Thursday, July 9, 2009

Possums and Gliders

The Wet Tropics region supports the highest possum diversity in Australia. This exceptional diversity is even more extraordinary in that there are five possums which are endemic (found nowhere else). All of them except one - the Mahogany Glider - are rainforest specialists. They are the Herbert River Ringtail (Pseudocheirus herbertensis), the Lemuroid Ringtail (Hemibelideus lemuroides) brown and rare white colour morph, the Green Ringtail (Pseudochirops archeri) and the Daintree Ringtail (Pseudocheirus cinereus).

The rainforest species are restricted to the uplands and, as a consequence, they occur as a number of isolated populations. One example is the Lemuroid Possum which occurs only above 550 metres on the Atherton Tablelands but which has a smaller population on the Carbine Tablelands. The Carbine population of the Lemuroid occurs only above 1,000 metres and is characterised by many more "white" furred individuals.

Other possums and gliders can also be found in the Wet Tropics:

* the black and white Striped Possum;
* the tiny Long-tailed Pygmy Possum also found in New Guinea;
* the Squirrel, Greater, Feathertail and Sugar Gliders;
* the Yellow-bellied Glider, also sometimes called the Fluffy Glider;
* the Coppery Brushtail (a colour form of the very common Brushtail Possum which ranges down the east coast of Australia);and
* the Common Ringtail.

Mahogany GliderThe critically endangered Mahogany Glider (Petaurus gracilis) was thought to have been extinct since the 1800's but a living specimen was found in 1989. This glider is not rainforest dependent and prefers low woodland on swampy coastal plains, beach ridges and Melaleuca swamps. It eats nectar, tree sap, tree gum, lichens and invertebrates. This glider has been the subject of a government program to buy back critical habitat for the species as land clearing is the greatest threat to the glider's survival and most of its range falls outside the protective status of World Heritage.

Green Ringtail - Photo by Mike TrenerryThe Green Ringtail is so named for the strange illusion of colour provided by the black, yellow and white banding on each hair of its thick fur. It is easy to recognize during spotlighting as it has white patches below its ears and eyes. This possum's diet consists almost entirely of low protein, high fibre leaves, especially those of fig trees, and will also take ripe figs. The Green is the most solitary of the possums and does not have a den. It sleeps on branches by curling itself forward so that it resembles a large furry ball. This lack of a den may also explain why its single young clings to its mother's back longer than any other possum. Predators of this quiet and sedate possum include the Rufous Owl, the Spotted-tailed Quoll and the Amethystine Python.

The emblem of the Queensland Parks and Wildlife Service is an attractive black and white ringtail possum from upland and highland altitudes. The Herbert River Ringtail is also known affectionately as 'Herbie'. This ringtail likes leaves with a very high protein content, unlike the Green Ringtail. Their den is usually in a tree hollow or in large epiphytic ferns. Two young are produced and after nearly four months, they are ready to leave the pouch. The brown juveniles only require another two weeks being carried on their mother's back before they are ready to strike out on their own.

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