<P> Aboriginal people mainly lived as foragers and hunter - gatherers, hunting and foraging for food from the land . Although Aboriginal society was generally mobile, or semi-nomadic, moving according to the changing food availability found across different areas as seasons changed, the mode of life and material cultures varied greatly from region to region, and there were permanent settlements and agriculture in some areas . The greatest population density was to be found in the southern and eastern regions of the continent, the River Murray valley in particular . </P> <P> There is evidence that some Aboriginal populations in northern Australia regularly traded with Makassan fishermen from Indonesia before the arrival of Europeans . </P> <P> At the time of first European contact, it is generally estimated that the pre-1788 population was 314,000, while recent archaeological finds suggest that a population of 500,000 to 750,000 could have been sustained, with some ecologists estimating that a population of up to a million or even two million people was possible . More recent work suggests that Aboriginal populations exceeded 1.2 million 500 years ago, but may have fallen somewhat with the introduction of disease pathogens from Eurasia in the last 500 years . The population was split into 250 individual "nations", many of which were in alliance with one another, and within each nation there existed separate, often related "clans", from as few as 5 or 6 to as many as 30 or 40 . Each "nation" had its own language, and a few had several . </P> <P> All evidence suggests that the section of the Australian continent now occupied by Queensland was the single most densely populated area of pre-contact Australia . </P>

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