Greater glider

Although the genus was formerly thought to be monotypic, there are now known to be three species in the genus: • Central greater glider (Petauroides armillatus) • Northern greater glider (Petauroides minor) • Southern greater glider (Petauroides volans) The species are known to hybridize with one another near the edges of their ranges. ==Anatomy and physiology==

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. Greater gliders have a head and body 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 . 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 membranes stretching between the elbow and the ankle that give these animals 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. The first toe on the hind foot and the first two toes on the fore foot are opposable. These gliders 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. These animals can digest about 50–60% of the leaf during its passage through the gut. Their guts have a specialized caecum that contains a population 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 of dry matter daily. 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. ==Distribution and habitat==

Greater gliders are found in southern Queensland, eastern Australia, southeastern New South Wales, and the montane forests of the Victorian central highlands. It is usually tracked via spotlighting on transects (considered to underestimate the actual population size), radio tagging and owl-call playback. The greater gliders choose habitat based on several factors, with 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. Within a forest of suitable habitat, they prefer overstorey basal areas in old-growth tree stands. ==Behaviour==

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. 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 individuals. For males, home territory ranges from while that of females is only . 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 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. and are thought to communicate through scent marking. The animal's cloacal glands give it a generally musty smell. ==Ecology==

Greater gliders subsist almost entirely on the young leaves and flower buds of select eucalypt species, especially Eucalyptus radiata, Eucalyptus viminalis, and Eucalyptus acmenoides. Young leaves are preferred because they have higher concentration of protein, and lower concentration of lignocellulose which provides no nutrition. Overall, eucalypt leaves are a poor source of nutrients. 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. Other predators include feral cats, introduced to Australia 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 pouch, opening towards the forward part of the animal, and containing two teats. (P. minor) at Ravenshoe, Queensland == Evolution ==

Although previously thought to be related to the other gliding possums, the greater glider genus, Petauroides, is now known to be most closely related to the ringtail possums, 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 and inhabited other areas including parts of South Australia. == 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. Given the split into three species, and the uniquely threatened status of the southern species, this may need revision. ==References==