Brush-tailed bettong, Brush-tailed rat kangaroo
Woylie, or otherwise known as Brush-tailed bettong, has a long, flexible and brush-like tail, which acts like a 'fifth limb', helping the animal transfer materials to the nesting site. This tiny kangaroo is the size of a guinea pig. The dense fur of the animal is grey-brown on the upper part and pale white-brown on the under part. When moving around, Woylie usually hops on its powerful hind legs, holding the shorter fore-legs close to the belly. Woylies typically live 4 - 6 years. However, these animals are known to live up to 9 years in the wild and as long as 14 years in captivity.
Woylie is native and endemic only to Australia, where this animal occurs in different habitats, including temperate forests and desert grassland. However, preferred environment of Woylie is in open forest or woodland with a low clumped understorey of tussock grasses or woody shrubland. Original populations of Woylies presently inhabit Perup Nature Reserve, Tutanning Nature Reserve and Dryandra Woodland in south-west Australia. In addition, there as introduced populations of this species in Western Australia, South Australia and New South Wales.
These solitary animals associate with conspecifics only during courtship as well as when mating and raising offspring. Both males and females of this species have their own territories. Each home range has a nesting and a feeding area. While nesting is territorial, their feeding areas can often overlap. During the day, Woylies spend their time in their nests, coming out to find food only by night. Woylies are known to be very aggressive species. Like kangaroos, they usually defend their rights when encountering each other in a feeding area. During confrontations, Woylies challenge opponents by lying on their side and accompany kicking at one another with guttural arguing.
Little is known about the mating system of Woylies, but as these animals socialize only for mating and rearing young, it may mean they have a polygynous mating system. Breeding occurs year-round, while gestation period lasts for 21 days. Females yield up to 3 young per year with a single baby (rarely twins) at a time. Newborn babies of these marsupials are undeveloped. Immediately after birth, young are moved to the pouch of their mother, where they find protection, feeding upon maternal milk and continuing to grow for the following 3 months. Leaving the pouch of its mother, a joey will travel with its mother at heel until the next joey comes out of the pouch. Females of this species are ready to produce offspring at 6 months old, giving birth at intervals of 3.5 months.
Woylies were originally considered to be pest animals. Hence, in 1880-1920, they were directly killed in huge numbers (more than 3 million individuals) for reward. Woylies have also suffered from predation by introduced animals, particularly, foxes and cats. On the other hand, competition with introduced animals such as rabbits and feral pigs is another threat to the population of this Critically Endangered species. In addition, they are exposed to disease transmission from feral pigs. They also face reduction of their range as a result of changing fire regimes and agricultural development. Woylies are threatened from degradation of their natural habitat due to land clearing as well as reduction of their terrestrial habitat because of anthropogenic emissions of greenhouse gases.
According to the IUCN Red List, the total population size of the Woylie is around 12,000-18,000 mature individuals. Specific populations of this species have been estimated in following areas: Wedge Island - 1,500 individuals; St. Peter Island - 2,000 individuals; Venus Bay Peninsula - 1,500 individuals; Peron - 100 individuals; Tutanning Nature Reserve - 100 individuals; Julimar - 200 individuals; Boyagin - 100 individuals. There are now fewer than 50 Woylies in Lincoln National Park and fewer than 50 individuals - in Venus Bay Island. Currently, Woylies are classified as Critically Endangered (CR), and their numbers are decreasing.
Woylies play a key role in the ecosystem of their habitat. These animals are, in fact, ‘engineers’ of local ecosystem. On one hand, they serve as important seed dispersers due to carrying seeds of certain plants in their cheeks (in order to later eat or bury) and thus helping these plants survive. On the other hand, Woylies benefit the ecosystem by digging (they look for fungi and tubers), hence increasing water penetration into soil, trapping seeds and organic matter as well as dispersing fungi, which is highly beneficial for plants.