Greater Bilby

SPECIES Greater Bilby
TAXONOMY Macrotis lagotis
STATUS Vulnerable (Redlist.org); Vulnerable AUS (ala.org.au); Endangered/Extinct in some states

The Greater Bilby has been immortalised as Australia’s very own bearer of Easter goodies. It is believed to have inhabited the continent for up to 15 million years, and has featured in the stories of Aboriginal Australians. Where once abundant, they have been pushed more into arid landscapes since European settlement. 

Considered to be an ecosystem engineer, its ability to shift soil in the tunnelling of complex subterranean tunnels provides a vital service. The movement of soil and organic matter from deep underground to the surface improves the nutrient value, the spread of important mycorrhizal fungi (help plants absorb nutrients), and water penetration. The tunnels also provide shelter for other insects, birds, reptiles, and small mammals. With strong forelimbs and claws, the Greater Bilby has transformed habitats as it digs a new burrow every few weeks that can be two meters underground and three meters long. It shifts up to 1.5 tonnes of soil every year.

They are nocturnal creatures, only emerging to forage at night. Their long snout and tongue will seek out tubers, seeds, spiders, and termites. They rely on their hearing and sense of smell to safeguard against predators, and rarely stray too far from their burrow.  They are successful in arid regions because they obtain enough moisture from their food sources. They also ingest large quantities of dirt.

Appearance
The Greater Bilby is similar in size to that of a domestic cat. It has blue-grey fur and very long pinkish ears. The male is larger than the female, up to 55 cm long with the tail extending a further 30 cm. The male weighs up to 2.5 kgs. They will live up to 10 years in the wild.

Reproduction
Reproduction can occur year round if food supplies are available. As a marsupial, the female will give birth to up to three premature joeys who will attach themselves to a teat inside the mother’s pouch. As the bilby burrows constantly, the pouch is backward facing to protect the young. The joeys will remain in the pouch for around three months.

Threats
There were originally two species of Bilbies: the Greater Bilby and the Lesser Bilby (Macrotis leucura). Today, the Greater Bilby is simply referred to as the ‘Bilby’ because the Lesser Bilby subspecies is thought to be extinct as it has not been seen since the 1950s. Declines have been occurring more rapidly just over the last decade.

There are key threats to current populations. The bilbies are forced to compete for food with domestic livestock and introduced species such as the rabbit. Changing fire patterns affect native vegetation and regrowth patterns which promote food plants. Bilbies do rely on native grass seeds as part of the omnivore diet. The Bilby is also the victim of predation by introduced species such as foxes and feral cats.

Although areas have been fenced and are monitored, the Greater Bilby no longer enjoys the majority of its native habitat. If it is not closely guarded, the species will be at risk and will disappear from the wild.

Updated 5 May 2021