On September 19th, 2017 we learned about

Speculation about why the ancient Greeks repeatedly rebuilt on earthquake fault lines

Despite what housing prices in the San Francisco Bay area may suggest, most people have an understanding of how dangerous living on an earthquake fault-line can be. It helps that since San Francisco’s historic quake in 1906, a lot of research has been done on what causes earthquakes, leading to more safely engineered buildings that can survive a tremblor. Of course, before people even considered the notion of plate tectonics, seismically active locations have been surprisingly active real estate markets. In fact, there’s a chance that the occasional shake-up actually attracted people, since they interpreted earthquakes as being divine in origin.

Guessing why the ground shakes

Geologist Iain Stewart from the University of Plymouth noticed an odd trend in building locations in ancient Greece, as many cities, temples and monuments were built directly on active fault lines. On it’s own that’s not that odd, but the fact that ancient people’s repeatedly rebuilt ruined structures at these locations indicates that there was a strong motivation to do so. Without scientific explanations and predictions to help shape people’s reactions, Stewart suspects that the ground’s spontaneous movement was likely understood to be an expression of the gods’ will. Even if a building was shaken to dust, knowing that a deity had taken an interest in a particular plot of land boosted its prestige as a sort of ‘holy’ site.

In some cases, the intersection of geology and faith is fairly clear. The famed Oracle of Delphi described visions that foretold the future and explained the actions of the gods. While the accuracy of those interpretations may be up for debate, a biochemical component has been found for the seer’s visions, as ethylene gas was likely produced underground, and released with each bit of seismic activity. The priestess was then probably subject to hallucinations, and would share the her descriptions of these sights as guidance for her visitors. Similarly, an oracle at Perachora Heraion may have lost their divine gift after a quake blocked off a water supply to vision-inducing hot springs in 300 BC.

Picking fault lines on purpose?

Even ignoring these more mind-altering interactions with fissures in the rock, Stewart believes that the ancient Greeks weren’t rebuilding on fault lines at random. It’s hard to move a city to avoid seismic activity, but it should have been possible to a least move a broken temple off a fault. Instead, Stewart things the Greeks rebuilt at the same locations on purpose, possibly to harness the inexplicable energy of that spot. While Stewart has a list of at least four more cities that seem conspicuously located along active fault lines, he admits that he’s looking at this from a geologist’s perspective. He’s hoping that archaeologists will look for evidence of people’s intent to build where the ground shook, helping answer how they rationalized living in such a risk-prone place.

As for the Bay Area… the weather really is lovely most of the year, and the local produce is hard to beat, plate tectonics be damned.

Source: Ancient Greeks May Have Deliberately Built Sacred Sites on Earthquake Faults by John Dyer, Seeker

On September 12th, 2017 we learned about

DNA test defies long-held assumptions by revealing that a decorated Viking warrior was, in fact, female

It’s weird when a fantasy series for kids ends up beating actual archaeologists to a historical fact. As it turns out though, thanks to characters like Astrid in the How to Train Your Dragon series, my kids are apparently more comfortable with the notion of a female Viking warrior than most scholars have been for the past 137 years. A grave in Birka, Sweden was discovered with a considerable amount of equipment suitable for a high-ranking warrior, but nobody even really considered the idea that this warrior was a woman until this year, when genetic testing firmly established her XX chromosomes.

The grave in question is known as BJ581, and is somewhat famous as an example of a successful warrior’s grave. In addition to the human skeleton, the grave also contained the bodies of a male and female horse, a sword, an axe, a spear, armor-piercing arrows, a battle knife, two shields and a board game. Many of these items have since been found to be representative of warrior burial practices in the Middle Ages, but the board game stands out. The chess-like game is thought to be a sign that this particular warrior was able, and probably expected, to have a mastery of strategy and tactics, quite likely as a commander on the battlefield. The conclusion is therefore that the occupant of grave BJ581 wasn’t not only a fighter, but a skilled and accomplished one at that.

Weapons aren’t for women?

This same collection of grave goods has long been used as evidence that this warrior was male, because people were used to that idea, more or less. Researchers from the 1880s onward have essentially assumed that anyone able to wield a weapon must be male, most likely because of researchers’ own cultural standards. In most of the studies of this grave, there was little investigation into the skeleton’s sex because it was considered a foregone conclusion. Only recently did Anna Kjellström actually investigate the sex of the body, a task made easier with modern DNA analysis. In addition to the discovery of two X chromosomes, isotope samples from the skeleton’s tooth root and upper arm also revealed that this woman had probably moved to Birka from elsewhere somewhere between ages four and nine.

As definitive as the chromosomes are in this case, there’s still push-back in the academic community to accept this correction. In some cases, people point to the idea that women may have been buried with weapons that were heirlooms, or for ceremonial purposes. Women may have been buried alongside male warriors and their weapons. People have even wanted to rewrite the meaning of the game pieces, suggesting that maybe this longstanding sign of tactical prowess was actually, after 100 years of agreement, included because the deceased might have enjoyed playing games. This is all despite other historical records pointing women’s martial abilities in Viking societies, even beyond kids’ movies and cartoons.

Accepting female fighters

The warrior from grave BJ581 isn’t the first woman to face this kind of resistance. The most famous example is probably the Scythian women more commonly known as Amazons. Famous even in their own time, myths and exaggerations created some doubt about if these warriors really did fight bows and arrows, spears and swords from horseback as written and depicted in contemporaneous artwork. Today we have the physical evidence, including genetic testing, to confirm many of these legends, and it seems that the reputation of female Viking warriors may be on a similar track. With this new knowledge from Birka, people are now wondering how many other Viking women have been misidentified in other graves, and further tests should help settle some doubts about who exactly was fighting in Viking armies.


My third grader asked: Women have smaller bones than men?

Part of what sparked the interest in testing this warrior’s skeleton’s DNA was that the bones were proportionally a bit slighter than one might expect for a male. Hips and shoulders are usually more obvious hints at a skeleton’s sex, but studies have also found that males are more likely to have slightly thicker bones, such as around the tibia.

Source: First Female Viking Warrior Proved Through DNA by Kristina Killgrove, Forbes

On August 29th, 2017 we learned about

Twisted and knotted cords found to tell tales beyond basic numerical tallies

234 years ago, Felipe Tupa Inka Yupanki arrived in the small Peruvian town of Collata to organize an uprising of native Incans against Spanish colonizers. Yupanki issued decrees and tried organizing an army, although the planned revolt came to a halt once these plans were discovered, ending in the rebel’s execution. This story isn’t as well known as the larger Incan rebellions of the eighteenth century, partially because it’s largely documented in collections of yarn and string in a writing medium called a khipu.

Recording words in twisted cords

Khipus are an Incan form of logosyllabic writing built out of twisted fibers and cords made from cotton, cloth or animal fibers like alpaca and llama hair. Shorter cords of variable color, patterning and textures are individually tied to one larger cord that acts like a sort of spine for the whole message. Each khipu is capped by a cayte, which was generally a textile like a ribbon or bandanna tied to the pieces creator, asserting its authenticity like a signature. If laid out flat, the whole khipu might resemble a short, uneven fringe, but that variability is key to their utility as a communication medium.

Many of the khipus now in museums have been found to use knots to record numbers, and were simple, portable accounting tools used by herders into the twentieth century. Unlike the beads of an abacus, knots were not directly representational of quantities, instead relying on distances and size to record different numbers. By and large, these kinds of accounting khipus were made of cotton, requiring less sophistication in their craftsmanship. However, two khipus recently studied in Collata display a new degree of depth and sophistication, showing that these objects could encode entire stories, as long as you know what to look for.

Narratives beyond numbers

The two khipus from Collata are known to reference the Incan rebellions, but they’re not really being read word for word at this point. Village elders have been passing the khipus, along with other documents tied to the town’s history, down to each other for generations, telling the story of the khipus in the process. The khipus are thought to be based on Quechua, a language no longer spoken in Collata. Still, the various twists, colors, and choices in fiber support the notion that this cords represent words, with 95 individual symbols having been identified.

Since my two sentence summary of the rebellion used 51 unique words, it’s easy to see that the khipu isn’t offering any one-to-one transcription. The 95 symbols that have been identified aren’t phonetic words, instead functioning more like rebuses or pictograms. So rather than directly represent a word, symbols that can remind someone of a word thanks to their similar sounds might be combined to express an idea. This system wouldn’t have been as flexible as a fully phonetic alphabet, but the 95 symbols seen across 487 cords on the Collata khipus are enough to have hundreds of unique combinations.

At this point, researchers speculate that these khipus may be a taste of a significant and unexplored communication system. The success of the Incan empire is hard to imagine without robust means of communication, and if more examples of narrative writing can be found, it may help unlock a lot of recorded knowledge about how that society functioned.

Source: Writing with Twisted Cords: The Inscriptive Capacity of Andean Khipus by Sabine Hyland, Current Anthropology

On August 20th, 2017 we learned about

Ancient Romans special regard for eating jar-raised rodents

For all of the foodie-themed photos people share today, the world somehow lacks gratuitous shots of dormice being served for lunch. This seems like a missed opportunity, because edible dormice were one of the original foods to brag about, with scholars and elites writing down details about how the rodents were served in lieu of selfies and filtered photos. Like the particular interests of gourmands today, this interest wasn’t because edible dormice were a staple of the ancient Roman diet, or because they were necessarily that much tastier than any other roasted mammal. Serving up dormice was a way for hosts to dazzle their guests without making a huge investment in the process.

From pot to plate

A serving of edible dormouse (Glis glis) might include honey, poppy-seeds, pepper and bits of pork. The layered flavors alone would have been impressive to a Roman audience, as more modest meals would have been heavy on salted meat or fish, as the salt was a critical preservative for less-than-fresh foods. Dormice, on the other hand, didn’t need the space or resources a pig did, and they could be raised in a villa without much fuss. The animal was placed in a ceramic pot called a gliarium, where it was fed and watered until it was ready to be eaten. With small air holes and just enough room to move around, a dormouse didn’t have much to do besides sleep and fatten up.

Once it was time to eat, the fact that dormice weren’t actually difficult to raise didn’t seem to matter much. They were apparently valued enough that supplying them could be a profitable enterprise, but not really enough to amount to more than an appetizer. Like exotic foods of today, people made notes about eating a dormouse, particularly its size as testament to the host’s wealth, but their relative scarcity clearly helped make them more intriguing than your average squirrel or rat.

Dormice in decline

Dormice aren’t on many menus anymore, but their may still be in trouble. Hazel dormice (Muscardinus avellanarius) in England are in decline, with populations dropping 70 percent in 20 years. As their absence on Instagram proves, this decline isn’t due people making them into fancy appetizers again, but larger environmental problems. Habitat loss, climate change and local woodland management are all suspected to play a role in shrinking dormouse populations in England.

Source: Dormice, ostrich meat and fresh fish: the surprising foods eaten in ancient Rome by Emma Mason, History Extra

On July 25th, 2017 we learned about

Biologists offer new ways to learn human history from old books

For as often as my family checks out books from the library, I don’t think we’ve ever brought home any northern European furniture beetles at the same time. On the other hand, some bookmakers 900 years ago probably didn’t know they were including eggs in the cover they were making from wood and deer skins, so the fauna included in any particular book might not be discovered for some time. The paperback kids’ books we often check out probably can’t hide beetles, but there’s still a lot that could be discovered on their pages. Scientists now have non-destructive ways to sample and analyze proteins, DNA and other microscopic evidence, leading to whole new set of stories is being written about about books, almost completely independent of what’s written in them.

Layers of leather

A thorough study was recently conducted of a 900-year-old copy of The Gospel of Luke. The book was made with a wooden cover bound with deer hide, although DNA analysis revealed that even the cover was more complicated than previously assumed. Aside from the wholes made by Anobium punctatum larvae, the majority of the cover was covered in skin from a Roe deer (Capreolus capreolus), while the strap to close the book was made of fallow (Dama dama) or red deer skin (Cervus elaphus). Aside from revealing a bit more sophistication in the design of the book, this also told researchers about the wildlife that must have been living in England where the book was made. It was probably during a transition where the larger red and fallow deer were beginning to eclipse the native Roe deer, a fact that was even trickling down to book making.

Vellum variety

Along similar lines, a gentle rub of a polyvinyl chloride eraser on each page was able to pick up proteins, microbes and DNA from each piece of vellum. Vellum was an early form of parchment made from the skin of young animals, and while that was the expected material to be used in a book like this, the diversity of animals used across different pages was a surprise. Instead of a homogeneous collection of calf skin, sheep and even goat skins were used to make the 156 page manuscript. Previously, goats were thought to have only been used for book making in southern Europe, and researcher wonder if the small number of goat pages in the second half of the text may have been due to a shortage of preferred materials. It also coincided closely with when the primary scribe changed, possibly indicating a bigger disruption to the book’s production before it was completed.

Tainted by touching

The paper books we encounter these days probably aren’t going to turn up with traces of deer or goats, but they are likely to have plenty of human DNA and microbes. Pages with hymns were found to have more human DNA, probably thanks to those pages being accessed, and based on the bacteria on the page, kissed, more frequently than other pages. The most common forms of bacteria on each page were Propionibacterium, which can promote acne, and Staphylococcus, which can cause staph infections if it gets under your skin. Before you worry about picking up a printed page, keep in mind that any popular technology that we put our hands on is likely to have bacteria wiped on it, including your favorite touchscreen.

Researchers have high hopes for these non-destructive ways to study old books. Understanding what lives, or lived, in a book’s pages can help with dating a book’s production, estimating the local availability of resources and even understanding who was doing the reading. A lot of history is recorded in these pages, even if it’s not the history any author intended to document.

Source: Goats, bookworms, a monk’s kiss: Biologists reveal the hidden history of ancient gospels by Ann Gibbons, Science

On July 6th, 2017 we learned about

Testing tar-based water bottles for the transmission of dangerous toxins

Keeping potable water portable has been one of humanity’s big challenges. The different flavors and smells of water are thanks to all the different materials water can pick up and carry from its containers, from stream beds to lead pipes. Some containers are more concerning than others, including some of our favorite plastics of today. As those bottles break down, small amounts of molecules like BPAs can end up in your water. As much as people are trying to avoid these contaminants today, they’re rather benign compared to the first “plastic” water bottles, which were made of something regarded as “nature’s asphalt.”

Bottled in bitumen

Bitumen is a form of petroleum that can be functionally solid at room temperature, but usually oozes like a very viscous liquid over long amounts of time. It’s composed of a variety of compounds, and can be found in a variety of natural settings, such as sandstone, bubbling up under lakes, or for the paleontologists, the La Brea Tar Pits in Los Angeles. Native American tribes living on islands of the coast of Southern California, collectively known as the Chumash, also found bitumen washing up on their beaches. The little balls of tar seep out of fissures under the ocean, and with a little work, the Chumash peoples realized that bitumen could also seal water into a container better than ceramics or skins.

The recipe for a Chumash water bottles required plant-fiber nets, pitch from trees, an abalone shell and of course a lot of bitumen. The netting was a framework to make the overall shape, which was generally bulbous with a narrow spout on the top. The shell helped provide some initial structure at the bottom, and the rest was made by slathering melted bitumen and pitch along the netting. It’s a sticky, smokey process, but researchers recently recreated it so that they could test exactly how many toxins these bitumen bottles may have been.

Safe to sip and sup?

The carefully recreated bottles were left to hold water for two months to simulate the passage of time, then tested. Mass spectrometry found that the water had picked up naphthalene, phenanthrene, and acenaphthalene, all of which can be toxic if ingested. Tests were also conducted with olive oil instead of water in order to simulate contact with other foods, since there is evidence that Chumash people ate meats and fish off bitumen-based bowls or plates. The olive oil picked up more toxins, but it may not be a perfect proxy for what the Chumash were actually eating. In the end, the most dangerous component in all these products was the smoke made during their production. That wouldn’t have harmed as many people, but anyone regularly making bitumen water bottles likely paid a price to do so.

These investigations weren’t just interested in water bottle technology. Skeletons of Chumash people from around 5,000 years ago turn up with an unusual number of health problems, including poor bone quality, smaller skulls, and bad teeth. The data from the recreated bitumen water bottles don’t fully explain these health problems, although it’s a tough connection to prove at this point. Most studies of toxicity are based around people that still have enough flesh to damage, and so there’s not a lot of information if you want to know how naphthalene might affect bones over a lifetime. Still, the amount of toxins leached into the water, oil and of course, smoke, do suggest that these water bottles contributed to health problems at a minimum.

Source: Plastic Water Bottles Might Have Poisoned Ancient Californians by Nick Stockton, Wired

On June 7th, 2017 we learned about

Moroccan fossils may force a reevaluation of when and where Homo sapiens got our start

In 1961, miners in Morocco found what appeared to be human skulls, jaws, arm and hip bones. The bones were all fossilized, but pinning down their exact age was difficult since they’d been removed from their original location. Now a second round of excavations from the same site, known as Jebel Irhoud, has uncovered more fossils, plus stone tools and crucially, charred flint from a campfire. Using a technique known as thermoluminescence with that flint, the site is now thought to have been inhabited between close to 300,000 years ago… just 100,000 years before anyone thought humans even existed.

(Im)perfect model for modernity

The idea that there were ancient hominids in Africa 300,000 years ago isn’t that shocking by itself. Other species, like Homo naledi, lived at that time too. Neanderthals had already left Africa altogether. However, the bones from Jebel Irhoud look strikingly like modern humans, and have been labeled as Homo sapiens. They’re not a perfect match though— they don’t have a modern chin, one specimen had a rather pronounced brow, and the shape of the brain case is tapered towards the back of the head. This has some anthropologists suggesting that these people were a transitional species, rather than truly modern humans, but even if that were the case, their overall similarity and age still merit some reexamination of humanity’s origins.

Overhauling our origin story

On one hand, 300,000-year-old humans may help make sense of a few things. The so-called Florisbad skull from South Africa was dated to be 260,000 years old, which made it seem like a weird outlier in the human family tree. However, if the Jebel Irhoud do represent even older members of H. sapiens, then the Florisbad skull fits into the story more neatly. Similarly, the tools found in Morocco were generally light weight, with spears that were appropriate for throwing instead of just stabbing. They’re not the only tools from this time period to have this degree of sophistication, and the thought is that if modern humans arose around 300,000 years ago, these tools might be more tightly bound to our evolution and success.

Of course, on the other hand, the location of Jebel Irhoud opens a whole host of new questions. Previously, the leading model was that H. sapiens started in Ethiopia around 200,000 years ago, with our oldest confirmed specimen dated as 195,000 years old. From that birthplace, it was though that humans started spreading out to other parts of the world, a narrative that doesn’t have space for humans to somehow be on the opposite side of the continent 100,000 years earlier. It seems that humans, or our very close ancestors, were actually spread across Africa, with no clear point of origin standing out at this point. To fill in more gaps, more fossils are needed. For better or for worse, those fossils might be all over the continent.

Source: Scientists Have Found the Oldest Known Human Fossils by Ed Yong, The Atlantic

On April 25th, 2017 we learned about

Mice moved into human homes before we could farm for food

The story of domestication sometimes sounds like a weird version of the Old Woman Who Swallowed a Fly. Dogs were domesticated to eat our leftovers. Mice moved in to eat our farmed grain, and then cats were domesticated because they ate our mice. This pets-as-digestive-tracts model has been falling apart though, because even if the logic of it seems sound, the evidence isn’t really backing it up. Dogs probably did like our scraps, but so did cats, who have never been proven to be brought indoors to actually do anything about the mice. The mice themselves may not have turned up because of our farmed food, and likely moved into human settlements before anyone knew how to farm at all.

Researchers examining archaeological sites in Israel started comparing the mouse teeth that were found at various settlements. These ancient settlements were from as far back as 200,000 years ago, and included periods when humans made houses but didn’t farm to more modern dwellings that were built when people were cultivating their own plants. On the older end of this spectrum were the Natufians, who built stone houses, buried their dead, but didn’t plant any seeds to harvest. They were somewhat comparable to the modern Masai people of Kenya, who also build settlements without growing any crops (although they don’t quite hunt-and-gather either.)

A tale of two tails

The first mouse turns up in the archaeological record 15,000 years ago. These mice were longer-tailed than their wild relatives, and quickly came to dominate the remains found in human settlements. When these settled Natufians had to become more nomadic again 3,000 years later, the mice changed too, with the long-tailed house mouse populations decreasing. These trends were reversed one more time around 11,500 years ago when people really started farming, at which point the house mice took over indoor spaces once again. These population ratios also fit with what’s found around Masai settlements. Even if the species are different, there’s a similar balancing act between indoor, long-tailed mice and outdoor mice with shorter tails.

This study doesn’t close the book on why mice came to live near people, but it suggests that growing grain wasn’t their primary motivation. Instead, it’s probably closer to the generalized scavenging made possible by being near people that attracted dogs and cats into our lives as well. As for the difference in tails, there’s a chance that a longer tailed helped the mice be more maneuverable and better escape danger, which would have been helpful when people trained their dogs to start catching them.


My second-grader said: As far as the tail-lengths go, “I have to disagree with that hypothesis.” There are lots of predators in the wild that a mouse would need to avoid, so why would being able to escape become more important inside a house?

So… yeah, it seems like a fair point. Also, some animals are known to have shorter or even detachable tails to avoid predators. A cheetah’s long tail helps it steer while it runs, but the prey they chase usually avoids long tails.

Maybe the longer tails were actually being used more like a monkey’s tail, as rats and harvest mice (Micromys minutus) have partially and fully prehensile tails, allowing them to hang on to more surfaces and crannies while maneuvering weird spaces, such as human-made shelves, boxes, etc.

Source: Mice lived with us 15,000 years ago even before farming took off by Sam Wong, New Scientist

On April 16th, 2017 we learned about

Drilled and filled cavities put dentistry’s start date in the Stone Age

5000 years ago, someone in Sumeria was worried they had “tooth worms.” It was probably just run-of-the-mill cavities, but people didn’t really know why their teeth could break down in their mouths. Lacking a real understanding of the root causes of tooth aches didn’t stop people from looking for remedies though, and people have been removing, wiring and medicating teeth for thousands of years. A discovery in Italy shows that dentistry may predate those Sumerian tooth worms though, with evidence of Stone Age fillings from nearly 13,000 years ago.

Carving for cavities

The two teeth show a lot of damage, but the assumption is that much of it was intentional. While paleolithic peoples likely demanded a lot of their teeth, using them as a third hand to hold or soften wood, hides and plants, these teeth seem to have been scraped on purpose. Instead of rough, random damage, an impressively smooth, regular pit was carved in the center of each tooth, much like your dentist would do with their drill to remove any infected tooth around a cavity and make a better seat for a filling.

Aside from the fact that this work was done without a modern dental drill, there obviously wasn’t modern fillings available either. To fill the teeth, it appears that fillings made of bitumen was used to fill the drilled hole. Bitumen is a thick, sticky substance that is usually derived from petroleum, and is most commonly used today in making asphalt cement. In Paleolithic era, bitumen was more often used as a glue in tools, but apparently dentists at the time felt it was a good way to fill in damaged teeth as well.

No signs of Novocaine

None of this sounds terribly pleasant for the patient, but a persistent tooth ache is hard to ignore. Hopefully, the dentist in question could at least recommend some of the pain-killing techniques used by Neanderthals in what is now Spain, as their teeth have turned up with traces of salicylic acid, the active ingredient in aspirin. It wouldn’t have made this a painless procedure, but it seems better than nothing.

Source: Stone Age hunter-gatherers tackled their cavities with a sharp tool and tar by Bruce Bower, Science News

On March 23rd, 2017 we learned about

Capuchin monkeys inadvertently muddle the history of human tool making

Some of the first technology created by humans were sharpened stone flakes. While they might appear to be simple rocks at first glance, archaeologists have come to note the single sharp edge and flat sides that transform these rocks into tools. The edge would have allowed early hominids to cut meat, remove skin, or work with wood and grass. To create such a tool, our ancestors are thought to have needed advanced hand-eye coordination, as well as the ability to plan the flakes’ design.

…or they would have needed to be weirdo capuchin monkeys making flakes without even noticing.

Capuchin craftsmanship

Capuchin monkeys have been observed experimenting with tool use for many years. They use rocks like shovels to dig up spiders, twigs to poke into crevices for caterpillars, and may have been cracking open cashews in a hammer-and-anvil arrangement for over 700 years. They’re one of an ever-growing list of animals that partake in at least casual tool usage, but their creativity, and perhaps dumb luck, has set them apart.

Bearded capuchins (Sapajus libidinosus) in Brazil’s Serra da Capivara National Park were observed banging rocks together, but not for the sake of getting at fruit or nuts. They were hitting pieces of quartz together with two-handed, overhead strikes, and then licking the broken stones. Researchers aren’t sure if they were trying to lick up silicon or possibly lichen to fill some sort of nutritional need, but they were sure about the stone byproducts of this activity. Many of the resulting pieces of stone were nearly identical to what has been assumed to be carefully crafted stone flakes of human ancestors. The monkeys took no notice of the fine edges or flat sides that would attract an archaeologist, but even the accidental creation of such an object is very significant.

Accident or innovation?

Sharp flakes of stone have always been assumed to be a marker of human-like intelligence and development. They were supposed to be the starting point for human artifacts, kicking off the chain of development that gives us the computer you’re reading this on. Even with other tool-using animals in the world, the sharp flakes of rock were supposed to require more deliberate creation, and were different from the broken rocks wielded by other primates like Chimpanzees and Macaques. If capuchins are making them accidentally, it means that stone flakes alone can’t be considered a reliable marker for hominid activity. Sometimes flakes have been found with other artifacts, like butchered bones or old fire pits, but on their own, we can’t be so sure we’re seeing signs of an innovative Australopithecus, or just a lucky one that wanted to lick some lichen.

In the mean time, we’ll have to watch the capuchins to see if they take notice of the utility of their flaked stones. Maybe this is a window to how specific tool creation got started in the first place?

Source: Capuchin monkeys produce sharp stone flakes similar to tools, Science Daily