- Kingdom: Animalia
- Phylum: Chordata
- Class: Mammalia
- Order: Diprotodontia
- Family: Potoroidae
- Genus: Bettongia
- Species: Penicillata
- Another name: Brush-tailed Bettong, Rat Kangaroo
- Average Length: 11.8-15 in (30-38 cm)
- Average Tail Length: 11.4-14.2 in (29-36 cm)
- Average Weight: 3 lbs (1.4 kg)
The woylie is a small macropod species, a plant-eating marsupial mammal of an Australasian family that also comprises kangaroos and wallabies. It has greyish-brown fur on the upperparts and flanks with pale grey fur on the underside.
It is found in a variety of habitats, from temperate forests to desert grassland. But, it is most commonly lives in open forests and woodlands where there are low clumped understory of tussock grasses or woody shrubland.
Like most marsupials, the woylie is native to Australia, from Southwestern Australia to central New South Wales. Today, it only occupies a small fraction of its historical range; in the past, it inhabited over 60% of Australia. Original populations of this tiny creature exist at Perup Nature Reserve, Tutanning Nature Reserve, and Dryandra Woodland in southwest Australia. Introductions have already begun in other sites within Western Australia, South Australia, and New South Wales.
Similar in appearance to a small kangaroo, the woylie typically stands and hops on muscular hind limbs while holding its shorter forearms close to its belly. And just like the kangaroo and other marsupials, females have a well-developed pouch for their babies. The tip of the muzzle is naked and flesh-colored. Its fur is extremely dense, has relatively large eyes, and has small, round eyes. On its feet, the creature has pale-brown spiky hairs and long claws. They also have cheek pouches to store food .
The woylie has a long, partially prehensile tail that has a black, brush-like crest along the top part towards the end; hence, the origin of one of its names: brush-tailed bettong. The tail enables the animal to use it to carry nesting materials.
Unlike many types of animals, the male and female look similar.
Woylies are primarily fungivorous. Their food consists largely of the fruiting bodies of underground fungi, supplemented by bulbs, tubers, seeds, insects, and resin. However, there have been a few reports of their feeding on carrion, meat, and marine refuse.
It is able to locate its food by using its keen sense of smell to detect and dig up with its robust front claws. It has a special stomach containing abundant bacteria. The natural flora enables for the breakdown of the fungi and the release of digestible nutrients.
Fungal spores are not digested and are usually deposited in feces in a new location, thus creating a mutually beneficial relationship. The fungi also benefit trees, as they assist with nutrient uptake from the soil. Therefore, keeping Australia’s forests healthy.
The woylie is a nocturnal creature, retreating to their nests during the day. Their nests are simple, constructed from long grasses, bark, or sticks and are usually located at the base of an overhanging bush and other thickets of vegetation.
It is also a solitary animal; the only time they are found together is during courtship and mating. There is no breeding season as they breed all year round. Typically females mature at the age of 170-180 days. Gestation period is around 21 days. While females giving birth to one or two young (up to three depending on environmental conditions), called joeys, only one will ever be raised. The joey will remain in their mother’s pouch from 90 to 110 days before leaving the pouch as an adult.
The woylie is currently listed as ‘critically endangered’ because of a drastic, ongoing population decline it has experienced. It is estimated that their population has declined by more than 80% within a ten year period. Since 2001 with 15,000 individuals, the population is approaching a total of 6,000 in the wild with 161 in zoos in 2005.
For the most part, the cause of this dramatic population decline is a mystery. Although some small populations have declined or disappeared, large declines have also occurred in all large populations, most likely due to density dependence. There is some hope that in a couple of years, declines will begin to stabilize, allowing the species to persist at lower densities. However, within a year or two, the decline rate will have caused there to be only about a 1,000 individuals left in three original populations.
At the time of European colonization, the woylie inhabited much of Southern Australia, southern Queensland, and from Western Australia to the western plains of the Great Dividing Range in New South Wales.
Since then, habitat loss and alteration as well as fox (historically) and cat predation have been the major causes behind the loss. Extensive areas occupied by the woylie were cleared for agriculture and they were considered as agricultural pests or for the fur trade in the late 19th century through the early 20th century. Relict populations survived where shrubs of Gastrolobium contained fluoroacetate (1080 poison) provided suitable shelter, presumably reducing the impact of foxes and also reducing competition from rabbits and stock.
Disease, from low genetic diversity, could also be possibly responsible for historical declines.
Conservation efforts to re-establish populations in the 1980s and ‘90s were concentrated on controlling the feral fox while reintroducing woylies to fox-free sites in its former range. Some translocations have failed, but others succeeded in establishing populations in other southwest forest areas of Western Australia as well as in Venus Bay, St. Peter Island, Wedge Island in South Australia, Shark Bay World Heritage Area in the Peron Peninsula, and Scotia Sanctuary in NSW. For more recent ones, it is too early to know whether or not they have succeeded. Future projects are also beginning to be planed; they will be among the species reintroduced to Dirk Hartog Island as part of the ecological restoration project for the island.
However, these translocated populations are usually small and started with few individuals. For example the population on Wedge Island of 1,500 individuals was founded from only four individuals. This makes them susceptible to issues of genetic viability as well as to stochastic events.
- Woylies use their prehensile tail to collect grass blades and branches to build their nests
- There are two subspecies of the woylie (Bettongia penicillata penicillata and Bettongia penicillata ogilbyi), although B. p. Penicillata is considered extinct. However, the historical geographical relationship between the two is uncertain and their common names are used interchangeably.
- Their common name comes from the Nyungar language ‘walyu’, meaning kangaroo rat
- In the wild, woylies do not drink water or eat any green plant material
- Just after the first young is born, the female can mate again. But, because of embryonic diapause, development is delayed and parturition of the second young will not take place for four months. This ensures that the first young will mature before the second is born.
- Its downward population trend will also affect surrounding habitat because of the dependence of fungi on the woylie for dispersal
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