Dramatic shifts in the East African climate may have driven toolmaking advances and the development of trading networks among Homo sapiens or their close relatives by the Middle Stone Age, roughly 320,000 years ago. That’s the implication of discoveries reported in three papers published online March 15 in Science. 
 
 Newly excavated Middle Stone Age tools and red pigment chunks from southern Kenya’s Olorgesailie Basin appear to have been part of a long trend of climate-driven behavior changes in members of the Homo genus that amped up in H. sapiens. Locations of food sources can vary unpredictably on changing landscapes. H. sapiens and their precursors responded by foraging over larger areas with increasingly smaller tools, the researchers propose. Obsidian used for the Middle Stone Age tools came from far away, raising the likelihood of long-distance contacts and trading among hominid populations near humankind’s root. 
 
 At roughly 320,000 years old, the excavated Middle Stone Age tools are the oldest of their kind, paleoanthropologist Rick Potts and colleagues report in one of the new papers. Researchers had previously estimated that such tools — spearpoints and other small implements struck from prepared chunks of stone — date to no earlier than 280,000 to possibly 300,000 years ago. Other more primitive, handheld cutting stones made of local rock date from around 1.2 million to 499,000 years ago at Olorgesailie. Gradual downsizing of those tools, including oval hand axes, occurred from 615,000 to 499,000 years ago, a stretch characterized by frequent shifts between wet and dry conditions, the scientists say. 
 
 It’s not known whether that tool trend continued or if a sudden transition to Middle Stone Age implements happened between 499,000 and 320,000 years ago. Erosion at Olorgesailie artifact sites has destroyed sediment from that time period, leaving the nature of toolmaking during that time gap a mystery. Age estimates relied on measures of the decay of radioactive forms of argon and uranium in volcanic ash layers framing tool-bearing sediment. It’s unclear whether Homo sapiens or a closely related species made Olorgesailie’s Middle Stone Age tools, since no hominid fossils have been found there. 
 
 Back-and-forth shifts from dry to wet conditions — many happening over only a few years or decades — continued to regularly reshape the Olorgesailie landscape around 320,000 years ago, conclude Potts, of the Smithsonian Institution in Washington, D.C., and colleagues in another of the new papers. That timing coincides roughly with the emergence of H. sapiens (SN: 12/23/17, p. 24). The team’s climate reconstruction is based on microscopic and chemical analyses of the region’s soil. 
 
 A substantial number of Olorgesailie’s Middle Stone Age tools are made from obsidian that came from at least 25 to 50 kilometers away from the excavation sites. At one Olorgesailie site in particular, 42 percent of more than 3,400 stone artifacts were obsidian. Some of those finds display signs of having been attached to handles, likely as spearpoints, a group led by archaeologist Alison Brooks of George Washington University in Washington, D.C., reports in the third paper. Brooks is also a coauthor on the other studies. 
 
 Formation of trading networks among dispersed groups of H. sapiens, or possibly among closely related populations, best explains how large amounts of obsidian turned up at Olorgesailie by 320,000 years ago, contends Potts, who coauthored the third paper. “Social networking during a long period of climate variability was a key to success for early Homo sapiens,” he says. “Greater mobility encouraged inventive thinking about how to acquire resources.” Potts has long argued that H. sapiens and close evolutionary relatives evolved to deal with constantly changing environments (SN: 8/20/05, p. 116). 
 
 Still, factors other than climate fluctuations, such as hominid population declines or surges, may also have spurred ancient tool innovations to acquire more or different types of food, cautions archaeologist Yonatan Sahle of the University of Tübingen in Germany. 
 
 In addition to the obsidian tools, a total of 88 pigment lumps, including two pieces with grinding marks, came from an undetermined distance outside the Olorgesailie vicinity, Brooks’ group says. Pigment applied to one’s body or belongings may have signaled group identity or social status, the researchers suggest. 
 
 The new reports fit with genetic evidence that H. sapiens originated in Africa between 350,000 and 260,000 years ago (SN: 10/28/17, p. 16), says Stone Age archaeologist Marlize Lombard of the University of Johannesburg. Smaller, more specialized Middle Stone Age tools appearing along with pigment “provide strong indicators that by around 300,000 years ago we were well on our way to becoming modern humans in Africa,” she holds. 
 
 Ancient toolmaking approaches varied greatly from one part of Africa to another, with hominids employing diverse mixes of old-school chopping tools and newer, sharp points, says archaeologist John Shea of Stony Brook University in New York. At Olorgesailie and elsewhere, he says, “early Homo sapiens and their immediate African ancestors were at least as smart as the scientists investigating them.” 
 
 Editors’ note: This story was updated on March 21, 2018, to correct the percentage of stone artifacts made from obsidian at one Olorgesailie site. ||||| SAN FRANCISCO, CALIFORNIA—Researchers at a meeting here say they have found the oldest tools made by human ancestors—stone flakes dated to 3.3 million years ago. That’s 700,000 years older than the oldest-known tools to date, suggesting that our ancestors were crafting tools several hundred thousand years before our genus Homo arrived on the scene. If correct, the new evidence could confirm disputed claims for very early tool use, and it suggests that ancient australopithecines like the famed “Lucy” may have fashioned stone tools, too. 
 
 Until now, the earliest known stone tools had been found at the site of Gona in Ethiopia and were dated to 2.6 million years ago. These belonged to a tool technology known as the Oldowan, so called because the first examples were found more than 80 years ago at Olduvai Gorge in Tanzania by famous paleoanthropologists Louis and Mary Leakey. Then, in 2010, researchers working at the site of Dikika in Ethiopia—where an australopithecine child was also discovered—reported cut marks on animal bones dated to 3.4 million years ago; they argued that tool-using human ancestors made the linear marks. The claim was immediately controversial, however, and some argued that what seemed to be cut marks might have been the result of trampling by humans or other animals. Without the discovery of actual tools, the argument seemed likely to continue without resolution. 
 
 Now, those missing tools may have been found. In a talk at the annual meeting of the Paleoanthropology Society here, archaeologist Sonia Harmand of Stony Brook University in New York described the discovery of numerous tools at the site of Lomekwi 3, just west of Lake Turkana in Kenya, about 1000 kilometers from Olduvai Gorge. In 2011, Harmand’s team was seeking the site where a controversial human relative called Kenyanthropus platyops had been discovered in 1998. They took a wrong turn and stumbled upon another part of the area, called Lomekwi, near where Kenyanthropus had been found. The researchers spotted what Harmand called unmistakable stone tools on the surface of the sandy landscape and immediately launched a small excavation. 
 
 More tools were discovered under the ground, including so-called cores from which human ancestors struck off sharp flakes; the team was even able to fit one of the flakes back to its original core, showing that a hominin had crafted and then discarded both core and flake in this spot. The researchers returned for more digging the following year and have now uncovered nearly 20 well-preserved flakes, cores, and anvils apparently used to hold the cores as the flakes were struck off, all sealed in sediments that provided a secure context for dating. An additional 130 pieces have also been found on the surface, according to the talk. 
 
 “The artifacts were clearly knapped [created by intentional flaking] and not the result of accidental fracture of rocks,” Harmand told the meeting. Analysis of the tools showed that they had been rotated as flakes were struck off, which is also how Oldowan tools were crafted. The Lomekwi tools were somewhat larger than the average Oldowan artifacts, however. Dating of the sediments using paleomagnetic techniques—which track reversals in Earth’s magnetic field over time and have been used on many hominin finds from the well-studied Lake Turkana area—put them at about 3.3 million years old. 
 
 Although very recent research has now pushed back the origins of the genus Homo to as early as 2.8 million years ago, the tools are too old to have been made by the first fully fledged humans, Harmand said in her talk. The most likely explanation, she concluded, was that the artifacts were made either by australopithecines similar to Lucy or by Kenyanthropus. Either way, toolmaking apparently began before the birth of our genus. Harmand and her colleagues propose to call the new tools the Lomekwian technology, she said, because they are too old and too distinct from Oldowan implements to represent the same technology. 
 
 Researchers who have seen the tools in person are enthusiastic about the claim. The finds are “very exciting,” says Alison Brooks, an anthropologist at George Washington University in Washington, D.C. “They could not have been created by natural forces … [and] the dating evidence is fairly solid.” She agrees that the tools are too early to have been made by Homo, suggesting that “technology played a major role in the emergence of our genus.” 
 
 The claim also looks good to paleoanthropologist Zeresenay Alemseged of the California Academy of Sciences here, a leader of the team that found cut marks on the Dikika animal bones. (At the meeting, another team member presented new arguments for the cut marks’ authenticity.) “With the cut marks from Dikika we had the victim” of the stone tools, Alemseged says. “Harmand’s discovery gives us the smoking gun.” ||||| Scientists Are Amazed By Stone Age Tools They Dug Up In Kenya 
 
 Enlarge this image toggle caption Jay Reed/NPR Jay Reed/NPR 
 
 Our ancestors in Kenya's Southern Rift Valley made some pretty innovative tools. And they made them far earlier than previously thought. 
 
 The oldest innovations were axes designed to be held in the palm of the hand. They were shaped like a tear drop, with a rounded end and a pointed eye. The edges were wavy and sharp. And they look as if they were great at chopping down branches — or chopping up the carcass of a large animal. 
 
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 "I think of the hand axes as the Swiss army knife of the Stone Age," says paleoanthropologist Rick Potts, director of the Human Origins program at the Smithsonian Museum of Natural History and one of the lead scientists in a new study by a team of international scientists. 
 
 The researchers also found that the next technological revolution, marking the beginning of the Middle Stone Age happened tens of thousands of years earlier than previously thought. 
 
 And the researchers think that long periods of stress from repeated earthquakes and cycles of drought and heavy rains may have pushed these early humans to partner up with neighboring communities to come up with ways to cope. 
 
 toggle caption Jay Reed 
 
 The team was digging in a region called Olorgesailie in southern Kenya, an area filled with layers of sediment dating back 1.2 million years. The oldest stone tools discovered there are characteristic of what's called the Acheulian culture of the Early Stone Age and consisted mostly of the hand axes. 
 
 Enlarge this image toggle caption Human Origins Program/Smithsonian Human Origins Program/Smithsonian 
 
 In addition to branch- and carcass-chopping, the axes were likely used to dig for water to drink or tubers to eat. The carcasses probably belonged to large animals like the giant (now extinct) ancestors of hippos, elephants and wild pigs that roamed the grasslands back then. Potts says the ancient humans of that time likely scavenged dead animals, as their heavy, clunky hand axes wouldn't have served well for hunting big game. "These are very large tools," he says. "They might have been thrown but not very accurately." 
 
 toggle caption Jay Reed/NPR 
 
 Nevertheless, these hand axes served the ancient humans well for several hundred thousand years — from 1.2 million years ago to 500,000 years ago — and the technology remained largely unchanged during the time. 
 
 But around 320,000 years ago, the ancient humans seem to have switched to an entirely new technology. The scientists found numerous smaller, flatter, sharper stone tools. 
 
 "We see a smaller technology, a more diverse series of stone tools," says Potts. These tools were designed for specific purposes — some were used as blades, some as scrapers or spear heads. The scientists report their findings in three new studies published Thursday in the journal Science. 
 
 "In Olorgesailie, you have the only record of the last million years in Africa," says Marta Mirazon Lahr, a paleoanthropologist who wasn't involved in the new study. And it's "the earliest ever documented Middle Stone Age in the whole continent." 
 
 The new studies also show that by 320,000 years ago this technology was well established in the region, suggesting that human ancestors likely started developing it even earlier, she says. 
 
 "The technology they have is not a crude, early version of the Middle Stone Age. It is the full-blown Middle Stone Age," Lahr says. "They have stone tools that are small, that are prepared and retouched, that are made with technique thought to come hundreds of thousands of years later." 
 
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 The diversity of stone tools from the Middle Stone Age suggests advanced thinking and planning. "The flakes are being much more carefully prepared for a particular purpose," says Alison Brooks, an anthropologist at George Washington University and an author of the three studies. 
 
 "They are fairly small in size, compared to the technology of earlier people. And in addition, they are made with much finer grained material," which allowed them to better control shapes and sizes of the stone tools. 
 
 "We see the ability to produce small triangular points, that look like they were projectile points," says Potts. "They were tapered at the end, so that could have been put on the shaft of something that flew through the air." In other words, a potentially lethal spear. 
 
 So our ancestors likely shifted from scavenging to hunting. An analysis of the fossilized animal bones found in the sediments show that people in that period were eating a range of mammals — which were by now much smaller, and closer in size to the animals of today — including hares, rabbits and springbok and even a couple of species of birds and fishes, says Brooks. 
 
 And they weren't just picking up nearby stones to create their weapons. Earlier hand axes were made primarily from volcanic basalt, sourced within 2 to 2.5 miles of where these humans lived. The latter weapons were made of stones like obsidian, which originated far from Olorgesailie. 
 
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 "That black obsidian, that rare rock was being transported, brought in in chunks, from 15 to 30 miles away," says Potts. "We have a couple of rocks that were brought from up to 55 miles away." 
 
 These distances are far greater than what modern-day hunter gatherers travel over the course of a year, he says. 
 
 "They weren't just traveling long distances and chipping rocks as they go," he adds. "If they did that, then there would have just been small chips of obsidian left at the archaeological sites where we dig. Instead we see large pieces of raw material coming in. The rocks were shaped at Olorgesaile itself." 
 
 That kind of exchange of raw materials is a tell-tale sign of exchange between different groups of people, the scientists say. "In the Middle Stone Age, we begin to see the early stages of social networks, of being aware of another group and exchanging rocks over longer distances." 
 
 Potts and his colleagues also find evidence of exchange of brightly colored red and black rocks that were then drilled into, possibly to extract pigment. This is the earliest evidence of the extraction of pigments, says Lahr. 
 
 It's also evidence of a complex culture, where the ancient humans probably used pigments symbolically — perhaps to paint themselves, or their hides, or weapons. And where different groups exchanged raw materials (and possibly food). 
 
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 There's that same kind of exchange today, says Brooks, referring to hunter gatherer groups like the Hadza people of northern Tanzania. 
 
 "They deliberately maintain distant contacts with people in these other groups," she says. They have strategies to maintain these contacts — either by encouraging their children to marry into these other groups, or they take trips to visit the groups, to maintain ties by giving gifts. "It's a way of building up these distant contacts, which are extremely important for their survival." 
 
 During times of stress, when food or water is scarce, people from one group can disperse and take shelter with other groups that they've cultivated a relationship with. "So the networks are like money in the bank, or wheat in your silo or cows in your barn," says Brooks. "They don't have any other way of saving for a rainy day." 
 
 And as she and her colleagues show, the beginning of the Middle Stone Age in Kenya was preceded by a long and tumultuous phase in the region. 
 
 "Things were going haywire, in terms of the development of geological faults, earthquake activity that moved the low places high and the high places low," says Potts. "It changed the shape of the landscape." This was accompanied by repeated cycles of droughts and high rainfall. 
 
 "And it is precisely during those time periods that we expect to see hunting and gathering people to move further distances," says Potts, "and to begin to nurture relationships with groups beyond their own group." 
 
 It is no different than what humans all over the world do today, he adds. When times are tough, we look for greener pastures. The archaeological records from the Middle Stone Age at Olorgesailie reveal "the roots of that kind of migration," he says. ||||| Stone tools now 3.3 million years old 
 
 Sonia Harmand presented a talk at the Paleoanthropology Society meeting this week describing her team’s discovery of stone tools in a 3.3-million-year-old context at Lomekwi, on the west side of Lake Turkana. Michael Balter reported on the talk in a story in Science: “World’s oldest stone tools discovered in Kenya”: 
 
 In 2011, Harmand’s team was seeking the site where a controversial human relative called Kenyanthropus platyops had been discovered in 1998. They took a wrong turn and stumbled upon another part of the area, called Lomekwi, near where Kenyanthropus had been found. The researchers spotted what Harmand called unmistakable stone tools on the surface of the sandy landscape and immediately launched a small excavation. 
 
 The story discusses the contents of the talk, that the tools have been found both from surface and excavation contexts. According to the article, the artifacts show quantitative differences from known Oldowan assemblages, all of which are at least 700,000 years more recent. These differences led Harmand and colleagues to name a new tradition, which they are calling the “Lomekwian”. 
 
 I can’t really comment more informatively about this until the work is published so that I can evaluate it. The obvious implication is that stone tools were invented and used by multiple lineages of early hominins. Just as there were different styles of body shape and bipedal mechanics among early hominins, there were likely different styles of technical traditions. A few of these were stone, but almost certainly there were perishable tool traditions among most populations of early hominins. Just taking what we know from living chimpanzee populations, with different traditions of tool use, complex tool sets made from perishable materials, and occasional use of durable objects made from stone. All hominins added initially was the deliberate flaking of stone to make objects recognizable in the archaeological record. 
 
 That is to say, humans have elaborated upon a technical ability that is latent among all the apes. This technical ability rests upon social learning skills that are necessary in chimpanzee societies, and early hominin societies inherited those skills from the common ancestors of humans and chimpanzees. After millions of years of exploring this technical space, some experiments led to the manufacture of stone flakes and choppers. Possibly one or more experiments led to the manufacture of bone points or piercers, as evidenced at Swartkrans and Kromdraai, and often attributed to robust australopithecines. 
 
 Such traditions may or may not have been shared across different hominin populations. In chimpanzees, technical traditions are not widely shared, yet we know that they may last locally for at least a few thousand years. If a chimpanzee-like model applied across the Pliocene, traditions that lasted a few thousand years across local areas would occasionally be visible to archaeologists, if they were looking for them. 
 
 Now they are.
– For decades, the human story was one told through signs of modernity—art, tools, burials—found only after Homo sapiens left Africa. Recent discoveries pushing back the date of departure are helping to change that narrative, as are three new studies in Science. Together, they describe the earliest stone tools of their kind in East Africa as well as the earliest evidence for long-distance transport of raw materials in the region, per Science News. Researchers previously believed the Early Stone Age marked by large, primitive tools (hand axes and cleavers) made way for the Middle Stone Age and its smaller tools (spearpoints and blades) around 280,000 years ago. But stone tools found in Kenya's Olorgesailie Basin show hominin groups—it's not clear which species is responsible—had developed these more advanced tools approximately 320,000 years ago. "We see a smaller technology, a more diverse series of stone tools … designed for specific purposes," researcher Rick Potts tells NPR. An expert not involved in the study says the tools are so "prepared and retouched" they suggest the Middle Stone Age likely started even earlier. What drove it? Microscopic and chemical analyses of the region's soil show the landscape was rapidly shifting between wet and dry conditions, meaning hominins might have been forced to adapt. But as the technology also coincides with the emergence of Homo sapiens in Africa, it's possible that the human mind deserves credit. The tools themselves suggest the development of trading networks, too. Some were made of rocks carried from 55 miles away, says Potts. Others were made of obsidian from as far as 30 miles away, per the Conversation. (These stone tools are also making waves.)