The evidence of early human life in Australia's arid interior

The Warratyi rock shelter in the Flinders Ranges, 550km north of Adelaide, is an impressive place.

The South Australian cave is a natural geological feature and it stands out from the surrounding ridges. It’s located in a strategic position, elevated high above the local landscape, giving it a commanding view of the gorge below.

It provides good protection from extremes of heat and cold, and Aboriginal people would no doubt have been naturally attracted to the place through the country’s history.

From the evidence we have found so far, published in Nature this month, it appears they came back repeatedly to use the site over many generations from as early as 49,000 years ago. It would have been a place of local cultural significance given the visual appearance of the cave itself.

The search for early life

This wasn’t the first site to be examined in our search for evidence of early human existence in Australia’s central region.

I had investigated a number of open sites (near the edges of creeks) in the Southern Flinders Ranges but couldn’t really get a well-stratified sequence or intact deposit good enough for excavation purposes.

I had also recorded a series of ancient rock engraving sites in the Northern Flinders Ranges, which is what actually led us to Warratyi.

Warratyi is special because it has this amazing, intact, well-layered structure with so much archaeological evidence in only a metre of deposit. It is an archaeologist’s dream to find such a site.

A rich find

We have now recovered more than 4,300 stone artefacts, 3kgs of animal bone, emu egg shell material, red ochre, white gypsum pigment, lots of plant remains and charcoal.

The deposit had lots of features such as bands of hearths (ancient fire places) around the walls of the excavation trenches, so visually we knew that the site was well occupied.

This evidence tells us that people were hunting local wildlife such as the Yellow Footed Rock Wallaby that lives in colonies around the local area, high along the ridge tops.

People were collecting emu eggs on a seasonal basis, then taking them into Warratyi and cooking them. They were collecting local bush tucker foods like Quandong (a sweet fruit like berry) and Bash Bananas as snacks.

We even have evidence of people cooking a small skink lizard called a Shingleback.

People were gathering fibrous plants and probably processing them in the shelter, perhaps to make nets to catch the Yellow Footed Rock Wallaby. We still have to prove this, but we know that this local plant was not eaten.

They were also using gypsum (white pigment like material) and red ochre very early in the site’s occupation. These pigments were probably applied to the body for ceremonial purposes and mixed with animal fats, which allowed them to better stick to the person’s body.

How ancient?

The human use of the site is dated to between 49,000 and 45,000 years ago, which shows that Aboriginal Australians settled the arid interior of the country some 10,000 years earlier than previously thought.

We found evidence of the earliest bone tool (pictured, below) in Australia dated to between 40,000 to 38,000 years ago.

This was an amazing bone tool called a uni point, probably made from the shin bone of a Yellow Footed Rock Wallaby. This would have been used to pierce the skins and hides of animals like kangaroos and wallabies, which Aboriginal people used to make skin bags for carrying water, among other things.

We found a lot of tools used for wood working and processing plant matter. These are stone flakes which have been shaped around their edges to used as cutting and shaving like tools.

We also found the earliest use of modern backed artefacts, a specialised hunting tool which was probably hafted on a composite spear, dated to between 30,000 and 24,000 years ago.

We even found evidence of the earliest use of ochre dated to 49,000 to 45,000 years ago. The ochre was more than likely painted on the body for ceremonial purposes and mixed with animal fats.

A place for survival

When people arrived at Warratyi the environment and climate would have been better than today’s more arid climate, but already it was changing. We know the big lakes were drying out and the rivers would have also been losing quite a lot of water.

By 35,000 years ago? it was becoming drier and colder, and by 24,000 years ago, the Last Glacial Maximum hyper-arid phase had well and truly arrived. This made things very challenging in terms of day to day living in the Northern Flinders Ranges.

At the Warratyi shelter there were lots of bones from a medium sized macropod which we assumed to be Yellow Footed Rock Wallaby.

This wasn’t the only macropod we found – we had Rufus Hare Wallaby, Bilby, Greater Stick nest Rat, Barred Bandicoot, Rat Kangaroo, Burrowing Bettong, Crescent Nailed Tail Wallaby and Plains Rat.

We also found a lot of small marsupial mice such as the Short Tail Hopping Mouse.

Amazingly, we found dingo bone. They are incredibly rare in Australian archaeological sites so when we find one stratified we get excited. There were also bones from a bigger kangaroo. We found some teeth of a red kangaroo as well.

There were lots of fragments of emu egg shell, many showing signs of being burnt, but no bones of the emu.

Excitingly, on some of the edges of the stone tools we also found feather barbules – the remains of bird feathers – which probably meant people were working with feathers, perhaps for ceremonial purposes.

Megafauna for food?

The main evidence of megafauna at the site, dating to around 46,000 years ago, comes from a single fragment of Diprotodon (Diprotodon optatum) radius bone.

The other evidence includes burnt eggshell from a giant extinct megapode flightless bird.

But we found no actual cut marks from tool use on the Diprotodon bone, so we can’t say for certain it was used for food. The fact that it is in direct association with other archaeological evidence at the site does makes this a very interesting find.

So this has proved to be a remarkable find, and I think there is real chance we will uncover one or two more rock shelters in the nearby area.

But whether they have the same depth of deposit, richness of archaeological finds and the same antiquity as Warratyi remains to be seen.