The Greater Bilby

Australian Endangered Species Profile Sheet
Common Names: Greater Bilby, Rabbit-eared Bandicoot, Bilby, Dalgyte, Ninu

Scientific Name: Macrotis lagotis

Conservation Status: Vulnerable



DESCRIPTION

Bilbies are the largest of the bandicoots with a body up to 55cm long and a tail as long as 29cm. Adult females weigh about one kilogram and males almost twice that. Bilbies have soft silky fur, which is ash-grey in colour except for on the belly where it is white or cream. The tail is grey near the body, black further down and white on the last half. The long tail hairs form a crest and the tail ends in a spur which has no known purpose.

The long hairless ears of Bilbies are probably important in keeping them cool as well as for hearing predators. Bilbies have long snouts and long slender tongues. Although they have poor vision, their senses of smell and hearing are very good. This is important for finding food and avoiding danger.

The strong front limbs have three toes with claws and two without claws which Bilbies use to burrow rapidly. The hind limbs are slender and rather like a kangaroo's with a very large middle toe. The hind limbs are used for grooming.

DISTRIBUTION

In the late 1800s and early 1900s Bilbies were extremely common. They lived in most of the southern half of Australia from the coast of Western Australia to mid-west New South Wales and south-west Queensland. In the 1950s the biologist Finlayson described Bilbies as "one of the most plentiful and universally distributed of central Australian mammals".

Bilbies are now only found in scattered parts of the Tanami Desert in the Northern Territory, in the Great Sandy Desert, Gibson Desert, Pilbara and Kimberley regions of Western Australia and an isolated population lives in south-west Queensland.

HABITAT

Bilbies used to live in many different habitats across Australia wherever the climate was fairly dry. Areas with better soils and rain were changed by farming and grazing, leaving only the very dry regions of inland Australia.

Bilbies are now mainly found in grasslands and acacia shrublands with spinifex and tussocks. They only live where there are few rabbits and foxes.

ECOLOGY

Bilbies build burrows that spiral downwards to a depth of about two metres. Each animal may use up to a dozen burrows, each with only one entrance that is usually hidden by a small bush, grass tussock or termite mound.

Bilbies are nocturnal (active at night) and shelter in their burrows from the heat of the day. At night, a Bilby may travel up to five km as it searches for food. Bilbies are omnivorous (feed on animals and plants) and will feed on whatever food is available each season. They eat insects and insect larvae as well as bulbs, fruit, fungi and seeds which they lick from the ground with their long tongues. Bilbies also use their front feet to dig for food.

Generally, Bilbies live alone but they may live in small groups of two to four animals, when the home ranges of an adult male, female and their young overlap. It is possible for young to be born throughout the year, but breeding may depend on rainfall and the amount of food around. Bilbies have from one to three young which stay in the pouch for about two and a half months. They stay with their mother for another two weeks before leaving the home burrow. No one knows how long they live in the wild, but captive Bilbies can live for about five years.

THREATS TO SURVIVAL

Early this century Bilbies were hunted for their skins, and many were caught in rabbit traps and killed by poison baits.

Bilbies are preyed on by foxes and feral cats. They have to compete for food with rabbits and livestock. Their supply of food has also been affected by changes in the number and strength of fires since European settlement in Australia.

Bilbies can move around to find food but in severe drought they depend on areas with a good supply of food. Other animals, including rabbits and cattle, also depend on these patches, which become overused, and may not be able to keep Bilbies and other native species alive during drought. After a long drought, colonies of Bilbies may have a smaller chance of increasing in numbers. In this way the Bilby population could decrease every time there is a long drought.

Bilbies now live in small scattered populations often a long way from other Bilby populations. These populations may not be able to survive a disaster such as disease, fire or severe predation.

RECOVERY ACTION

Some Bilbies are kept in captivity so that they can be studied. Bilbies breed well in captivity and could be put back into areas where they have died out. This could only occur if the causes of their disappearance are understood and controlled.

In Western Australia, Bilbies live on protected land in the Gibson Desert Nature Reserve, in the Great Sandy Desert at Rudall River National Park and the proposed Percival Lakes Nature Reserve.

In the Northern Territory studies over the next few years will look at the movement, growth, breeding, habitat use and survival of Bilbies in the wild. This should show if numbers are decreasing or remaining the same, what is stopping the population from increasing and spreading, and how much predation Bilby populations can survive. Since 1980 there have been some attempts to reintroduce Bilbies into Watarrka National Park (350km south of Alice Springs). These did not succeed partly because of cat predation.

In south-west Queensland Bilbies live in the new Diamantina Lakes National Park, but the biggest population is found on private land. In these areas burrows are being located to find out how many Bilbies there are and where they live, and their ecology is also being studied. A study of feral cats in the same area should show how they are affecting the survival of Bilbies.

RELATED SPECIES

Lesser Bilby (Macrotis leucura)

The Lesser Bilby was last reported alive in north-eastern South Australia in 1931 and is now presumed extinct. This bandicoot had white fur along the top of its tail and was smaller and less colourful than the Greater Bilby. The Lesser Bilby closed the entrance to its burrow when inside. It was noted to feed on small rodents and mice, as well as seeds. Females reared up to two young at a time.

DEFINITIONS

Presumed Extinct: An animal or plant species that has not been found in the wild during the past 50 years, despite thorough searching.

Endangered: An animal or plant species that is in danger of extinction and will probably not survive if the threats to it continue.

Vulnerable: An animal or plant species that will probably become endangered if the threats to it continue.

MORE INFORMATION

Flannery T (1990) Australia's Vanishing Mammals. R D Press, Sydney.

Stoddart, E (1992) Bandicoots and Bilbies of Australia. Bimberi Books, ACT.

Strahan R (1983) The Australian Museum Complete Book of Australian Mammals. Angus and Robertson.

Greater Bilby Recovery Plan. Available soon from the Australian Nature Conservation Agency for $10.

Illustrations copyright Sue Stranger, Kaye Kessing and Patrick Cook (most not in the electronic edition)


Endangered Species Unit
Australian Nature Conservation Agency
GPO Box 636
CANBERRA ACT 2601
Phone: 06 250 0200

February 1994


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