Greater Glider
Encyclopedia
The Greater Glider is a small gliding marsupial found in Australia
. It is not closely related to the Petaurus
group of gliding marsupials but instead to the Lemur-like Ringtail Possum
(Hemibelideus lemuroides), with which it shares the subfamily Hemibelideinae.
The Greater Glider is nocturnal and is a solitary herbivore
feeding almost exclusively on Eucalyptus
leaves and buds. Like its relative the Lemur-like Ringtail, the Greater Glider is found in two forms: a sooty brown form, or a grey-to-white form.
The Greater Glider is found in eucalypt forest from Mossman
, Queensland
, to Daylesford
, Victoria.
stretching between the elbow and the ankle, that give the animal the ability to perform controlled 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.
The feet have strongly recurved claws to grip onto bark or other surfaces. There are five toes on each foot, with the first first toe on the hind foot, and the first two toes on the fore foot, being opposable.
The fur is soft and up to 60 millimetres (2.4 in) long; the colour is variable within the same populations, ranging from white to brown and charcoal. Body mass varies clinally from about 1600 grams (3.5 lb) in southern Victoria
to about 600 grams (1.3 lb) in north Queensland
.
being the main method of the cooling. Furthermore, the glider can use its gliding membranes to reduce heat loss by increasing the layer of insulation at the skin surface. However, the Greater Glider is not well equipped to handle high ambient temperatures, as it inefficiently uses water for evaporation via salivation even though arboreal habitats are often limited in water accessibility.
The Greater Glider can digest low nutrient foliage, specifically eucalypt
leaf matter, which contains a variety of phenolic
and terpenoid
compounds and a high concentration of lignified fibre. Animals can digest about 50-60% of the leaf during its passage through the gut The gut has a specialized caecum that is contains a poulation of bacteria that ferment food residues that remain undigested in the small intestine. . 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 g (0.0992080179831949 to 0.110231131092439 lb) of dry matter daily.
Mature females will give birth to a single progeny, each year which is typically born in late autumn or early winter. The underdeveloped offspring will then spend the next 4 months within the pouch of the mother to suckle and develop. It will remain within the security of the pouch until about 9 months of age.
, eastern Australia, southeastern New South Wales
, and the montane forests of the Victorian central highlands. The Greater Glider is usually tracked via spotlighting on transects (considered to underestimate the actual population size), radio tagging and owl-call playback.
There are two recognised subspecies:
The Greater Glider chooses habitat based on several factors. A large factor determining habitat choice is 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 Glider in forests dominated by E. obliqua. Another factor determining population density is elevation. Optimal levels are 845 m above sea level. Within a forest of suitable habitat, they prefer overstorey basal areas in old-growth tree stands.
The Greater Glider is primarily nocturnal, spending the night foraging
in the highest parts of the forest canopy. During the day, it spends most of its time denning in hollowed trees, with each animal using up to twenty different dens within its home range. The dens are often lined with leaves and strips of bark. 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.
Within forests, males and females will have home territories and set borders between other members. For males, home territory ranges from 1.4 to 4.1 ha (3.5 to 10.1 acre) while that of females is only 1.3 to 3 ha (3.2 to 7.4 acre). 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.
The gliding posture of the Greater Glider 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. The animal regularly glides between high trees, and is able to use the tail to assist in steering. They avoid travelling along the ground whenever possible, and are slow and clumsy if forced to do so.
Greater Gliders do not make any loud sounds, and probably communicate through scent marking. The animal's cloaca
l glands give it a generally musty smell.
s of select eucalypt species, especially Eucalyptus radiata
, Eucalyptus viminalis, and Eucalyptus acmenoides
. Young leaves are preferred because they have higher concentration of nitrogen
and lower concentration of lignocellulose (acid-detergent fibre). Overall, the eucalypt leaves are a poor source of nutrients.
Because of its night time activities, a natural predator on the glider 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. Other predators include feral cats, which are not native to Australia, being introduced with the arrival of Europeans.
, opening towards the forward part of the animal, and containing two teats. Only a single young is born each year.
At birth, the young weighs only around 0.27 gram (0.00952396976838023 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.
Greater gliders have been recorded as living for up to fifteen years.
, the Greater Glider is now known to be most closely related to the ringtail possum
s, and especially 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. Fossils of Greater Gliders are known from the late Pleistocene
onwards, and show that the animal was once more widespread, also being found in at least some areas of South Australia
.
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
. It is not closely related to the Petaurus
Petaurus
The genus Petaurus contains flying phalangers or wrist-winged gliders, a group of arboreal marsupials. There are six species, Sugar Glider, Squirrel Glider, Mahogany Glider, Northern Glider, Yellow-bellied Glider and Biak Glider, and are native to Australia or New Guinea.Flying phalangers are...
group of gliding marsupials but instead to the Lemur-like Ringtail Possum
Lemur-like Ringtail Possum
The Lemur-like Ringtail Possum , also known as the Lemuroid Ringtail Possum or the Brushy-Tailed Ringtail, is one of the most singular members of the ringtail possum group...
(Hemibelideus lemuroides), with which it shares the subfamily Hemibelideinae.
The Greater Glider is nocturnal and is a solitary herbivore
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...
feeding almost exclusively on Eucalyptus
Eucalyptus
Eucalyptus is a diverse genus of flowering trees in the myrtle family, Myrtaceae. Members of the genus dominate the tree flora of Australia...
leaves and buds. Like its relative the Lemur-like Ringtail, the Greater Glider is found in two forms: a sooty brown form, or a grey-to-white form.
The Greater Glider is found in eucalypt forest from Mossman
Mossman, Queensland
For the collection of Horsedrawn Carriages see Mossman CollectionMossman is a town in Far North Queensland, Australia, on the Mossman River...
, Queensland
Queensland
Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
, to Daylesford
Daylesford, Victoria
Daylesford is a town located in the Shire of Hepburn, Victoria, Australia. It is a former goldmining town about 115 kilometres north-west of Melbourne, in the foothills of the Great Dividing Range. At the 2006 census, Daylesford had a population of 3,073...
, Victoria.
Anatomy and physiology
Greater Gliders have a head and body about 39 to 43 cm (15.4 to 16.9 in) long, with the females being generally 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 cm (17.3 to 20.9 in). The head is short, but with a pointed muzzle, and large ears fringed and backed with long fur. Each side of the body bears membranesPatagium
*In bats, the skin forming the surface of the wing. It is an extension of the skin of the abdomen that runs to the tip of each digit, uniting the forelimb with the body.*The patagium of a bat has four distinct parts:...
stretching between the elbow and the ankle, that give the animal the ability to perform controlled glides. This is in contrast to other gliding marsupials (such as the Sugar Glider
Sugar Glider
The sugar glider is a small gliding possum originating from the marsupial family.The sugar glider is native to eastern and northern mainland Australia and is also native to New Guinea and the Bismarck Archipelago.- Habitat :Sugar gliders can be found all throughout the northern and eastern parts of...
) that have gliding membranes stretching from the wrists to the ankles.
The feet have strongly recurved claws to grip onto bark or other surfaces. There are five toes on each foot, with the first first toe on the hind foot, and the first two toes on the fore foot, being opposable.
The fur is soft and up to 60 millimetres (2.4 in) long; the colour is variable within the same populations, ranging from white to brown and charcoal. Body mass varies clinally from about 1600 grams (3.5 lb) in southern Victoria
Victoria (Australia)
Victoria is the second most populous state in Australia. Geographically the smallest mainland state, Victoria is bordered by New South Wales, South Australia, and Tasmania on Boundary Islet to the north, west and south respectively....
to about 600 grams (1.3 lb) in north Queensland
Queensland
Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
.
Physiology
Heat management in the Greater Glider is performed by licking extremities and the ventral body surface, with direct evaporationEvaporation
Evaporation is a type of vaporization of a liquid that occurs only on the surface of a liquid. The other type of vaporization is boiling, which, instead, occurs on the entire mass of the liquid....
being the main method of the cooling. Furthermore, the glider can use its gliding membranes to reduce heat loss by increasing the layer of insulation at the skin surface. However, the Greater Glider is not well equipped to handle high ambient temperatures, as it inefficiently uses water for evaporation via salivation even though arboreal habitats are often limited in water accessibility.
The Greater Glider can digest low nutrient foliage, specifically eucalypt
Eucalypt
Eucalypts are woody plants belonging to three closely related genera:Eucalyptus, Corymbia and Angophora.In 1995 new evidence, largely genetic, indicated that some prominent Eucalyptus species were actually more closely related to Angophora than to the other eucalypts; they were split off into the...
leaf matter, which contains a variety of phenolic
Polyphenol
Polyphenols are a structural class of natural, synthetic, and semisynthetic organic chemicals characterized by the presence of large multiples of phenol structural units...
and terpenoid
Terpenoid
The terpenoids , sometimes called isoprenoids, are a large and diverse class of naturally occurring organic chemicals similar to terpenes, derived from five-carbon isoprene units assembled and modified in thousands of ways. Most are multicyclic structures that differ from one another not only in...
compounds and a high concentration of lignified fibre. Animals can digest about 50-60% of the leaf during its passage through the gut The gut has a specialized caecum that is contains a poulation of bacteria that ferment food residues that remain undigested in the small intestine. . For a population in a eucalypt
Eucalypt
Eucalypts are woody plants belonging to three closely related genera:Eucalyptus, Corymbia and Angophora.In 1995 new evidence, largely genetic, indicated that some prominent Eucalyptus species were actually more closely related to Angophora than to the other eucalypts; they were split off into the...
forest near Maryborough, Queensland
Maryborough, Queensland
Maryborough is a city located on the Mary River in South East Queensland, Australia, approximately north of the state capital, Brisbane. The city is serviced by the Bruce Highway, and has a population of approximately 22,000 . It is closely tied to its neighbour city Hervey Bay which is...
, it has been calculated that their daily energy intake is about 1130 kJ, which is provided by about 45 to 50 g (0.0992080179831949 to 0.110231131092439 lb) of dry matter daily.
Mature females will give birth to a single progeny, each year which is typically born in late autumn or early winter. The underdeveloped offspring will then spend the next 4 months within the pouch of the mother to suckle and develop. It will remain within the security of the pouch until about 9 months of age.
Distribution and habitat
The Greater Glider is found in southern QueenslandQueensland
Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
, eastern Australia, southeastern New South Wales
New South Wales
New South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...
, and the montane forests of the Victorian central highlands. The Greater Glider is usually tracked via spotlighting on transects (considered to underestimate the actual population size), radio tagging and owl-call playback.
There are two recognised subspecies:
- Petauroides volans volans - temperate and subtropical Victoria, NSW, and Queensland
- Petauroides volans minor - tropical Queensland
The Greater Glider chooses habitat based on several factors. A large factor determining habitat choice is 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
Eucalyptus dalrympleana
White Mountain Gum is a tree from the genus Eucalyptus. It is a tall tree, growing up to 50m in favourable conditions but is small and irregular in poor soils. The bark is smooth, darkening to salmon pink or light brown before flaking off to reveal new pure white bark...
, E. obliqua
Eucalyptus obliqua
Eucalyptus obliqua, commonly known as Australian Oak, Brown Top, Brown Top Stringbark, Messmate, Messmate Stringybark, Stringybark and Tasmanian Oak, is a hardwood tree native to south-eastern Australia....
). Furthermore, the presence of E. cypellocarpa
Eucalyptus cypellocarpa
Mountain Grey Gum also known as the Mountain Gum, Monkey Gum or Spotted Mountain Grey Gum, is a straight, smooth barked forest tree. Often seen around 20 to 40 metres tall...
appears to improve the quality of habitat for the Greater Glider in forests dominated by E. obliqua. Another factor determining population density is elevation. Optimal levels are 845 m above sea level. Within a forest of suitable habitat, they prefer overstorey basal areas in old-growth tree stands.
Behaviour
Foraging
- Definitions and significance of foraging behavior :Foraging is the act of searching for and exploiting food resources. It affects an animal's fitness because it plays an important role in an animal's ability to survive and reproduce...
in the highest parts of the forest canopy. During the day, it spends most of its time denning in hollowed trees, with each animal using up to twenty different dens within its home range. The dens are often lined with leaves and strips of bark. This is why spotlighting
Spotlighting
Spotlighting or Lamping is a method of hunting nocturnal animals using off-road vehicles and high-powered lights, spotlights, lamps or flashlights, that makes special use of the eyeshine revealed by many animal species. A further important aspect is that many animals Spotlighting or Lamping (also...
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.
Within forests, males and females will have home territories and set borders between other members. For males, home territory ranges from 1.4 to 4.1 ha (3.5 to 10.1 acre) while that of females is only 1.3 to 3 ha (3.2 to 7.4 acre). 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.
The gliding posture of the Greater Glider 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. The animal regularly glides between high trees, and is able to use the tail to assist in steering. They avoid travelling along the ground whenever possible, and are slow and clumsy if forced to do so.
Greater Gliders do not make any loud sounds, and probably communicate through scent marking. The animal's cloaca
Cloaca
In zoological anatomy, a cloaca is the posterior opening that serves as the only such opening for the intestinal, reproductive, and urinary tracts of certain animal species...
l glands give it a generally musty smell.
Ecology
Greater Gliders subsist almost entirely on the young leaves and flower budBud
In botany, a bud is an undeveloped or embryonic shoot and normally occurs in the axil of a leaf or at the tip of the stem. Once formed, a bud may remain for some time in a dormant condition, or it may form a shoot immediately. Buds may be specialized to develop flowers or short shoots, or may have...
s of select eucalypt species, especially Eucalyptus radiata
Eucalyptus radiata
Eucalyptus radiata is a medium to tall tree to 30 m high with persistent bark on the trunk and larger branches or persistent to smaller branches. The bark shortly fibrous , grey to grey-brown, shedding in long ribbons...
, Eucalyptus viminalis, and Eucalyptus acmenoides
Eucalyptus acmenoides
Eucalyptus acmenoides, the White Mahogany is a common eucalyptus tree of eastern Australia. In the northern part of Sydney, where this tree grows on clay soils, the indigenous name is Barayly....
. Young leaves are preferred because they have higher concentration of nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
and lower concentration of lignocellulose (acid-detergent fibre). Overall, the eucalypt leaves are a poor source of nutrients.
Because of its night time activities, a natural predator on the glider is the Powerful Owl
Powerful Owl
The Powerful Owl , also known as the Powerful Boobok, is a species of owl native to south-eastern and eastern Australia, the largest owl on that continent...
(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. Other predators include feral cats, which are not native to Australia, being introduced with the arrival of Europeans.
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 pouchPouch (marsupial)
The pouch is a distinguishing feature of female marsupials ; the name marsupial is derived from the Latin marsupium, meaning "pouch". Marsupials give birth to a live but relatively undeveloped fetus called a joey. When the joey is born it crawls from inside the mother to the pouch...
, opening towards the forward part of the animal, and containing two teats. Only a single young is born each year.
At birth, the young weighs only around 0.27 gram (0.00952396976838023 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.
Greater gliders have been recorded as living for up to fifteen years.
Evolution
Although previously thought to be related to the other gliding possumsPetauridae
The family Petauridae includes 11 medium-sized possum species: four striped possums, the six species wrist-winged gliders in genus Petaurus, and Leadbeater's Possum which has only vestigal gliding membranes...
, the Greater Glider is now known to be most closely related to the ringtail possum
Pseudocheiridae
Pseudocheiridae is a family of arboreal marsupials containing 17 extant species of ringtailed possums and close relatives. They are found in forested areas and shrublands throughout Australia and New Guinea.-Characteristics:...
s, and especially to the Lemur-like Ringtail Possum
Lemur-like Ringtail Possum
The Lemur-like Ringtail Possum , also known as the Lemuroid Ringtail Possum or the Brushy-Tailed Ringtail, is one of the most singular members of the ringtail possum group...
, 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. Fossils of Greater Gliders are known from the late Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
onwards, and show that the animal was once more widespread, also being found in at least some areas of South Australia
South Australia
South Australia is a state of Australia in the southern central part of the country. It covers some of the most arid parts of the continent; with a total land area of , it is the fourth largest of Australia's six states and two territories.South Australia shares borders with all of the mainland...
.
External links
- WPSQ Wildlife page on Greater Glider (includes photo)
- Gliders in the Spotlight — Wildlife Preservation Society of QueenslandWildlife Preservation Society of QueenslandThe Wildlife Preservation Society of Queensland is a Queensland based conservation organisation. The Society was founded in 1962 by Judith Wright, Brian Clouston, David Fleay and Kathleen McArthur...