Greater glider

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Greater glider[1]
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Infraclass: Marsupialia
Order: Diprotodontia
Family: Pseudocheiridae
Subfamily:
Hemibelideinae
Genus: Petauroides
Thomas, 1888
Type species
Didelphis volans
, 1792
Species
  • P. armillatus
  • P. minor
  • P. volans
Greater glider range
Synonyms

Schoinobates

The greater gliders are three species of large gliding

Petauroides minor.[2]

These species are not closely related to the

Hemibelideinae.[1]

The greater gliders are

nocturnal and are solitary herbivores feeding almost exclusively on Eucalyptus leaves and buds.[3] Like their relative, the lemur-like ringtail, the southern greater glider is found in two forms: a sooty brown form and a grey-to-white form.[3] The central greater glider is instead silvery brown, while the northern greater glider is brownish-gray.[2]

The greater gliders are found in eucalypt forests from Mossman, Queensland, to Daylesford, Victoria.[3]

Taxonomy

Although the genus was formerly thought to be monotypic, there are now known to be three species in the genus:[2][4]

The species are known to

hybridize with one another near the edges of their ranges.[2]

Anatomy and physiology

Skeleton

The three species differ in their size, with the northern greater glider only growing to the size of a small ringtail possum, while the southern greater glider grows to the size of a house cat. The central greater glider is intermediate between these two.[5]

Greater gliders have a head and body 39 to 43 centimetres (15 to 17 in) long, with the females generally being larger than the males. Their body is covered with a shaggy coat of fur that increases their apparent size, and the tail is long and bushy, ranging from 44 to 53 centimetres (17 to 21 in). The head is short with a pointed muzzle and their large ears are fringed and backed with long fur.

Each side of the body bears

glides. This is in contrast to other gliding marsupials, such as the sugar glider, that have gliding membranes stretching from the wrists to the ankles.[6]

The feet have strongly recurved claws to grip onto bark or other surfaces. There are five toes on each foot. The first toe on the hind foot and the first two toes on the fore foot are opposable.[6]

The fur is soft and up to 60 millimetres (2.4 in) long. All three species have cream undersides and primarily differ in the coloration of their pelages. The

Victoria to 600 grams (1.3 lb) in the northern greater glider of north Queensland.[2]

Physiology

Heat management in the greater gliders is performed by licking extremities and the

arboreal habitats often having limited water accessibility.[7]

These gliders can digest low nutrient

caecum that contains a population of bacteria that ferment food residues that remain undigested in the small intestine.[9] For a population in a eucalypt forest near Maryborough, Queensland, it has been calculated that their daily energy intake is about 1130 kJ, which is provided by about 45 to 50 grams (0.099 to 0.110 lb) of dry matter daily.[10]

Mature females will give birth to a single joey each year which is typically born in late autumn or early winter. The underdeveloped offspring will then spend the next four months within the pouch of the mother to suckle and develop, and will remain within the security of the pouch until nine months of age.[11]

Distribution and habitat

Greater gliders are found in southern

Victorian central highlands.[15] It is usually tracked via spotlighting on transects (considered to underestimate the actual population size), radio tagging and owl-call playback.[16][17]

The greater gliders choose habitat based on several factors, the dominant factor being the presence of specific species of eucalypt. Distribution levels are higher in regions of montane forest containing manna gum (E. viminalis) and mountain gum (E. dalrympleana, E. obliqua). Furthermore, the presence of E. cypellocarpa appears to improve the quality of habitat for the greater gliders in forests dominated by E. obliqua. Another factor determining population density is elevation. Optimal levels are 845 m above sea level.[18] Within a forest of suitable habitat, they prefer overstorey basal areas in old-growth tree stands.[16]

Behaviour

morph
southern greater glider

The greater gliders are primarily

nocturnal, spending the night foraging in the highest parts of the forest canopy. During the day, they spend most of their time denning in hollowed trees, with each animal inhabiting up to twenty different dens within its home range. The dens are often lined with leaves and strips of bark.[6][19] This is why spotlighting has become a popular way of locating members of a population. When a strong light is directed at the eyes of a glider, the observer will see two bright red orbs reflecting back.[17]

Within forests, males and females will have home territories and set borders between other individuals. For males, home territory ranges from 1.4 to 4.1 hectares (3.5 to 10.1 acres) while that of females is only 1.3 to 3.0 hectares (3.2 to 7.4 acres). Although home ranges may overlap, the animals remain generally solitary outside of the breeding season, and only rarely interact. In large and small patches of forest, the home territories will respectively be larger and smaller.[20]

The gliding posture of the greater gliders is unique among marsupials. The forelimbs are folded so that the wrists are tucked under the chin, giving the patagium a triangular outline when outstretched. These animals regularly glide between high trees, and are able to use their tails to assist in steering. They avoid traveling along the ground whenever possible, and are slow and clumsy if forced to do so.[6]

Greater gliders do not make any loud sounds,[21] and are thought to communicate through scent marking. The animal's cloacal glands give it a generally musty smell.[22][23]

Ecology

Southern greater glider at Kioloa

Greater gliders subsist almost entirely on the young leaves and flower

lignocellulose which provides no nutrition. Overall, eucalypt leaves are a poor source of nutrients.[24]

Due to its nocturnal lifestyle, a natural predator of the gliders is the Powerful Owl (Ninox strenua). It hunts by concentrating in pockets within their relatively large home range until populations of prey are depleted to a level that causes the owl to shift hunting grounds.[25] Other predators include feral cats, introduced to Australia with the arrival of Europeans.[26]

Reproduction

The breeding season for greater gliders is relatively brief, lasting from February to May, with births occurring between April and June. Females have a relatively well-developed pouch, opening towards the forward part of the animal, and containing two teats.[6] Only a single young is born each year.[3]

At birth, the young weighs only around 0.27 grams (0.0095 oz), but it does not begin to leave the pouch for about four months, by which time it is already furred and well developed. After leaving the pouch, the mother may carry it about on her back until it is weaned at about seven months of age. The young are independent at nine months, and reach sexual maturity between 18 months and two years after birth.[6]

Greater gliders have been recorded living up to fifteen years.[27]

Northern greater glider (P. minor) at Ravenshoe, Queensland

Evolution

Although previously thought to be related to the

lemur-like ringtail possum, from which its ancestors diverged around 18 million years ago. In contrast, it diverged from the gliding possums much earlier, around 36 million years ago.[28] Fossils of greater gliders are known from the late Pleistocene onwards, and show that the animal was once more widespread and inhabited other areas including parts of South Australia.[6]

Conservation status

Greater gliders as a whole are listed as endangered nationally, in Queensland, New South Wales, the Australian Capital Territory and Victoria, under the EPBC Act, the Queensland Nature Conservation Act and Victorian Advisory List of Threatened Vertebrate Fauna.[29] Given the split into three species, and the uniquely threatened status of the southern species, this may need revision.[5]

References

  1. ^
    OCLC 62265494
    .
  2. ^
    PMID 33159131
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  3. ^
    ISBN 0-19-550870-X
    .
  4. doi:10.5281/zenodo.5175993
    , retrieved 2021-08-27
  5. ^ a b Reid, Sarah. "Australia's charismatic glider marsupial". www.bbc.com. Retrieved 2021-08-27.
  6. ^
    doi:10.1644/866.1
    .
  7. S2CID 36496032
    .
  8. S2CID 8460072
    .
  9. S2CID 87277073
    .
  10. doi:10.1071/ZO9900001
    .
  11. ^ "Greater Glider Petauroides volans in the Eurobodalla Local Government area - proposed endangered population listing". New South Wales Department of Environment and Climate Change. Retrieved 2008-05-05.
  12. ^ Wormington, K. R.; Lamb, D.; McCallum, H. I.; Moloney, D. J. (2002). "Habitat requirements for the conservation of arboreal marsupials in dry sclerophyll forests of southeast Queensland, Australia". Forest Science. 48 (2): 217–227.
  13. doi:10.1046/j.1471-8286.2002.00148.x
    .
  14. PMID 11310891
    .
  15. doi:10.1016/S0006-3207(00)00144-0
    .
  16. ^
    doi:10.1016/S0006-3207(00)00144-0
    .
  17. ^
    doi:10.1071/WR00002
    .
  18. doi:10.1071/PC000018
    .
  19. doi:10.1071/WR06063
    .
  20. doi:10.1071/WR02110
    .
  21. S2CID 254726103
    .
  22. ^
    doi:10.1071/WR9960401. Archived from the original
    (PDF) on 2011-03-10. Retrieved 2011-08-17.
  23. ^ Pockets Pets Team. "Pocket Pets". GRE, Inc. Retrieved 6 November 2012.
  24. doi:10.1071/WR9900285
    .
  25. doi:10.1111/j.1442-9993.1988.tb00992.x
    .
  26. ^ "Greater Glider". Gliders in the Spotlight. Wildlife Preservation Society of Queensland. Archived from the original on 2008-07-21. Retrieved 2008-05-05.
  27. JSTOR 1383054
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  28. doi:10.1071/ZO9920423
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  29. ^ "Petauroides volans — Greater Glider (southern and central)". Species Profile and Threats Database. 2024. Retrieved 31 January 2024.

Bibliography

External links

Wikimedia Commons has media related to Petauroides volans.
Wikispecies has information related to Petauroides volans.
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