Stone tools discovered in central China could indicate humans left Africa hundreds of thousands of years earlier than previously believed. (CNN) — The story of human evolution may need a rewrite after 2.12-million-year-old tools were found in central China. The most ancient of these tools – a collection of hammerstones, pointed pieces and scrapers – are some 270,000 years older than what was previously thought to be the earliest evidence of human life outside Africa, according to a new paper in the journal Nature. And scientists believe there may be even older tools at the site – in Shangchen, in Shaanxi province’s Lantian county – that can’t be accessed because of farming in the area. The team that discovered the tools was led by Zhaoyu Zhu, a geologist at the Chinese Academy of Sciences. Finding suggests 8,700-mile trek In a paper published this week, Zhu and his colleagues detail how they dated the finds using a method known as paleomagnetism, which relies on changes over time in the Earth’s magnetic field. A magnetic reversal that occurred between 1.26 million and 2.12 million years ago is evident in a stone discovered at the Shangchen site, the paper states The discovery suggests ancient humans traversed vast distances earlier than previously thought – as far as 14,000 kilometers (8,700 miles), in this case – from another proposed site of early human life in East Africa, according to the study’s review in Nature. Before Zhu and his team’s discovery, the earliest concrete signs of human life outside the African continent were in Dmanisi, Georgia. These included skeletal remains and stone tools, leaving little doubt about the validity of the findings. Though the China dig did not turn up human remains, the conditions on the site are unlikely to have caused a false positive. There are no ancient rivers in the area which could have naturally produced the types of shaped stones found, and no alternative hypothesis has been put forward about how the rocks could have been formed, the Nature review states. What remains a mystery is the identity of the people who created the objects. Without skeletal remains, it is difficult to accurately link the tools to Homo erectus or another species of early human. “An early form of Homo probably made the Shangchen artifacts, but it’s too early to say if that was H. erectus,” paper co-author Robin Dennell, an archaeologist at the University of Exeter, told ScienceNews.<doc-sep>Earth is littered with evidence of intrepid, ancient peoples who had one big thing in common besides the genus Homo: they moved. Over millions of years, they spread throughout the world, leaving traces of their journey behind. Scientists are slowly closer to nailing down the details of this great migration, but every new discovery of ancient art, tools, and bones forces them to re-evaluate the story of our ancient kin. Now, a new discovery in China, described in a new Nature paper, upends our history books even further. The paper, published Wednesday, demonstrates that hominins — a group that includes modern humans, extinct human species, and our immediate ancestors — lived in Asia 200,000 years earlier than scientists previously thought. The team points to stone tools unearthed in China’s Loess Plateau as evidence. At 2.12 million years old, the tools disprove theories that early humans didn’t leave Africa until about 1.8 million years ago. The sheer age of these tools, study co-author and University of Exeter archeologist Robin Dennell, Ph.D., tells Inverse, confirms an alternative theory of human migration that’s recently gained acceptance. Ancient stone tools found in China are 2.1 million years old. Zhaoyu Zhu et. al. Dennell says he was “both surprised and not surprised” to find 2 million-year-old artifacts. “I think more people have climbed Everest than found 2 million-year-old stone tools,” Dennell says. “But I was not surprised in the sense that I think hominins started to leave Africa shortly after they learned around 2.6 million years ago how to produce sharp flakes that could be used for tasks like stripping meat off a carcass,” he explains. “This skill opened up a whole new niche for them to expand into, and that’s what I think was the trigger that enabled them to expand across Africa.” The artifacts were found in China's Loess Plateau. Wikimedia Commons Before this discovery, the oldest evidence of hominins in Asia were skeletons and artifacts found in Georgia, which were between 1.77 and 1.85 million years old. This evidence supported a narrative in which Homo erectus was the first hominin to leave Africa, colonize Asia, and later move into Europe. It was assumed that this all happened around 1.8 million years ago, which is the same age as the earliest found African specimens of H. erectus. These newly dated stone tools change that theory, suggesting that hominins had moved out of Africa before H. erectus had even emerged as a species. “Instead, the first Asians are probably an early and very primitive form of our own genus Homo,” says Dennell. “Sadly, the African fossil hominin record at 2.1 to 1.8 million years old is currently very poor, so we don’t really know much about hominins at this time.” Stone artifacts found during sampling in Shangchen. Zhaoyu Zhu et. al. While the team doesn’t know which hominins used the newly discovered tools, they note that the tools are similar to those used by other members of the Homo family in Africa at least 3 million years ago. The team analyzed 96 stone tools extracted from 17 layers of sediments and used a technique called “palaeomagnetism” to date the earth the tools were found in. The idea was that the tools are likely the same age as the layers of mud that had become encrusted around them. A fossilized H. erectus skull, discovered in the same area in 1964 at a site called Gongwangling, showed the team where in the Loess Plateau to look. Zhaoyu Zhu, Ph.D., a Chinese Academy of Sciences geologist and co-author on the new study, dated the skull to 1.63 million years old and pursued further investigations in the area. One of the reasons the Loess Plateau is such a hotbed for discovery, explains John Hawks, Ph.D., a paleoanthropologist not involved in the study, is because of its unique geological makeup. “This is a huge region of China covered by these ancient windblown sediments, called loess, and there have been many important archeological discoveries there,” Hawks tells Inverse. “I think that the systematic approach to identifying these dry time periods with large loess deposits is really important, because it is allowing scientists to tie together ancient landscapes and evaluate tools and fossils from many different sites.” Over the past several years, says Hawks, archeological finds in this area have shown that ancient human relatives have lived in this part of China in almost every time interval, from 2 million years up to recent times. China, in general, is becoming an exciting place for human evolution research — and continued exploration of the Chinese Loess Plateau will likely change up our understanding of our past even further. “This has been one of the high points in my career,” says Dennell. “It has been an absolute pleasure and privilege to work with my Chinese colleagues in such an amazing landscape as the Loess Plateau.”<doc-sep>A stone tool uncovered at the Chinese site. Image : Prof. Zhaoyu Zhu Archaeologists working in the Shangchen region of China have uncovered dozens of stone tools, the oldest of which date back 2.1 million years, making them the earliest known evidence of a human presence outside of Africa. Advertisement Ancient humans, likely a form of Homo erectus, occupied what is now the Shangchen region of China some 2.1 million years ago, according to new research published today in Nature. This area is about 400 miles (660 km) west of Shanghai, but more importantly, it’s roughly 9,000 miles (14,000 km) east of Africa, the birthplace of hominins. The discovery of 96 stone tools buried within 17 largely continuous layers of sediment, dating to between 1.3 million to 2.1 million years ago, suggests humans made their way from Africa to China longer ago than we thought. Prior to this discovery, the oldest known evidence of hominin activity outside of Africa was uncovered in Dmanisi, Georgia, namely tools and bones of a human species, possibly Homo erectus, dating back 1.85 million years. Other tools and fossils found in China and Java date back to between 1.5 million and 1.7 million years ago. But this new evidence breaks the two-million-year barrier, a first for archaeologists working outside of Africa. The astounding discovery shows that so-called “archaic humans” were romping around Asia some 1.3 million years before our species, Homo sapiens, even existed. A picture of the site. Image : Prof. Zhaoyu Zhu A team led by Zhaoyu Zhu from the Chinese Academy of Sciences in Guangzhou, China, uncovered the artifacts in the Chinese Loess Plateau. The researchers pulled out 82 flaked stone tools and 14 unflaked stones. The tools, which date back to the Early Pleistocene, were basic in their construction but diverse in terms of function, and included cores, flakes, scrapers, points, borers, picks, and hammerstones, the latter of which exhibited signs of use. Further excavations at the site revealed the lower jaw fragment of a deer, and fossils of a bovid, another cloven-hoofed herbivore, among other bone fragments. Importantly, none of the animal fossils exhibited signs of butchery, such as cut marks or deliberate breakage for accessing bone marrow, so direct evidence of animal processing was not found. The artifacts were discovered within 17 sedimentary layers. Eleven of these layers were associated with a wet and warm environment—layers which happened to contain the richest deposits of stone tools (80 to be exact). The other six layers were associated with a colder and drier environment, and they featured far fewer artifacts. Zhu and colleagues say the 17 layers span a long period, around 850,000 years, during which the region was repeatedly, though not necessarily continuously, occupied by humans, and that environmental conditions were likely an important contributor to the success and struggles of these populations. Some of the tools found at the site. Image : Zhaoyu Zhu et al., 2018/Nature Advertisement As always, it’s important to discuss how the researchers arrived at their dates. In this case, they used a technique known as paleomagnetic dating, which analyzes sediment and loess (wind-blown sand). This dating technique leverages the influence of our planet’s magnetic field when it flips, which it does from time to time, turning the magnetic north pole into the magnetic south, and vice versa. Magnetic minerals buried within sediments and loess register these polarity flips, which scientists can link to a dated reference known as the geomagnetic polarity timescale. In this case, the layers ranged in age from 1.3 million to 2.1 million years ago. Importantly, the minerals within the 17 sedimentary layers, and not the artifacts themselves, were dated, so it’s an example of “indirect” dating. It’s possible, therefore, that these artifacts aren’t as old at the dating suggests, but it’s difficult to explain how these items could otherwise have gotten there (perhaps these tools were deliberately buried, for example). Also, it’s important to point out that no fossil evidence of humans was uncovered at the site, making it impossible for the researchers to link the tools to a specific species of human. Advertisement It’s remarkable that humans were living and thriving in China two million years ago, but it’s completely within the realm of possibility. Hominins originated in Africa more than six million years ago, and the earliest tools in the archaeological record date back three million years. Writing in Nature News & Views, John Kappelman, an anthropologist at the University of Texas at Austin, explains: The roughly 14,000-kilometre [9,000 miles] trek from eastern Africa to eastern Asia represents a range expansion of dramatic proportions. The dispersal of hominins was probably facilitated by population increases as they moved into new territories and filled empty niches, and could also have been driven by the phenomenon of resource depletion that underlies the high mobility of today’s hunter-gatherers. Yet even with a dispersal rate of only 5–15 kilometres [3–9 miles] per year, a value well inside the daily foraging range of modern hunter-gatherers, the distance between Africa and Asia could have been covered in just 1,000–3,000 years. Advertisement Kappelman says further archaeological work is required to show the exact speed and route taken by these ancient humans. Katerina Harvati, head of paleoanthropology at the Senckenberg Center for Human Evolution and Paleoenvironment, likes the new study, saying the authors did a good job with their fieldwork, dating, and analysis. She said the artifacts are convincing and the use of paleomagnetic dating was appropriate. But Harvati believes there’s room for improvement, both for the geological study of the site, and in the use of other dating techniques. Advertisement “I think the work should be expanded with additional fieldwork, especially further excavations at the discovered sites,” Harvati told Gizmodo. “However, the authors have demonstrated human presence at more than two million years ago in East Asia. If the dating is correct, this would be the earliest human presence out of Africa.” Harvati says it’s surprising that hominins didn’t expand their geographic range out of Africa earlier, especially after the first appearance of stone tools some three million years ago. Advertisement “Was there a geographic or ecological barrier to dispersal, or was expansion enabled by cognitive or anatomical or cultural developments? This finding does push back such a geographic expansion, and also appears to show that human presence might have been closely linked to favourable climatic conditions,” she said. “It will help test our hypotheses about what the critical factor for early human migrations was.” No doubt, the clues to the timing of human dispersals, and the factors behind human evolution itself, likely reside within Africa. If we’re going to truly understand how and why humans were able spread across the planet, we’re going to further explore the cradle that was our first home. Advertisement [Nature]<doc-sep>
Simple stone artefacts discovered in China have prompted a re-think of early human migration. Ancient stone tools and animal bones dating back over 2 million years suggest our ancient cousins made the colossal journey into Asia hundreds of thousands of years earlier than scientists previously thought. The remains are the latest to chart the early movements of hominins – the group of ancient humans that includes our own species – as they struck out from their homelands in Africa. Recommended Finger found in Saudi Arabia reveals secrets of human migration Evidence for these early movements is thin on the ground as these first settler populations would have been small in number, but the primitive tools these creatures fashioned act as an effective “calling card” when actual bones are scarce. Now, a team led by Dr Zhaoyu Zhu at the Chinese Academy of Sciences has discovered nearly 100 stone artefacts in the country of Shangchen, which show these primitive humans living there between 1.3 and 2.1 million years ago. Previously, the earliest evidence for hominins outside Africa came from Georgia, where tools and bones belonging to Homo erectus have been unearthed dating back to around 1.85 million years. ✕ Researchers at Tel Aviv University shed new light on early modern human evolution In China and even further east in Java hominin fossils up to 1.7 million years old have been discovered, but some have claimed human activity in the region has even more ancient roots. Now, the collection of tools – potentially used to process the animal remains found nearby – provide firm evidence for these claims. “Our discovery means it is necessary now to reconsider the timing of when early humans left Africa,” said Professor Robin Dennell of Exeter University, one of the authors of the Nature study. The objects were found in a layer of Earth that spanned nearly one million years, suggesting these creatures were present in the region for a long time and during very different climate periods. Recommended Oldest human fossil outside Africa discovered in Israel Any new evidence is helpful for scientists trying to piece together the patchy history of humanity, but for now there is still much about these early migrations that remains a mystery. “The roughly 14,000-kilometre trek from eastern Africa to eastern Asia represents a range expansion of dramatic proportions,” wrote anthropologist Professor John Kappelman in a commentary on the findings. “The dispersal of hominins was probably facilitated by population increases as they moved into new territories. “Yet even with a dispersal rate of only 5-15km per year, a value well inside the daily foraging range of modern hunter-gatherers, the distance between Africa and Asia could have been covered in just 1,000–3,000 years.”