The greater bilby is the size of a rabbit, and has a long-pointed nose, silky pale blue-grey fur with a tan belly, big ears and a crested black and white tail. They measure up to 55 cm in body length, and their tail can be up to 29 cm long. Males weigh 1-2.5 kg, while females are lighter and weigh 800 g-1.1 kg.
Their large ears are not for decoration, as they provide sharp hearing. This feature, combined with a strong sense of smell, is important for the greater bilby when looking for food. But all its senses aren’t that effective because the greater bilby can’t see very well. Interestingly when they run, they keep their nose down and this contributes to their unusual gait.
Habitat and Range
The greater bilby once ranged over most of mainland Australia. But the arrival of exotic predators has eliminated greater bilbies from most of their former range. Its closest relative, the lesser bilby, is extinct.
For many years there were no records of greater bilbies in Queensland, and some thought that the species had gone extinct in the state. The then Queensland National Parks and Wildlife Service (QNPWS) surveys in Diamantina Shire between 1981 and 1985 failed to find any greater bilbies, although they did highlight suspected greater bilby habitats. It wasn’t until QNPWS focused more lengthy surveys on these suspected areas and historic sites that greater bilbies were rediscovered in 1988.
Now the greater bilby is found in a few places in western Queensland. Queensland’s largest remaining group of greater bilbies lives in one area west of the Diamantina River in the State’s far west, which includes populations in Astrebla Downs National Park and Diamantina National Park. Greater bilbies have also been re-introduced into Currawinya National Park. Across the rest of Australia, the greater bilby is restricted to parts of the Great Sandy, Gibson and Tanami deserts in central Australia and the Pilbara and west Kimberley in Western Australia. Greater bilbies have also been introduced to various sites in Western Australia and South Australia and to Scotia Reserve in New South Wales.
Greater bilbies can live in a range of habitats that include Mitchell grass plains, sandstone ridges, gibber plains, rocky soils with little ground cover, hummock and tussock grasslands, and Acacia shrublands.
Greater bilbies are omnivores, which mean they feed on a range of foods including seeds, fungi, bulbs, and insects such as grasshoppers, beetles, spiders and termites. When looking for food, the greater bilby digs small holes up to 25 cm deep. These holes are scattered over greater bilby feeding areas.
The greater bilby has several distinctive features that it uses to find and gather its food. It uses its big ears and sharp sense of smell to find food, and it has a long, skinny tongue that it uses to lick up seeds from the ground. However, this feeding style means the greater bilby eats a lot of sand. In fact, 20-90 per cent of its faecal waste can be sand! Another feature is that it often eats the exoskeletons of insects, which shine in the light when their scat is broken open.
The greater bilby gets most of its water from its food rather than from drinking, which means it can survive in habitats without access to free standing water.
Greater bilbies live alone or in pairs. In the wild, greater bilbies live to about seven years old.
The greater bilby is a prodigious breeder. They begin to breed when they are six months old and can produce up to eight young a year. Female greater bilbies usually give birth to two young and as they can breed throughout the year, they can give birth up to four times per year. Female greater bilbies have an amazing short gestation period of just 12-14 days.
Like another endangered burrowing marsupial, the northern hairy-nosed wombat, female greater bilbies have a backward-opening pouch, which prevents soil entering the pouch when they are digging.
Young stay in the pouch for approximately 80 days and then, once they are out of the pouch, they stay in their mother’s burrow for a couple of weeks. During this time their mother is very busy moving in and out of the burrow so that she can forage outside for food and return regularly to feed her young.
As greater bilbies can live in a variety of habitats, eat a range of foods, survive without standing water, and breed rapidly, they should be more common then they are. So why isn’t the outback filled with greater bilbies?
In Queensland, the impact of predators such as foxes and cats has had the greatest effect on greater bilby numbers and continues to be the most serious problem.
The addition of artificial water points into the arid zone has contributed to the decline of greater bilby populations. This has come about primarily as a result of exotic predators being able to roam over greater areas when provided with access to additional permanent water. Greater bilby habitat fragmentation is also increasing as a result of indirect competition for food with rabbits and other factors such as changed fire patterns.
Did you know?
Text © Queensland Goverment (Dept of Environment and Heritage Protection)
Image © Jona Photography