The first humans arrived in Australia up to 15,000 years earlier than previously thought, scientists have announced.
During excavations of the Madjedbebe rock shelter in northern Australia, researchers have found thousands of artefacts, including stone tools, grinding stones and hatchets, showing humans must have been at the site at least 65,000 years ago.
The findings, published in Nature, have major implications for our understanding of early human migration beyond Asia, why Australia’s megafauna went extinct, and, potentially, if these early humans interacted with Homo floresiensis, the mystery “hobbit-like” species found only on the Indonesian island of Flores.
Madjedbebe is one of the key sites when it comes to the debate of when humans first arrived in Australia. It was first discovered in the 1970s and excavations have taken place at the site ever since. Initial reports indicated human presence in Australia from between 50,000 and 60,000 years ago, but these findings were highly contentious due to questions over the dating techniques used.
At present, estimates for mankind’s arrival in Australia range from between 47,000 and 60,000 years.
Now, however, researchers have excavated thousands more artefacts from Madjedbebe, providing new and robust evidence for when the site was occupied by humans. During the dig, archaeologists found around 11,000 artefacts and matched them to the age of the sediments in which they were found. By doing this, they were able to accurately date them—showing the oldest artefacts were around 65,000 years old.
Lead author Chris Clarkson tells Newsweek: “I have no concerns the dates are incorrect. We have dated thousands of sand grains from dozens of samples across the site and the results show very accurate ages with little mixing.”
He says the artefacts are in good positions, with broken ones not falling between different layers of sediment. “Furthermore, at the front of the shelter there is a dense concentration of rockfall which traps the artefacts in place,” he continues. “These show nice lenses of artefacts that are indicative of numerous episodes of occupation and cannot have moved since the site formed.”
It is thought the first Homo sapiens left Africa around 100,000 years ago, reaching Asia around 70,000 years ago and moving through Egypt and into the Negev Desert. The latest discovery indicates humans made a fairly speedy journey to Australia.
“New Guinea and Australia were joined at this time of very low sea levels, so they could have entered the continent through either Australia or New Guinea or both,” Clarkson says. “Once they had crossed the ocean gaps they could have walked across the intervening land bridge and all the way to Tasmania.”
This early arrival would have meant humans lived alongside Australia’s megafauna, which included a car-sized wombat and a 6,600 lb marsupial, for up to 20,000 years. Scientists do not know exactly why these huge creatures went extinct, but one theory has been that human arrival in Australia played a role in their demise.
The new date of human occupation contradicts this theory. Pushing back the age of first Aboriginal occupation to 65,000 years ago lengthens the period of co-existence of humans and megafauna considerably to perhaps 25,000 years or greater,” Clarkson says. “This makes it extremely unlikely that humans rapidly wiped out all of these large animals. It was a gradual process and the end of a very long process of faunal extinctions in this country, more likely linked to climate change. Humans may however have had some small role, though we have no direct evidence for this.”
It also means humans may have been in contact with H. floresiensis. This extinct species from the Homo genus was first discovered on Flores in 2003. They were dubbed “hobbits” as they stood at just 1.1 meters in height. For many years, scientists debated whether they had evolved separately and somehow ended up on Flores, or if it evolved from Homo erectus—becoming much smaller due to limited resources. Some scientists suggested it was a deformed human.
Scientists now largely agree H. floresiensis likely came from an early ancestor from Africa and was not connected to H. erectus, as previously thought. This species, however, lived between 50,000 and 190,000 years ago—meaning the first humans in Australia may have come across them at some point.
“It means humans and Homo floresiensis co-existed in the Island Southeast Asia region for thousands of years, but we have no idea if they made contact or not,” Clarkson says. “Humans may have skirted islands on which floresiensis was living. We don't know at this stage if modern humans eventually brought about their demise or not.”
Researchers now plan to re-excavate other archaeological sites in the region to see if they can duplicate the ages seen at Madjedbebe. “Similar kinds of artefacts are known from the base of these sites, so it is very likely they also date to 65,000 years ago,” he says.
In a related News & Views article, Curtis Marean, from Arizona State University, said the findings remind us that Australia “could reveal many other secrets” that will increase our understanding of human colonization and its impact on the environment.
“We now know that modern humans, after they left Africa around 70,000 years ago, dispersed rapidly to a coastal area that became the departure gate for their journey to Australia,” he wrote. “From that launch pad, perhaps some of them envisaged other lands across the water that they could not see. They decided to take a chance and built boats, loading them with both new and tested technologies. Then, with their families, they boarded to embark on a journey of discovery. Sounds familiar—sounds like humans reaching for the stars.”
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