Aboriginal Australians have inhabitated the continent since at least as early as 30,000 years ago and some estimates suggest as early as 60,000 years ago and the late contact with Europeans coupled with the geographic isolation of their societies has made them some of the oldest known continual cultures on the planet.

It is believed that the Aboriginess make up one of the oldest migration groups to come out of Africa who arrived on the continent through a mixture of island hopping and migration across a land bridge between Australia and Papua New Guinea that exsisted with the lower ocean sea levels of the prehistoric world. While the archeological evidence suggest aboriginal populations came first from Southeast Asia, modern genetic testing and cultural comparisons make it rather clear that they are of a different group of peoples from those that would ultimately settle the areas of South east Asia and the indian Ocean Islands.

Due to their geographic isolation, the aborigines had little to no contact with societies outside the continent (although there is some evidence to suggest some of the most northeastern tribes had mild trade with peoples of Papua New Guinea but this claim is still disputed) so Aboriginal Australian maintained tribal bands largely focused on hunting and gathering.

While language family distribution and ethno-genetic mapping do prove unifying commonalities between aboriginal tribal cultures, it would be reductive to think of them as being part of the same cultural group. At first European contact there were at least 25 distinct ethno-linguistic groups, many of which have been lost to history due to the lack of written languages among aborigines and disinterested colonial attitudes of the 19th and 20th century.

Citations:

Romaine, Suzanne (1991). Language in Australia. Cambridge University Press. p. 27

Jared Diamond. (1997). Guns, Germs, and Steel. Random House. London. pp 314–316

Lourandos, H., Continent of Hunter-Gatherers: New Perspectives in Australian Prehistory (Cambridge University Press, 1997) p.81

Evans, R. (2007). A History of Queensland. Cambridge UK: Cambridge U. Press. pp. 10–12.