Brush-tailed bettong: the ultimate truffle connoisseurs

Name(s): Brush-tailed bettong (Bettongia penicillata ogilbyi) or woylie

Size: Length 40cm from head to base of tail, weight 1.2kg

Diet: Fungivore, meaning that they eat the fruiting bodies of fungi (including truffles!). They also eat tubers, seeds, insects, and resin.

Habitat/range: South-west Western Australia and in fenced reserves around the country, but was once found across most of continental Australia.

Conservation status: Endangered

Superpower: Has the most explosive vertical leap of any creature alive!

Have you ever wondered what a T-Rex might look like if it was small and had fur? Well, wonder no more. Let me introduce you to the woylie!

Woylie is the Nyoongar name for the brush-tailed bettong. In South Australia, where they have been reintroduced to the Yorke Peninsula, the Narrungga people call them Yalgis.

Once an important food source for indigenous peoples, woylies were well known by European newcomers as a pest of crops and vegetables and for causing chaos among agricultural communities. Active at night, the woylie was frequently recorded as haunting stables and haystacks at night to get to the grain in the ears of the wheat.

A small rat-like marsupial stands on the ground, surrounded by yellow leaves
A brush-tailed bettong (Bettongia penicillata ogilbyi). Credit: Natasha Harrison

But the traits that made woylies a nuisance for early settlers are the same traits that make them an important part of their environment. Woylies are ecosystem engineers, meaning they play a critical role in keeping their habitat healthy and sustainable. A single woylie (remember they are around 1.2kg) turns over approximately 5 tonnes of soil per year – that’s more than the weight of three hatchback cars! This digging activity aerates the soil, helping leaf litter to break down and encouraging seeds to germinate.

Woylies also help to disperse seeds by collecting and caching them underground, and by pooing them out around their territory. This is an essential part of the life cycle of many plants, including the threatened sandalwood tree.

Woylie diggings in the ground
Woylie diggings are important for aerating and turning over the soil. Credit: Chloe Frick

As marsupials, woylies birth a small, unfurred young into their pouch, where it develops over 100 days. They are very effective at producing young and can produce up to three in one year.

Woylies are also capable of “embryonic diapause” meaning they can delay the growth of a fertilised egg until the current young has left the pouch – so  they can then have one ‘bun in the oven’ while another is at heel. However, they aren’t always the most caring parents.  In situations where they perceive a predation threat, mothers may sacrificially eject their joey to provide a distraction while they escape.

Voting for Australian Mammal of the Year 2023 is now open!

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Using their prehensile tail as a fifth limb, woylies can carry bundles of nesting material such as grass, shredded bark, sticks and leaves that they use to build discreet dome shaped nests under vegetation.

Once found across most of south and central Australia, woylies are now only extant in two regions – the Upper Warren and surrounding Dryandra woodlands in the SW of Western Australia.

A woylie nest made from sticks and grasses in the image on the left. On the right an image of a woylie captured in a black bag, with its tail curled up
A woylie nest (left) made from sticks and grasses. Woylies have prehensile tails (right) that they use to carry nesting material. Credit: Natasha Harrison

Woylies have experienced a rollercoaster ride of threat statuses. After substantial declines, they were listed as “Rare or Likely to Become Extinct” in the 1970s, before targeted control of introduced predators in woylie habitat saw the population recover substantially. By the 1990s, the species had been delisted and hailed a conservation success, only for the population to experience broad scale crashes and be relisted in 2008 as “Critically Endangered”. This is thought to be primarily due to habitat loss/fragmentation and predation from introduced predators. In response to these large population declines, woylies are the most translocated species in Australia (with over 70 translocations), present in more than 15 predator-free fenced or island havens where they thrive.

Despite facing many adversities, the iconic woylie persists, continuing to keep our ecosystems healthy. It is for this reason that these charismatic macropods should be crowned Australian Mammal of the Year!

A woylie bouncing along the ground at night
Woylies are also capable of “embryonic diapause” meaning they can delay the growth of a fertilised egg until the current young has left the pouch. Credit: Natasha Harrison

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