Name(s): Greater bilby (Macrotis lagotis); other names in Indigenous languages include walpajirri, ninu, mankarr, pingki-tawutawu, marrura, warrikirti, tjalku, nyarlku, yinpu, mirtuluju, muntalgnaku, nyarlgoo, birndirdiri, kulkawalu, nirlyari, jirrartu, jawinji
Size: Body length: 29-55cm, tail length 20-29 m, weight 0.6-2.5kg.
Diet: Generalist omnivore – insects and their larvae, seeds and fungi, bulbs and fruit.
Habitat: Once widespread across Australia, populations are now restricted to parts of the Tanami, Great Sandy and Gibson Deserts and the Kimberley and Pilbara regions, with small populations in south-west Queensland and north of Alice Springs.
Conservation status: Vulnerable
Superpower: Greater bilbies are diligent and hard-working excavators, capable of digging multiple large burrows (up to 2m deep) within hours. These burrows make for important refuges, not only for bilbies, but for many other animals known to use them!
The greater bilby is the largest of the bandicoots, and easily the most charismatic and iconic – which other animal gives the Easter bunny a run for its money? But they differ by having a longer, striking tail, disproportionately bigger ears, and softer, silkier fur. They were aptly described by Australian mammologist Hedley Finlayson (1935) as having “a number of structural peculiarities to grotesque lengths yet manages to reconcile them in a surprisingly harmonious, and even beautiful, whole.”
Greater bilbies are excellent burrowers, digging extensive tunnel systems with their strong forelimbs and well-developed claws. This work keeps them busy! They regularly dig new burrows and can occupy up to 18 burrows at any one time. Coupled with their foraging habits, this makes the greater bilby an important “ecosystem engineer”. By turning over soil, bilbies create depressions that catch organic matter, increasing the amount of beneficial nutrients in the soil. Their burrows also make good homes for other desert-dwelling animals, including other small mammals, reptiles and birds.
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The greater bilby is also a culturally important species, highlighted by the many different Indigenous names used across Australia. The name “bilby” is derived from the Ullaroi language name “bilba”, although there are at least another 20 names used across the country. The greater bilby is often featured in cultural stories, song lines, beliefs and laws, and Indigenous people have an intricate understanding of its ecology. Most of the bilby population now occurs on Indigenous land, and in many local areas, bilby persistence is linked to ongoing management being undertaken by Traditional Owners and Indigenous rangers.
Greater bilbies shelter in their burrows during the day, emerging after dark to forage for food. They are the only (living) desert-dwelling animal known to expose and rip open plant roots in search of larvae (a well-known example being witchetty grubs), creating unique diggings at the base of shrubs and forbs. They also feast on other insects (including beetles and termites), as well as plant material like seeds and bulbs, which can sometimes be difficult to find. Consequently, greater bilbies are highly mobile – an individual can move up to 2-3km per night! They are known to colonise new habitats, particularly in less productive parts of their range. These behaviours allow them to adapt to their conditions and take advantage of patchy food resources.
The greater bilby is certainly a fighter – it is the last surviving desert-dwelling bandicoot, having held on longer than its counterparts, and is the only remaining member of its family, following the extinction of the lesser bilby (Macrotis leucurua) in the 1960s. But while it’s outlook may be better than some of our other tragically extinct critters, it’s not without consequence – the greater bilby has declined significantly, to about 20% of its original range. This decline has been more severe in the eastern and southern parts of its distribution and can be attributed to the usual suspects – a combination of changing fire regimes, predation by foxes and feral cats, over-grazing by livestock, and competition from other feral herbivores, particularly rabbits.
Reintroduction efforts have been successful, particularly in areas excluding foxes and cats – the greater bilby currently persists as several translocated populations, including on predator-free islands, in mainland fenced enclosures, and in areas where foxes and cats are heavily managed. But protecting the greater bilby in the wild is challenging, primarily due to difficulties associated with managing bilbies and their threats at large spatial scales. Good fire management and targeted feral animal control are likely our best bets.
The epitome of cute and furry (not-to-mention tough – we’re talking about the sole survivor of the desert bandicoots here), a long-time Australian icon, and a species of great ecological and cultural significance, I’m sure you can agree that the greater bilby deserves your vote for Australian Mammal of the Year!