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Archaeologists Change Direction in Kenya, Find World’s Oldest Known Tools

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Archaeologists surveying the Kenyan Rift Valley area quite accidentally discovered what are perhaps the oldest known stone tools in the world. They date back about 3.3 million years ago, which would make them at least 700,000 years older than what were formerly the oldest stone tools – discovered in the Ethiopian region of Hadar. So old are the most recent discoveries, that in fact they are precursors of even the earliest fossilized skulls we have of our own genus, Homo, by about half a million years. This is the exciting part. Although we’d like to think that Homo was the first to craft tools – it was actually the work of a more primitive and distant ancestor that we share.

The ancient tools might never have been discovered were it not for a happy accident. Sonia Harmand from Stony Brook University and her team were on their way to a previously uncovered fossil site at the western shore of Lake Turkana on one particular morning in July of 2011. However, the group made a wrong turn and ended up near what was then an uncharted formation of rock. The researchers quickly decided that it was an ideal enough place to harbor artifacts, decided to survey it and by the afternoon, they discovered what they were looking for. The site has been named Lomekwi 3, and giving a closer look, they managed to uncover dozens of stone age tools— including the leftover flakes from cut minerals, as well as cores and even anvils, which were discovered both at the surface, as well as below the ground. Harmand first described her team’s findings on April 14 when giving a lecture during the annual meeting of the Paleoanthropology Society in San Francisco.

“The cores and flakes we recovered are clearly knapped and are not the result of accidental or natural rock fracture,” Harmand said. “The Lomekwi 3 knappers were able to deliver sufficient intentional force to detach repeatedly series of adjacent and superposed flakes and then to continue knapping by rotating the cores.” The team was able determined the age of the tools using a relative dating technique, analyzing the area in which they had been found, between what were two layers of volcanic ash as well as a magnetic reversal of the known ages – due to the nature of continental drift and the Earth’s rotation, magnetic fields change polarity over time, and knowing these periods can help determine the age of the materials.

Another surprising feature of the Lomekwi 3 tools is that they are unusually large – much larger than the stone tools that were excavated in Ethiopia that had previously set the record for the oldest known tools, and they are in fact even larger than the rocks typically used by chimpanzees to crack apart nuts and shells, pointing to a unique transitional period in hominid technology. As described by Harmand, these preliminary observations could indicate that the Lomekwi toolmakers deliberately sought out the biggest, heaviest blocks made out of very hard raw material from local sources despite the availability of smaller blocks. They then applied a number of knapping techniques in order to remove some of the sharper edged flakes away from the core of the rocks. While the chimps, who we share a common ancestor with (and several primate species long deceased,) have been known to go on hunts, the exact purpose of the Lomekwi tools is still unclear. Chimps have been known to use spear-like objects, but the size and weight of the tools suggest another purpose.

Animal bones of the same period have been recovered from the site, perhaps conjuring up images of the ape in 2001: Space Odyssey, who realized he could use bleached tapir bones as a weapon. However, they contain no markings to indicate human activity. Evidence from another site, however, dating to the time of the tools does suggest that hominins (the group in which we, H. sapiens and our extinct relatives all fall into) were already butchering animals for food.

Back in 2010, researchers working at the dig site of Dikika, also in Ethiopia, (where the remains of Australopithecus afarensis, the three-million year-old species to which Lucy belonged, had once been uncovered), made the announcement that they had unearthed 3.4 million-year-old animal bones which showed distinctive marks, knife scrapings from where the hominins had sliced away morsels of meat from the bone with their stone tools. The claim didn’t go without a rather heated debate. Some skeptics refuted the discovery with the suggestion that any alleged cut marks were actually due to these bones being cut and trampled by the feet of passing animals. Other researchers countered that the distinct cut marks may actually have been due to the bites of crocodiles scavenging food. Although the latest discovery of tools at the Lomewki site does not necessarily prove nor disprove that hominins were responsible for making marks on the Dikika remains, it certainly is sufficient evidence to maintain that hominins close enough to be contemporaries of the Dikika nomads did in fact create implements that capable of leaving distinct cut marks.

The identity of these Lomekwi knappers remains unknown. If the manufacture of stone tools is exclusive to the Homo genus, then the evidence suggests that they may have evolved significantly earlier than what the fossil record currently suggests. A more likely scenario, however, which Harmand endorses, is that either the Australopithecus or another hominin, Kenyanthropus (which has been found nearby)— both of which have been known to have existed some 3.3 million years ago were responsible for the Lomekwi tools. Whether in fact the Kenyanthropus is actually of a distinct hominin lineage or just another type of Australopithecus still remains a point of contention, however.

Up until this point, the earliest known stone tools were considered to be derived out of the so-called Oldowan toolmaking tradition. The 20th century paleontologist Louis Leakey coined this term when he described some of the first primitive tools discovered at the Olduvai Gorge back in the 1930s. However, Harmand says that these newly discovered tools are actually different in comparison to the early Oldowan discoveries that they deserve a new name: the Lomekwian tradition.
James Sullivan
James Sullivan is the assistant editor of Brain World Magazine and a contributor to Truth Is Cool and OMNI Reboot. He can usually be found on TVTropes or RationalWiki when not exploiting life and science stories for another blog article.
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  • Archaeologists Change Direction in Kenya, Find World’s Oldest Known Tools

    • Chimps can hunt with tools, but why doesn’t it happen more often?

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    You’d think we’d know a bit more about our closest living relatives in the animal kingdom – but we’re still making surprising discoveries about chimpanzees, whose genome is about 96 percent similar to ours. While its been known for over a century that chimps are capable of making tools, it turns out that in the last few years, at least one particular tribe of the primates located in Senegal. Back in 2007, anthropologist Jill Pruetz first reported that the savanna chimps at her research site in Fongoli, Senegal, had begun using tools in order to hunt their prey. While this discovery on its own was a startling find, as Pruetz began studying them more in depth, she learned that the female chimps were the predominant hunters in the group who took up the tools.

    Due to the small sample size many dismissed the findings but Pruetz, who teaches at Iowa State University, set out to learn more. Along with her researchers, she documented well over 300 different tool-assisted hunts. This also comes on the heels of evidence that a number of primates are also capable of migrating for long distances, during which they call out to their companions to signal changes in direction. The researchers’ results were published this week in the latest issue of the journal Royal Society Open Science, and are supportive of Pruetz’s initial discoveries – that when they hunt, the female chimps will use tools more often than males will.

    Although adult male and female chimps will often hunt side by side, the males typically capture their prey by hand. Researchers, however, have observed that both the male and female chimps have made use of tools, but that in over half of the hunts – 175 versus 130 – the tools were used by females. Despite the fact that males made up roughly 60 percent of the hunting group, only about 40 percent of the hunts using tools were done by the males.

    Although the sample size was small, Pruetz suggests that there’s likely a great deal of diversity to be found when it comes to chimp behavior – factors that could easily change depending on the environment in which they’re found.

    “It’s just another example of diversity in chimp behavior that we keep finding the longer we study wild chimps,” Pruetz said. “It is more the exception than the rule that you’ll find some sort of different behavior, even though we’ve studied chimps extensively.”

    The targets of these hunts for the chimps, both male and female, were typically galagos, also known as bush babies, in the tool-assisted hunts. They’re a more primitive, nocturnal species of tree-dwelling primates. Their cries sound similar to human infants and they mark tree branches with urine, allowing them to sniff out and land on the same tree branches each time. According to Pruetz, the chimps are capable of fashioning spear-like tools that they use to jab at the animals when they spot them lurking within the cavities of trees at night. She suggests that this observable difference between how the genders hunt is that the males tend to be more optimistic when finding their quarry.

    “What would often happen is the male would be in the vicinity of another chimp hunting with a tool, often a female, and the bush baby was able to escape the female and the male grabbed the bush baby as it fled,” Pruetz said.

    Another significant question is why are only the savanna chimps found in Fongoli the only known population of non-humans that routinely stalks prey using tools. Some South American marmosets have been known to fish for clams in the Amazon and break the shells open with rocks – a learned behavior that the adults pass to their offspring, but these chimps design tools specially for the occasion. So what’s the reason? Pruetz says maybe it’s the wrong one to be asking. Instead, we should probably be asking why the chimps at other sites are not using this technique. It’s prossible that they don’t simply because that they never learned the technique, she said. Tool hunting could be the product of a gradual social tolerance that has not yet developed at the other chimp sites. Perhaps if there were a greater population of chimps, living in larger societies, they would have advanced to this capacity.

    “At Fongoli, when a female or low-ranking male captures something, they’re allowed to keep it and eat it. At other sites, the alpha male or other dominant male will come along and take the prey. So there’s little benefit of hunting for females, if another chimp is just going to take their prey item.”

    The environment could be another important factor. Pruetz noted that there was a lack of red colobus monkeys, the preferred prey for chimps found at other sites, largely due to the dry conditions found at Fongoli. The bush babies are more prevalent instead at Fongoli, and other types of prey that the female chimps are able to access with the use of tools.

    Pruetz, who is a National Geographic Emerging Explorer, has often been asked why the female’s use of tools is considered an attribute of hunting rather than one of gathering. This is a question that is reflective of the stereotypes associated with the behavior of female chimps. Chimps were first seen using sticks to “fish” for termites back in the late 19th century, but according to Pruetz, the comparison between catching ants or termites with a stick and tool-assisted hunting are superficial. The behavior of the prey and effort required by the hunter is different.

    “Fishing for termites is a very different activity than jabbing for a bush baby,” Pruetz said. “With fishing, termites grab on to a twig and don’t let go and the chimp eats the termites off the twig. When hunting, the bush baby tries to bite, escape or hide from the chimp. The chimps are really averse to being bitten by a bush baby.”

    Although a bush baby may be smaller than and not as fierce as a red colobus monkey, Pruetz maintains that this is really no different than humans preferring to hunt doves rather than deer. Ultimately, the tool-assisted hunting allows the female chimps, which could be less likely to run down their prey, access to a nutrient rich food source, according to Pruetz.
    James Sullivan
    James Sullivan is the assistant editor of Brain World Magazine and a contributor to Truth Is Cool and OMNI Reboot. He can usually be found on TVTropes or RationalWiki when not exploiting life and science stories for another blog article.