How long has Australia had people?

Over recent decades the dates have been changing on how long Aboriginal and Torres Strait Islander Peoples have inhabited Australia.

The latest accepted figures are 50,000 years, based on DNA research, and up to 65,000 years, based on archaeology.

Associate Professor Bastien Llamas from Adelaide University's Australian Centre for Ancient DNA says the gap between those dates has been steadily narrowing, as new technology comes on stream.

"Ancient DNA is any sort of DNA that you will retrieve from archaeological or paleontological sources – so old bones, if there's any DNA left in them, that's ancient DNA," he says from his office in the Darling Building, City Campus East.

"This is not so good in Australia where the climate is hot and dry or tropical. It's much easier in regions where such remains may be frozen for thousands of years.

"So, we don't have a lot of useful material to work with like that. But what we do have are populations of Aboriginal and Torres Strait Islander Peoples around Australia.”

DNA collected following appropriate ethical practices, can be used to determine how long ago ancestors of Aboriginal and Torres Strait Islander Peoples separated genetically from the preceding population of people who first came to Australia from Papua New Guinea.

Associate Professor Llamas says it’s important to be aware that Aboriginal and Torres Strait Islander Peoples have compelling stories about their Old People and origins.

“Western science – whether it be archaeology or genetics – is not meant to rewrite or invalidate traditional knowledge,” he says. “Both knowledge systems may inform each other, and they both deserve respect.

"Going back to genetics, what we do is look at genetic lineages of people living today, and then we can do a family tree on steroids, if you like, really going far back in time, not looking just at relationships between children and parents, but going back to true ancestry.

"We go back in time and try and see, for example, when did this population split from another population. So, for example when did the people from New Guinea and Australia split?

"We use mathematic modelling of genetic mutations, which occur over defined and reliable timeframes, to determine this.

Why do estimates vary?

"At this stage around 50,000 years seems to be the answer determined by this process,” Associate Professor Llamas says.

"This matches a lot of archaeological data from many sites in Australia.

"That archaeological data has changed over time from a point in the relatively recent past when scientists thought we were looking at 20,000 to 30,000 years' worth of time for the peopling of Australia.

"Then researchers started to find sites that were a little bit older, and then a little bit older, and then over time there became a consensus of about 50,000 years. This is what experts in the field call the ‘short chronology’.

"However, we have an outlier – a site in the Northern Territory at Madjedbebe (a sandstone rock shelter on Mirarr Country, Arnhem Land) where archaeological research is now suggesting a time of 65,000 years.

"It is only late last year that genetic research started to support that ‘long chronology.’ It may take some time before these new results are validated independently, but it shows how data and science continue to evolve, and in the past the DNA research and archaeological research have generally caught up with one another.

"And as we improve our datasets, we find lineages that go back further, which is why it keeps pushing the dates a little back in time.

"Of course, we will reach a point where that movement will reach a wall, where it's not going to go further back in time, and we will agree on something more definite. We haven't reached that point yet."

French-born Associate Professor Llamas notes that at either of those historic time periods, 50,000 or 65,000 years ago, Homo sapiens had not yet populated Europe, although Neanderthals had.

"The difference between 50,000 and 65,000 years, does it really matter in the end in terms of human generations?

"It's still a very long time when you consider how many generations have lived in Australia. So, the fact that the date changes and that some people criticise that we're never really 100% sure about it is okay with me."