Diprotodont marsupials have successfully exploited virtually every terrestrial habitat their Australasian range has to offer. Forest diprotodonts include the cuscuses and tree kangaroos of tropical Queensland and New Guinea and Lead-beater's possum, which favors old growth highland forests of Australian mountain ash. Koalas and various wallabies and the widespread spectacled hare wallaby are animals of open woodland and bush, while rock wallabies are generally restricted to boulder slopes that less sure-footed animals find difficult to negotiate. Gray kangaroos and pademelons are grassland animals, preferring areas with regular rainfall and some tree cover, while reds make do with the sparsest vegetation in the Central Australian Desert. Honey possums (Tarsipes rostratus), quokkas (Setonix brachyurus), and various rat kangaroos are heath dwellers, while mountain pygmy possum is restricted to alpine habitats where snow covers the ground for half the year. Several species are now almost exclusively island dwellers, though not out of preference. Small wallabies such as the quokka and the rufus hare wallaby have been eradicated from much of the former range on mainland Australia by introduced predators and are only secure on offshore islands not yet colonized by foxes or cats. There are no aquatic diprotodonts, but several species of peturid, pseudochirid, and acrobatid possum readily take to the air on gliding membranes like those of flying squirrels. Not surprisingly, such species are restricted to habitats with many tall trees, from which they can launch their spectacular aerial swoops. Among the most adaptable of all marsupials, the common brushtailed possum, has adapted very well to the changes wrought by humans. It does well in suburban habitats and is a frequent visitor to gardens and outbuildings.

By no means all diprotodonts have regular nests, dens or other homes. The majority of large macropods are semi-nomadic and use a large home range. The red kangaroo (Macropus rufus) is especially wide ranging, and severe droughts or bush fires may force them to disperse 200 mi (300 km) or more in search of water and food. Being large, they have little need of a secure resting place, and most make do with patches of scant shade beneath desert shrubs such as saltbush. Smaller kangaroos and wallabies favor thickets of denser vegetation. While none of the large macropods build a nest as such, individuals may stake a claim to a particular spot. For example, the quokkas of Rottnest Island in Western Australia compete fiercely for the very limited number of shady resting places. The lack of potable water on the island in summer means that shade in which to avoid overheating is at a premium, and dominant individuals will claim the best spots as their own.

Unlike their larger cousins, many rat-kangaroos and bet-tongs do build a nest or den. Nest builders collect bedding material such as grass and vines, sometimes carrying them clamped between the body and the tail. These are arranged in a thicket of dense vegetation or in a shallow scrape, often

The common wombat (Vombatus ursinus) is an herbivore. (Photo by Animals Animals ©Robert H. Armstrong. Reproduced by permission.)

excavated in the shelter of a shrub or grass tussock. The West Australian boodie, a species of bettong, digs its own burrow or uses the abandoned tunnels of rabbits. Wombats are supreme diggers—their homes are extensive burrows in forests, grasslands or scrub.

Among the arboreal diprotodonts, most use some kind of customized resting place. Cuscuses prepare special sleeping platforms of bent twigs and leaves, while honey possums and pygmy gliders weave intricate nests of grass, shredded bark and moss. Most possums and gliders build nests of twigs and leaves and many will make use of ready-made possum or bird nests, hollow logs or naturally occurring tree holes. Both males and females build nests and the majority of possums will have several nests within a home range. Possum nests are sometimes referred to as "dreys."

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