Our ancestors were pioneers of colonisation

SYDNEY - Archaeological investigation of campsites up to 50,000 years old in Papua New Guinea gives a glimpse of how highly adaptable humans at the forefront of global colonisation were.

University of Otago anthropologist Prof Glenn Summerhayes and colleagues indicated that as early as 49,000 years ago, groups were regularly moving back and forth through extremely rugged territory to exploit rich plant food resources in Papua New Guinea’s Ivane Valley, 2,000 metres above sea level.

The archaeological work reveals campsites buried by volcanic ash where people made stone tools, hunted small animals and gathered the high energy nuts of the local Pandanus trees in conditions much colder than the present day.

The sites were occupied during a relatively warm phase of the last ice age — the Pleistocene — when New Guinea was joined to Australia as part of the continent of Sahul, reports the journal Science.

Prof Summerhayes, who led the team of archaeologists from Otago, Australia and Papua New Guinea, says the stone tools they found, known as waisted axes, suggest colonists were deliberately modifying the valley landscape.

They wanted to clear forest patches to promote the growth of useful plants such as Pandanus, says an Otago release.

Our findings paint a picture of a highly mobile society that quickly adapted to and survived in a radically different environment to the coastal regions they had recently arrived from.

“It is remarkable that this is occurring around 15,000 years before other modern humans would colonise Europe, Prof Summerhayes says.

As well as using tools to engage in agro-forestry, state-of-the-art analysis of starch residues on the waisted axes suggest that yams were being brought to the valley as food supplies from the lower altitudes where they grew, he says.

All this is unprecedented evidence of careful, intentional colonisation over thousands of years, rather than people just wandering around foraging and moving on.”