Bilby skull

Educational value

• The bilby, also called the greater bilby or rabbit-eared bandicoot, is the largest of the bandicoots and the only remaining species of bilby. Once widespread throughout Australia, this marsupial now occurs in fragmented populations in the arid desert regions of the Northern Territory and Western Australia, and in an isolated region in south-west Queensland. It is listed as vulnerable under Australia's 'Environment Protection and Biodiversity Conservation Act 1999'.
• The bilby has long silky, blue-grey fur with light brown patches around its hips. The underparts and feet are whitish, and it has a long crested black-and-white tail, 20-29 cm in length. Bilbies have long pointed ears, long snouts and compact bodies. The head-and-body length is 30-55 cm. Bilbies are nocturnal and omnivorous, feeding on insects, fungi, fruit, seeds and tubers. They shelter by day in deep burrows.
• The bilby has three pairs of distinctly small and sharp lower incisors, and five pairs of upper incisors. Bilby dentition is also characterised by its particularly large canines, larger in the males, which use them for displays of aggression. They have three pairs of compressed premolars and four pairs of molars in the upper and lower jaws, and there is a wide gap between the canines and the premolars.
• Marsupial skulls differ significantly from placental mammals in their dentition and jaw bones, and have a comparatively large face area and small brain case. Marsupials generally have more teeth than placentals with only some being replaced throughout their life, whereas placentals replace their first 'milk' teeth. Typically marsupials have three premolars and four molars on each side in both jaws, one pair of canines and two (diprotodont) or four (polyprotodont) lower incisors.
• The Australian marsupials are a diverse group containing around 160 different types in three main lineages, identifiable by differences in their skulls and dentition, developed as they adapted to various habitats and food types. One lineage consists of the mostly herbivorous diprotodonts, such as koalas, wombats and wallabies. A second lineage consists of the bandicoots. The third consists of the marsupial moles and dasyurids, including the Tasmanian devil, dunnarts and quolls.
• The mammal skull is a complex fusion of around 34 bones, in three main parts: the braincase, which encloses the brain, the rostrum including the snout and upper jaw, and the lower jaw or mandible. The mammal skull is distinguishable by the presence of three bones in the middle ear used for hearing (not visible in the image). It also has a unique jaw joint - the single lower jaw bone connects with a small skull bone (the squamosal), resulting in a distinctive jaw movement.
• There are three types of existing mammals, the placentals, the marsupials, and the primitive monotremes. Placental mammals give birth to live young after extended nourishment from a placenta in the mother's womb, marsupials are characterised by a pouch for rearing the young, and monotremes are egg layers. There are many shared characteristics between these three groups and some important distinctions, especially in the skull and dentition.

Year level

5; 6; 7; 8; 9; 10; 11; 12

Topics Alphabets (Writing systems) Bilbies Jaws