Explained: The journey of the first Australians

The Indigenous people of Australia celebrate a culture that stretches back at least 65,000 years.

And while the evidence of such early arrival in the continent is well supported, it throws up a mystery. To date, evidence for human settlement through the lands the indigenous ancestors must have travelled is all rather more recent.

No serious researcher suggests that this apparent contradiction arises due to anything other than older evidence not yet being uncovered, but it leaves the question of the ancient route travelled very much open to conjecture.

Now, however, researchers from the Australian National University in Canberra have succeeded at least in constraining the possibilities.

In a study published in the Journal of Human Evolution, a team led by Shimona Kealy and Sue O’Connor modelled the least-cost pathway from south-east Asia to Australia at the time of the migration – a period during which sea levels were up to 50 metres below what they are today.

In doing so, the researchers found that the most frequently cited speculative route – across Indonesia and the island of Timor into what is now Australia’s Northern Territory – was less likely than thought.

Instead, they suggest a route that involves traversing islands to the north and west of the landmass known as Sahul – comprising a then-continuous Australia and Papua New Guinea.

“These people hopped their way along these islands, probably looking for a place to live where they would have access to reliable food staples and other resources – the visibility between islands would have been very favourable in terms of enabling this adventurous spirit,” says Kealy.