Missing marsupials

When it comes to quirky animal names, the fat-tailed dunnart would have to be up there with the sarcastic fringehead and screaming hairy armadillo. They’re all real, and one of these used to be considered abundant in a location not far from the Wirribi Yaluk/Werribee River estuary. Recent studies, however, suggest a different story.

The grasslands of Victoria once covered 30% of the state, and were rich in wildflowers, grasses, shrubs and yes, trees. This ecosystem was home to numerous species of insects, birds, reptiles and marsupials, and was an important region of places and resources for Traditional Custodians. One of the smallest mammals found here is a tiny creature called the fat-tailed dunnart. Don’t be fooled by their sweet furry faces and huge dark eyes. These creatures are from the Dasyuridae family, which includes quolls and Tasmanian devils.

Dunnarts are one of the smallest carnivorous marsupials, weighing between 10-20 grams. They are found across the Australian continent, usually inhabiting grasslands and often surviving in areas that have been converted to farmland. In the Victorian grasslands, fat-tailed dunnarts nest in cracks in the ground (a common feature in basaltic clay soils), under logs and rocks. They are ferocious hunters, feeding on a variety of small prey including beetles, spiders, centipedes and occasionally small reptiles. During winter dunnarts enter a type of hibernation to conserve energy, nesting underground (this is where the fat stored in their tail comes into use). Occasionally, they curl up with introduced mice to share warmth for this period of dormancy. But come spring, the dunnarts wake up hungry – and then eat their nestfellows.

The Western Treatment Plant near Werribee has long been considered as a stronghold of fat-tailed dunnarts, due to surveys in the 1970’s that recorded hundreds there. In 2019, Emily Scicluna from La Trobe University set out to revisit these survey sites as part of her PhD research. Over the course of 12 months, all the sites where fat-tailed dunnarts had previously been found were investigated, with thousands of locations checked. Not a single fat-tailed dunnart was found.

Emily’s findings led her to the realisation that this “common” marsupial was actually a Threatened species. Under this classification by the International Union for Conservation of Nature (IUCN), a species can receive greater protection under law. By compiling a great deal of data and evidence, Emily was able to fulfil IUCN criteria to have fat-tailed dunnarts listed as ‘Vulnerable’ in Victoria. Does this mean they will be protected now? Perhaps.

The causes of this decline may include changes to the landscape including agricultural processes, exotic grasses outcompeting native tussocks, lack of fire in a landscape that was previously managed with Indigenous firestick techniques for tens of thousands of years, and levelling of sites which has removed rocks and flattened the ground. The introduced predators foxes, cats and rats have been implicated in numerous extinctions of species across Australia and can also prey upon dunnarts.

These diminutive creatures are a vital part of our grassland ecosystems. Along with bandicoots, bettongs and potoroos, which once roamed the Werribee plains, our native mammals have all but disappeared. Emily’s research highlights how we can take for granted the presence of a creature, thinking it secure, only to find it has quietly decreased at an alarming rate.

We may not be able to reverse the decline of grasslands in our own backyards but we can help native species by choosing indigenous plants, removing invasive weeds and exotics, and keeping cats indoors. Discover conservation programs that are working for the future of grassland species by visiting parks, watching documentaries and supporting organisations and community groups. Together, we can make a difference.

To read more about Fat-tailed dunnarts and Emily Scicluna’s research, go to:

I realised the fat-tailed dunnart was under threat. Here’s how I got the species officially listed (theconversation.com)

Fat-tailed dunnarts (Sminthopsis crassicaudata) of the Werribee grasslands: a case study of a species in decline (csiro.au)

Local places you can visit that support the conservation of grassland and threatened species:

Mt Rothwell | Conservation and Research Reserve | Little River

Werribee Open Range Zoo

Nature connection through stories:

Home – Remember The Wild

Featured dunnart images: Courtesy Emily Scicluna.

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