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| Diprotodon |
If you see a yamuti, then hide in a tree,” Adnyamathanha children are told, “for the Yamuti can’t lift its head to the sky.” For some Australians, learning about the Yamuti—a terrifying mythical creature that eats people and carries children away—is a rite of passage. The Adnyamathanha, one of Australia’s many aboriginal communities, have inhabited the Flinders Ranges in northern South Australia and passed down stories of the Yamuti for as long as they can remember. Some believe the myth has its origin in a long-extinct, hippo-sized mammal called the diprotodon—the largest marsupial known to have lived.
Archaeological excavation inside a recently discovered rock shelter suggests that Australia’s earliest human occupants did, in fact, interact with these giant beasts more than 40,000 years ago. But the finds in the shelter, known as Warratyi, reveal much more. They show that people traveled into the continent’s arid interior far earlier than previously thought, and were culturally and technologically more sophisticated than once believed. Warratyi, researchers say, is rewriting the history of the first Australians.
It is generally agreed that humans were well established on the Australian continent, most likely after crossing over from the Indo-Malaysian Archipelago, by 50,000 years ago. The skeleton of “Mungo Man,” found at Lake Mungo in New South Wales in 1974, dates to at least 40,000 years ago and is the oldest human skeleton found in Australia. In places such as the Madjedbebe and Nauwalabila rock shelters in the Northern Territory, humans left artifacts that are even older, but what these first Australians did next is not at all clear. Australia’s unforgivingly arid climate rapidly degrades organic materials such as wood, shell, and bone, so few locations preserve good evidence of human occupation.
The sites that have been found so far suggest that the first arrivals traveled both east and west, hugging the familiar, resource-rich coastline. There has been little evidence that they ventured into the interior, which raises doubts about whether the earliest people were capable of conquering the harsh landscape when they initiall arrived.
But that doesn’t mean they weren’t in the outback. Australia’s interior is vast and largely empty, and archaeologists have explored only a small fraction of it so far. Giles Hamm, an archaeologist at La Trobe University in Melbourne, has never been convinced of the coastal theory, and has always believed that the evidence for outback occupation is there somewhere, if only it can be found. In 2007, he teamed up with an Adnyamathanha elder, Cliff Coulthard, to search the Flinders Ranges, a rugged mountain belt 300 miles north of Adelaide, for places where early Australians might have left a trace. After excavating a couple of relatively recent occupation sites in the southern Flinders, they shifted to the north and systematically searched gorges for open sites, especially ones where sediments could accumulate and preserve artifacts and bones.
The discovery of the Warratyi rock shelter was serendipitous. While walking along a dry creek bed to respond to the call of nature, Coulthard looked up and noticed a crescent-shaped black slit high in a rugged band of rocks. He scrambled up to it and called Hamm over for a look. They found a naturally occurring shelter that looked like a cozy room perched above the bone-dry landscape. Their curiosity was immediately piqued by the blackened appearance of the ceiling. “I wondered if it could be soot,” says Hamm.
“From the moment we got there, I had a good feeling about the place,” says 63-year-old Coulthard, who has been exploring the Flinders landscape since he was a small boy. The shelter is around 12 feet deep and just high enough to stand in. More fortuitously, an ancient rockfall in front of the cave had created a small lip that allowed sediments to build up on the cave floor over the millennia. Hamm immediately saw that the floor was littered with tiny quartz flakes, evidence of tool production “When I stuck my probe into the floor and it went down almost a meter, you should have heard me yelp!” says Hamm. “It was just brilliant. And then when I pulled the probe out I could see ash, and realized that this site was special.” Hamm had no idea then how long the site had been occupied, but the proximity of a potential water source—freshwater springs nearby—made him hopeful that it had hosted at least a few thousand years of occupation.
Hamm assembled a team of excavators and experienced artifact-dating experts. They dug a pair of six-foot-long trenches in 2012 and 2013. Except for some minor disturbance from burrowing rabbits near the surface, the sediments were compacted and undisturbed. In the three tons of soil they sifted, they were able to recover an astounding 4,300 artifacts.
The very lowest level, close to the rock floor, produced only a handful of artifacts, but the story behind these finds more than made up for their scarcity. In particular, there were two fragments of burned eggshell belonging to a flightless bird called a giant malleefowl, which went extinct around 42,000 years ago, and a partial thigh bone from the massive diprotodon, which went extinct around 44,000 years ago. The animal remains were found in association with worked quartz flakes, small fragments of bone, and red ochre.
Dating deposits from the earliest stages of Australian history has been a challenge. The climate is unfriendly to the organic materials that often provide the radiocarbon used for dating. Further, in samples older than around 40,000 years, the amount of radiocarbon remaining is very small and difficult to measure, so only exceptionally well-preserved samples can provide reliable dates. Luckily, eggshell turned up at Warratyi. “Unlike in bone or charcoal, carbon preserved in eggshell is very stably locked in and unlikely to have been contaminated,” says Nigel Spooner from the University of Adelaide. The archaeologists also turned to optically stimulated luminescence of quartz in the sediments surrounding the artifacts, which measures when the mineral was last exposed to sunlight.
Taken together, the dating methods suggested that the artifacts could have been deposited in the rock shelter 49,000 years ago, not long after the first migrants to the continent arrived. “The diprotodon bone is a remarkable find,” says Chris Clarkson, an archaeologist at the University of Queensland. “And given its location—high up in a narrow rock shelter—it wouldn’t have arrived by chance. It shows a likely human association with the megafauna.”
Fossil evidence shows that megafauna such as diprotodon and the emu-like giant malleefowl roamed the Australian landscape for many tens of thousands of years before humans arrived. Exactly why the megafauna all died out around 44,000 years ago has spurred a contentious debate between those who argue that a cooling climate brought about their demise and those who believe the newly arrived humans hunted them to extinction. Unfortunately, the fragments recovered from Warratyi can’t settle this argument, since there are no cut marks on the diprotodon bone to prove that humans butchered the creature.
But there is no doubt that humans brought these things up to the rock shelter, and were living in this interior region by 49,000 years ago—nearly 10,000 years earlier than at any other interior site found to date. Diprotodon footprints preserved in the sediments of a nearby lake show that the massive marsupials were relatively common in this region when humans first arrived. “It wouldn’t be surprising if humans did hunt megafauna, and given the long gestation periods that these animals have, it would have been easy to deplete their numbers quite fast,” says Hamm. “But we don’t have sufficient evidence, so the argument remains unresolved for now.”
The stone tools recovered in association with the megafauna remains were simple, handheld blades, made from either quartz or silcrete (a hard, compacted sedimentary rock that is found locally), which Hamm thinks would have been used mainly for woodworking and perhaps for stripping plants. Some of the tools held fragments of red ochre dating to 49,000 years ago, and some held white gypsum powder dating to 40,000 years ago, showing that the tools had been used to pound rocks into a fine powder. “This is the earliest evidence for both red ochre and white gypsum use in Australia, and it is likely to have been used for body art on ceremonial occasions,” explains Hamm. Such activities point toward the presence of cohesive communities, rather than occasional groups of intrepid explorers. But what brought people to this inhospitable place, and how did they travel so far across the continent from the north coast to South Australia?
A few scrubby bushes and small trees grow near some freshwater springs, but the landscape around Warratyi today is mostly parched and dry: bare, orange-red rock and sand, as far as the eye can see. Previous analysis of climate data from lake sediments, however, shows that the Flinders Ranges were more hospitable 50,000 years ago. Cooler temperatures and more rainfall made for a lusher landscape. “There would have been many more shrubs and trees than we see today, and the entire area would have supported more wildlife,” says Hamm.
He thinks it likely that the first humans to arrive in Australia followed a string of rivers and lakes reaching southward from the Gulf of Carpentaria on the north coast. Richard Roberts, from the University of Wollongong, who has worked on some of Australia’s other early human occupation sites, agrees that this is plausible. “In many ways it is surprising we’ve never found arid interior shelters like Warratyi before,” he says, “as the climate was relatively good when the first people arrived, and interior lakes and rivers were in good nick.”
However, natural rock shelters such as Warratyi are not common in the Flinders Ranges. In this case, the crescent-shaped cave had been created by an unusual arching fold in the rocks called a syncline. The shelter would have commanded a good view of the valley, especially during wetter climate interludes when the landscape was covered with trees, and made it easier to spot game and see other people coming and going. Perhaps most important of all, the fracturing in the local rock created the freshwater springs. Although there is no evidence for long-term settlement at the shelter, numerous deposits of charcoal mixed with bone suggest that it was a popular spot to cook a meal, rest a while, and survey the landscape. “These hearths were very small, and most likely people were just roasting something little like a lizard,” explains Hamm. Meanwhile, the relatively large amount of red ochre and gypsum powder discovered there hint that it may also have been important for ceremonial purposes. “Possibly people went up there,” he says, “to paint themselves and prepare for the ceremony.”
Over the few thousand years after people first arrived in the area, the continuing good climate appears to have encouraged more to come, as evidenced by an increase in the density of artifacts in the higher, and therefore younger, sedimentary layers at Warratyi. A bone point, fashioned into a large, simple needle and dated to 38,000 years ago, suggests that people were using such tools for working animal hides—a full 10,000 years earlier than previously reported in Australia. “It is the kind of tool that might have been used to punch holes in animal hide, perhaps enabling people to make kangaroo skin bags to hold water,” Hamm speculates. Similarly, the discovery of plant resin on the edge of stone tools suggests that the occupants were attaching tools to wooden handles, a process called hafting.
Eventually the good times came to an end, and at Warratyi, a dramatic decline in artifacts around 35,000 years ago coincides with the arrival of a colder and drier climate period, when Earth felt the grip of a glacial phase. “Life in this region would have become harder as the northern monsoons stopped coming as far south, meaning that lakes and rivers dried up, vegetation dwindled, and the previously abundant sources of game diminished,” explains Hamm. But this difficult phase may have driven a period of innovation. In sediments dating to around 30,000 years ago, Hamm and his team discovered “backed” microliths, small blades with one edge blunted to allow stronger hafting—yet again 10,000 years earlier than previously recorded on the continent. “By 24,000 years ago, it would have been really tough to live in the arid zone, so it is fascinating to see these multifunctional and lightweight tools emerge,” says Clarkson, “perhaps enabling the people to adapt their hunting techniques and move around more.”
Backed microliths enabled more cunning hunting techniques. Their light weight allowed the blades to be used at a distance in projectile weapons, such as spears. And sometimes those spears could be sophisticated, containing multiple small blades, for example, that could embed in a prey animal, creating a wound that was likely to become infected, ultimately slowing the animal down. “This kind of hunting strategy would have enabled people to catch very agile animals, like the yellow-footed rock-wallaby, which moves incredibly fast,” says Hamm.
Backed microliths emerged around 70,000 years ago in South Africa, and it has been argued that they are a marker of modern humans. Others think that the small blades are more of a temporary innovation that evolved independently many times over, in multiple locations, as an adaptive response to harsher environments. “The evidence from Warratyi appears to support the adaptive-response theory,” says Clarkson.
By around 15,000 years ago the last Ice Age was on the way out in Australia, and a moister and more clement climate returned to the Warratyi region. A spike in artifacts in the rock shelter sediments from this time suggests that the friendlier weather helped the population grow again. At the site, unfortunately, rabbit burrows mix the sedimentary layers and muddy the story after that, but for the Adnyamathanha people, the shelter still feels like a direct connection with their ancestors. “Our people have always said that we’ve been here a long, long time,” says Coulthard. “And these discoveries make me feel proud for all of our people.
By Kate Ravilious in "Archaeology", USA,vol.70, nº 4, July/August 2017, excerpts pp. 49-53. Digitized, adapted and illustrated to be posted by Leopoldo Costa.
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