Australian aborigines numbered just between 1000-3000

Australia was originally settled by only 1,000 to 3,000 individuals, according to a new study, which suggests that the continent's colonisation may have been an organised affair rather than just an accident.
Aboriginal human settlers arrived in Australia some 50,000 years ago, but how many people it took to found the continent's population is unknown, researchers said.
The research, published in the journal Proceedings of the Royal Society B, suggests that about 1,000 to 3,000 individuals originally landed on Australia's shores, 'LiveScience' reported.
"This is largely speculative, but I think this suggests something more than accidental colonisation by a small group on a raft of vegetation or other unplanned voyage," researcher Alan Williams, a doctoral candidate at The Australian National University, said.

"For me, this suggests a deliberate attempt at exploration (if not migration) more akin to those we see in the recent past from Hawaii and other Pacific islands," Williams said.
It's not clear whether the original inhabitants of Australia multiplied and spread across the continent rapidly or remained small in number until the last 5,000 years or so, Williams said.

Williams used 4,575 radiocarbon dates from 1,750 sites around the continent. He assumed that more sites dating to a certain time reflected a larger population at that time.
Williams reconstructed a time-line of Australia's population in prehistory. Assuming a single wave of colonisation 50,000 years ago, he found that Australia stayed sparsely populated until about 11,000 years ago.

The population then started increasing gradually to reach a peak of about 3 million individuals 500 years ago, before declining to about 700,000 to one million individuals at the time of European contact.
Australia's population history shows a number of dips and spikes, some of which correspond with known climate changes, Williams said.
Among the most pronounced population changes is a major decline from 21,000 years ago to 12,000 years ago, when the population dropped by 60 per cent.