar Glider (Petaurus breviceps). However, Squirrel Gliders have a longer, more pointed face, longer and narrower ears and a bushier tail.

Squirrel Gliders weigh between 190gm and 300gm, with 230gm being an average adult weight. Their head and body length is 180mm to230mm with an average length of 210mm, and an average tail length of about 270mm.

Squirrel Gliders have blue/grey or brown/grey fur on their back and rich creamy white fur on their belly. They have a distinctive dark mid-dorsal stripe that extends from between their eyes to halfway down their back. Their tail is soft and bushy and is covered with grey to black fur, the end third of their tail is black.

Squirrel Gliders have long, sharp lower incisors. They possess a prehensile (grasping) tail, an opposable hallux (the first digit of the hind foot) and a long gliding membrane that extends from the outside of the forefoot to the ankle. It is one of the wrist-winged gliders of the Petaurus genus.

Squirrel Gliders are less vocal than Sugar Gliders. Squirrel Gliders produce deep and throaty gurgling chatters; soft, nasal grunts that sound somewhat like "n-when"; and repetitive, short gurgles.

The lifespan of Squirrel Gliders is four to six years, although in captivity they have been recorded as living longer - nearly 12 years.

Similar species are the Sugar Glider and the Mahogany Glider. Squirrel Gliders and Sugar Gliders sometimes live in the same areas. Where they do, Squirrel Gliders are usually the more abundant of the two species.

Habitat

The Squirrel Glider lives in dry sclerophyll forest and woodland throughout most of its range, but it occurs in some wet sclerophyll forests in Queensland. Individuals have also been recorded in a diverse range woodlands, including Blackbutt, Forest Red Gum and Red Bloodwood forests, Coastal Banksia heath-land and Grey Gum/Spotted Gum/ Grey Ironbark dry hardwood forests of the Central New South Wales Coast.

The Squirrel Glider needs abundant hollow-bearing trees and a mix of eucalypts, acacias and banksias. Within woodland at least one flora species should flower heavily in winter and one or more of the eucalypts should be a smooth-barked species. Squirrel Gliders prefer stands of trees with mixed tree species with a shrub or Acacia mid-storey.

The Squirrel Glider is widely though sparsely distributed along the east coast and immediate inland districts from western Victoria to north Queensland. They are found inland as far as the Grampians in Victoria and the Pilliga and the Coonabarabran areas of New South Wales. Suitable habitat can also be found in the River Red Gum Forests and Yellow Box woodlands of the Murray Darling Basin.

Behaviour

Squirrel Gliders are nocturnal, tree dwellers that use a membrane stretching between the fore and hind limbs to move from tree to tree. They are agile climbers and can glide for more than 50m in one movement.

Nightly movements are estimated as between 300m and 500m. Home ranges have been estimated at between 0.65 hectares and 8.55 hectares. Male Squirrel Gliders tend to range father than the females. The home range of a family group is likely to vary according to habitat quality and availability of food.

Squirrel Gliders nest in tree hollows where they construct a bowl-shaped nest lined with leaves.

Typical family groups consist of a mature male of over two years of age, one or more adult females, and the young of that season. In captivity, established family groups have been reported to attack newly introduced individuals and antagonistic behaviour has been displayed between communities.

Males have well developed scent glands on their foreheads which they use to mark their territory.

Squirrel Gliders are social and live in colonies. There can be up to nine individuals in one group and a male will mate with two or more females in a single breeding season.

Females can breed when they are between six and nine months of age. The breeding season occurs during June and July, with a gestation period that lasts around 16 to 21 days. They have a pouch in which they rear their young. The typical litter consists of one or two young. The young stay in their mother's pouch for approximately 70 days. They are fully furred at approximately 76 days and open their eyes at 85 days. The young will remain in the nest for another 40 to 50 days after emerging from the pouch. At the age of 110 to120 days, the young begin to venture out and forage with their mother. There is some evidence that females are capable of raising two litters in a year. Juveniles remain in their family range for approximately one year after emerging from the nest. Juvenile males are treated aggressively by the dominant male and must find a new range. Juvenile mortality following dispersal is high.

The Squirrel Glider is omnivorous. They forage in the upper and lower forest canopies and in the shrub understorey. They prefer smooth-barked eucalypts as these eucalypts have more hollows than rough-barked and support a greater diversity of invertebrates. The Squirrel Glider's diet varies with the seasons and their diet includes insects - especially the larvae of beetles, moths and butterflies, acacia gum, sap from certain eucalypts, nectar, pollen, and the green seeds of the Golden Wattle and casuarina. Nectar and pollen are the most important dietary items, but during winter when other food resources are scarce the Squirrel Glider may obtain its energy from the winter flowers of the Coastal Banksia, Red Ironbark, River Red Gum, Grey Ironbark, Spotted Gum, Forrest Red Gum and, in some areas, Blackbutt. Xanthorrhoea and mature acacias may also provide a valuable food source.

Status and Threats

Some of its main threats are land clearing, collection of firewood, clearing of woodlands and habitat fragmentation. Gliders' heavy reliance on tree hollows for shelter and protection places them in a position where they are susceptible to predators, in particular cats, foxes and owls. The loss of hollow-bearing trees, flowering understorey and mid-storey shrubs in forests impacts upon them. Also individuals can get caught in barbed wire fences while gliding.

The Squirrel Glider may be endangered in the southern part of its range, due to the mass clearing of woodland for agriculture and forest operations which decreases the abundance of tree hollows which it relies on for nesting sites.

The effects of logging, especially when compounded with exposure to drought and fire, have a negative impact on Glider species, reducing the habitability of an area. Deep gullies, unaffected by logging, were found to be crucial refuges for Gliders. It is recommended that these gullies be maintained and protected in order to conserve habitat for all species of Gliders.

References/Sources

Strahan, R. Mammals of Australia. Reed Books, Chatswood, NSW 1995.

Suckling, G. 1995. Squirrel Glider. Pp. 234-235 in R. Strahan, ed. Mammals of Australia. Washington , D.C. : Smithsonian Institution Press.

Encyclopedia of Australian Wildlife, Readers Digest, 2005.

The Australian Museum Complete Book of Australian Mammals, Angus & Robertson, 1983 ISBN 0 207 14454 0.

Flannery, T.F. Possums of the World,. GEO Productions/Australian Museum. 1994 ISBN 0 646 14389 1.

Menkhorst, P. and Knight, F. A Field Guide to the Mammals of Australia. 2nd Edition Oxford Uni Press, Melbourne. 2004 ISBN 0 19 555037 4.

Nowak, R.M Walker's Mammals of the World, 6th Edition, Volume 1. Baltimore : The Johns Hopkins University Press. 1999.

Smith, M. 1979. Observations on Growth of -Petaurus breviceps- and -P. norfolcensis- in Captivity. Australian Wildlife Research, 6: 141-150.

Lunney, D. 1987. Effects of Logging, Fire and Drought on Possums and Gliders in the Coastal Forests near Bega, N.S.W.. Australian Wildlife Research, 14: 263-274.

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