Aboriginal people do not traditionally view their 'art' in the way westerners do. Although they are coming to understand our strange attitudes towards art, it is foreign to their understanding, and probably just one more way in which we appear quite weird to them.
To the Australian Indigenous people, their art is both more practical and more spiritual. It is a visual expression of a story, one that is integrated with dance, storytelling or song, in order to pass on both sacred and secular knowledge – it is part of the 'encyclopedia' of how to be an Australian Aboriginal.
As such, it is used for teaching and communicating information and for passing on 'story' – and 'The People' (as Aboriginals sometimes call themselves) can be seen even today, sitting in a small circle in a dry river bed, drawing the story in the sand, smoothing out the sand again, and drawing another.
It has been such an intrinsic part of an Aboriginal person's communication system that even now, were you to lean down and casually trace a line in the sand, you would gain the immediate attention of any traditional Indigenous person in your company.
Read about Aboriginal Art Styles