The Greater Bilbies are the largest of the bandicoots, with bodies measuring up to 55cm in length and tails up to 29cm in length. Adult male bilbies weigh up to 2.5kg; females will weigh less than half this weight. Bilbies have very soft fur, typically blue-grey in colour, with white feet and belly area. Their tails are typically black in colouring with a white crest.
Habitat
The Wildlife Preservation Society of Australia’s fact sheet "The Bilby: Some facts about the Bilby from the Wildlife Preservation Society of Australia" explains that Bilbies were once widespread throughout Australia; however, their numbers have drastically declined over the last 100 years since European settlement. They now reside in some arid and semi-arid regions of Western Australia, Northern Territory and Queensland, typically where spinifex and dry grasses are found.
Bilbies live in underground burrows of up to three metres in length, and two metres deep.
Diet
Bilbies are omnivores, meaning they will eat a variety of plants and animals, including:
- seeds;
- spiders;
- insects and their larvae;
- bulbs;
- fruit;
- fungi;
- small animals.
They do not drink water, as they receive all of their fluid requirements via their diet.
Dentition
Bilbies mouths contain 48 teeth: 26 upper and 22 lower teeth on each side of their jaw.
The upper set of teeth conist of:
- five incisors;
- one canine;
- three premolars;
- four molars.
The lower set consists of:
- three incisors;
- one canine;
- three premolars;
- four molars.
Behaviour
Bilbies are nocturnal marsupials. They will not emerge from their burrows until at least one hour after dusk, and will re-enter it at least one hour prior to dawn. They will not leave their burrows in the event of a full moon, strong winds or heavy rains.
Hearing
Bilbies' ears very large and almost hairless, providing them with exceptional hearing. Their ears are also thought to aid in temperature regulation. They possess the ability to move and rotate their ears at different angles; including flat against their body and folding them in half.
Smell
Bilbies' snouts are long and hairless at the tips, and provide them with an excellent sense of smell.
Vision
Bilbies possess very poor vision. Their black eyes are up to 1cm diameter and surrounded by black eyelashes.
Breeding
Bilbies are marsupials with a backwards-opening pouch, which helps to prevent dirt from entering during digging. They breed all year round, and have a gestation period of 12 to 14 days (the shortest of all marsupials). Females give birth to one to three young, which remain in her pouch from 75 - 80 days; they will become independent of their mother approximately two weeks after leaving her pouch.
Reasons for the Decline of Bilbies
There are a number of reasons for the decline of bilbies, including:
- loss of habitat as a result of agriculture (tree clearing, farming crop and domestic livestock);
- competition for food from introduced species, including cattle, sheep and rabbits (which also compete for their burrows);
- predation from introduced species, particularly foxes and feral cats. Dingoes, snakes, goannas and birds of prey will also hunt and kill bilbies;
- hunting bilbies for their skin was common in the late 18th century, thereby drastically reducing their numbers. In addition, many bilbies were killed by traps or poisons intended for rabbits.
Sources:
The Australian Bilby Appreciation Society. “What is a Bilby Anyway?” 2002 http://www.members.optusnet.com.au/bilbies/About_Bilbies.htm
Wildlife Preservation Society of Australia. “The Bilby: Some facts about the Bilby from the Wildlife Preservation Society of Australia”
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