Archaeology

we’ve-had-a-denisovan-skull-since-the-1930s—only-nobody-knew

We’ve had a Denisovan skull since the 1930s—only nobody knew


It’s a Denisovan? Always has been.

After years of mystery, we now know what at least one Denisovan looked like.

A 146,000-year-old skull from Harbin, China, belongs to a Denisovan, according to a recent study of proteins preserved inside the ancient bone. The paleoanthropologists who studied the Harbin skull in 2021 declared it a new (to us) species, Homo longi. But the Harbin skull still contains enough of its original proteins to tell a different story: A few of them matched specific proteins from Denisovan bones and teeth, as encoded in Denisovan DNA.

So Homo longi was a Denisovan all along, and thanks to the remarkably well-preserved skull, we finally know what the enigmatic Denisovans actually looked like.

Two early-human skulls against a black background.

Credit: Ni et al. 2021

The Harbin skull (left) and the Dali skull (right).

Unmasking Dragon Man 

Paleoanthropologist Qiang Ji, of the Chinese Academy of Sciences, and colleagues tried to sequence ancient DNA from several samples of the Harbin skull’s bone and its one remaining tooth, but they had no luck. Proteins tend to be hardier molecules than DNA, though, and in samples from the skull’s temporal bone (the ones on the sides of the head, just behind the cheekbones), the researchers struck pay dirt.

They found fragments of a total of 95 proteins. Four of these had variations that were distinct to the Denisovan lineage, and the Harbin skull matched Denisovans on three of them. That’s enough to confidently say that the Harbin skull had belonged to a Denisovan. So for the past few years, we’ve had images of an almost uncannily well-preserved Denisovan skull—which is a pretty big deal, especially when you consider its complicated history.

While the world is now aware of it, until 2021, only one person had known what the skull looked like since its discovery in the 1930s. It was unearthed in Harbin, in northeast China, during the Japanese occupation of the area. Not wanting it to be seized by the occupying government, the person who found the skull immediately hid it, and he kept it hidden for most of the rest of his life.

He eventually turned it over to scientists in 2018, who published their analysis in 2021. That analysis placed the Harbin skull, along with a number of other fossils from China, in a distinct lineage within our genus, Homo, making them our species’ closest fossil relatives. They called this alleged new species Homo longi, or “Dragon Man.”

The decision to classify Homo longi as a new species was largely due to the skull’s unique combination of features (which we’ll discuss below). But it was a controversial decision, partly because paleoanthropologists don’t entirely agree about whether we should even call Neanderthals a distinct species. If the line between Neanderthals and our species is that blurry, many in the field have questioned whether Homo longi could be considered a distinct species, when it’s even closer to us than the Neanderthals.

Meanwhile, the 2021 paper also left room for debate on whether the skull might actually have belonged to a Denisovan rather than a distinct new species. Its authors acknowledge that one of the fossils they label as Homo longi had already been identified as a Denisovan based on its protein sequences. They also point out that the Harbin skull has rather large molars, which seem to be a common feature in Denisovans.

The paper’s authors argued that their Homo longi should be a separate branch of the hominin lineage, more closely related to us than to Denisovans or Neanderthals. But if the Harbin skull looked so much like Denisovan fossils and so little like fossils from our species, the alleged relationship begins to look pretty dubious. In the end, the 2021 paper’s authors dodged the issue by saying that “new genetic material will test the relationship of these populations to each other and to the Denisovans.”

Which turned out to be exactly what happened.

A ghost lineage comes to life

Denisovans are the ghost in our family tree. For scientists, a “ghost lineage” is one that’s known mostly from genetic evidence, not fossils; like a ghost, it has a presence we can sense but no physical form we can touch. With the extremely well-preserved Harbin skull identified as a Denisovan, though, we’re finally able to look our “ghost” cousins in the face.

Paleogeneticists have recovered Denisovan DNA from tiny fragments of bone and teeth, and even from the soil of a cave floor. Genomics researchers have found segments of Denisovan DNA woven into the genomes of some modern humans, revealing just how close our two species once were. But the handful of Denisovan fossils paleoanthropologists have unearthed are mostly small fragments—a finger bone here, a tooth there, a jawbone someplace else—that don’t reveal much about how Denisovans lived or what they looked like.

We know they existed and that they were something slightly different from Homo sapiens or Neanderthals. We even know when and where they lived and a surprising amount about their genetics, and we have some very strong hints about how they interacted with our species and with Neanderthals. But we didn’t really know what they looked like, and we couldn’t hope to identify their fossils without turning to DNA or protein sequences.

Until now.

Neanderthals and Denisovans probably enjoyed the view from Denisova Cave, too. Credit: loronet / Flickr

The face of a Denisovan

So what did a Denisovan look like? Harbin 1 has a wide, flattish face with small cheekbones, big eye sockets, and a heavy brow. Its upper jaw juts forward just a little, and it had big, robust molars. The cranium itself is longer and less dome-like than ours, but it’s roomy enough for a big brain (about 1,420 millimeters).

Some of those traits, like the large molars and the long, low cranium, resemble those of earlier hominin species such as Homo erectus or Homo heidelbergensis. Others, like a relatively flat face, set beneath the cranium instead of sticking out in front of it, look more like us. (Early hominins, like Australopithecus afarensis, don’t really have foreheads because their skulls are arranged so their brains are right behind their faces instead of partly above them, like ours.)

In other words, Harbin’s features are what paleoanthropologists call a mosaic, with some traits that look like they come from older lineages and some that seem more modern. Mosaics are common in the hominin family tree.

But for all the detail it reveals about the Denisovans, Harbin is still just one skull from one individual. Imagine trying to reconstruct all the diversity of human faces from just one skull. We have to assume that Densiovans—a species that spanned a huge swath of our planet, from Siberia to Taiwan, and a wide range of environments, from high-altitude plateaus in Tibet to subtropical forests—were also a pretty diverse species.

It’s also worth remembering that the Harbin skull is exactly that: a skull. It can’t tell us much about how tall its former user was, how they were built, or how they moved or worked during their life. We can’t even say for sure whether Harbin is osteologically or genetically male or female. In other words, some of the mystery of the Denisovans still endures.

What’s next?

In the 2021 papers, the researchers noted that the Harbin skull also bears a resemblance to a 200,000- to 260,000-year-old skull found in Dali County in northwestern China, a roughly 300,000-year-old skull found in Hualong Cave in eastern China, and a 260,000-year-old skull from Jinniushi (sometimes spelled Jinniushan) Cave in China. And some fossils from Taiwan and northern China have molars that look an awful lot like those in that Tibetan jawbone.

“These hominins potentially also belong to Denisovan populations,” write Ji and colleagues. That means we might already have a better sample of Denisovan diversity than this one skull suggests.

And, like the Harbin skull, the bones and teeth of those other fossils may hold ancient DNA or proteins that could help confirm that intriguing possibility.

Science, 2023 DOI: 10.1126/science.adu9677 (About DOIs).

Photo of Kiona N. Smith

Kiona is a freelance science journalist and resident archaeology nerd at Ars Technica.

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research-roundup:-7-stories-we-almost-missed

Research roundup: 7 stories we almost missed


Ping-pong bots, drumming chimps, picking styles of two jazz greats, and an ancient underground city’s soundscape

Time lapse photos show a new ping-pong-playing robot performing a top spin. Credit: David Nguyen, Kendrick Cancio and Sangbae Kim

It’s a regrettable reality that there is never time to cover all the interesting scientific stories we come across each month. In the past, we’ve featured year-end roundups of cool science stories we (almost) missed. This year, we’re experimenting with a monthly collection. May’s list includes a nifty experiment to make a predicted effect of special relativity visible; a ping-pong playing robot that can return hits with 88 percent accuracy; and the discovery of the rare genetic mutation that makes orange cats orange, among other highlights.

Special relativity made visible

The Terrell-Penrose-Effect: Fast objects appear rotated

Credit: TU Wien

Perhaps the most well-known feature of Albert Einstein’s special theory of relativity is time dilation and length contraction. In 1959, two physicists predicted another feature of relativistic motion: an object moving near the speed of light should also appear to be rotated. It’s not been possible to demonstrate this experimentally, however—until now. Physicists at the Vienna University of Technology figured out how to reproduce this rotational effect in the lab using laser pulses and precision cameras, according to a paper published in the journal Communications Physics.

They found their inspiration in art, specifically an earlier collaboration with an artist named Enar de Dios Rodriguez, who collaborated with VUT and the University of Vienna on a project involving ultra-fast photography and slow light. For this latest research, they used objects shaped like a cube and a sphere and moved them around the lab while zapping them with ultrashort laser pulses, recording the flashes with a high-speed camera.

Getting the timing just right effectively yields similar results to a light speed of 2 m/s. After photographing the objects many times using this method, the team then combined the still images into a single image. The results: the cube looked twisted and the sphere’s North Pole was in a different location—a demonstration of the rotational effect predicted back in 1959.

DOI: Communications Physics, 2025. 10.1038/s42005-025-02003-6  (About DOIs).

Drumming chimpanzees

A chimpanzee feeling the rhythm. Credit: Current Biology/Eleuteri et al., 2025.

Chimpanzees are known to “drum” on the roots of trees as a means of communication, often combining that action with what are known as “pant-hoot” vocalizations (see above video). Scientists have found that the chimps’ drumming exhibits key elements of musical rhythm much like humans, according to  a paper published in the journal Current Biology—specifically non-random timing and isochrony. And chimps from different geographical regions have different drumming rhythms.

Back in 2022, the same team observed that individual chimps had unique styles of “buttress drumming,” which served as a kind of communication, letting others in the same group know their identity, location, and activity. This time around they wanted to know if this was also true of chimps living in different groups and whether their drumming was rhythmic in nature. So they collected video footage of the drumming behavior among 11 chimpanzee communities across six populations in East Africa (Uganda) and West Africa (Ivory Coast), amounting to 371 drumming bouts.

Their analysis of the drum patterns confirmed their hypothesis. The western chimps drummed in regularly spaced hits, used faster tempos, and started drumming earlier during their pant-hoot vocalizations. Eastern chimps would alternate between shorter and longer spaced hits. Since this kind of rhythmic percussion is one of the earliest evolved forms of human musical expression and is ubiquitous across cultures, findings such as this could shed light on how our love of rhythm evolved.

DOI: Current Biology, 2025. 10.1016/j.cub.2025.04.019  (About DOIs).

Distinctive styles of two jazz greats

Wes Montgomery (left)) and Joe Pass (right) playing guitars

Jazz lovers likely need no introduction to Joe Pass and Wes Montgomery, 20th century guitarists who influenced generations of jazz musicians with their innovative techniques. Montgomery, for instance, didn’t use a pick, preferring to pluck the strings with his thumb—a method he developed because he practiced at night after working all day as a machinist and didn’t want to wake his children or neighbors. Pass developed his own range of picking techniques, including fingerpicking, hybrid picking, and “flat picking.”

Chirag Gokani and Preston Wilson, both with Applied Research Laboratories and the University of Texas, Austin, greatly admired both Pass and Montgomery and decided to explore the underlying the acoustics of their distinctive playing, modeling the interactions of the thumb, fingers, and pick with a guitar string. They described their research during a meeting of the Acoustical Society of America in New Orleans, LA.

Among their findings: Montgomery achieved his warm tone by playing closer to the bridge and mostly plucking at the string. Pass’s rich tone arose from a combination of using a pick and playing closer to the guitar neck. There were also differences in how much a thumb, finger, and pick slip off the string:  use of the thumb (Montgomery) produced more of a “pluck” compared to the pick (Pass), which produced more of a “strike.” Gokani and Wilson think their model could be used to synthesize digital guitars with a more realistic sound, as well as helping guitarists better emulate Pass and Montgomery.

Sounds of an ancient underground city

A collection of images from the underground tunnels of Derinkuyu.

Credit: Sezin Nas

Turkey is home to the underground city Derinkuyu, originally carved out inside soft volcanic rock around the 8th century BCE. It was later expanded to include four main ventilation channels (and some 50,000 smaller shafts) serving seven levels, which could be closed off from the inside with a large rolling stone. The city could hold up to 20,000 people and it  was connected to another underground city, Kaymakli, via tunnels. Derinkuyu helped protect Arab Muslims during the Arab-Byzantine wars, served as a refuge from the Ottomans in the 14th century, and as a haven for Armenians escaping persecution in the early 20th century, among other functions.

The tunnels were rediscovered in the 1960s and about half of the city has been open to visitors since 2016. The site is naturally of great archaeological interest, but there has been little to no research on the acoustics of the site, particularly the ventilation channels—one of Derinkuyu’s most unique features, according to Sezin Nas, an architectural acoustician at Istanbul Galata University in Turkey.  She gave a talk at a meeting of the Acoustical Society of America in New Orleans, LA, about her work on the site’s acoustic environment.

Nas analyzed a church, a living area, and a kitchen, measuring sound sources and reverberation patterns, among other factors, to create a 3D virtual soundscape. The hope is that a better understanding of this aspect of Derinkuyu could improve the design of future underground urban spaces—as well as one day using her virtual soundscape to enable visitors to experience the sounds of the city themselves.

MIT’s latest ping-pong robot

Robots playing ping-pong have been a thing since the 1980s, of particular interest to scientists because it requires the robot to combine the slow, precise ability to grasp and pick up objects with dynamic, adaptable locomotion. Such robots need high-speed machine vision, fast motors and actuators, precise control, and the ability to make accurate predictions in real time, not to mention being able to develop a game strategy. More recent designs use AI techniques to allow the robots to “learn” from prior data to improve their performance.

MIT researchers have built their own version of a ping-pong playing robot, incorporating a lightweight design and the ability to precisely return shots. They built on prior work developing the Humanoid, a small bipedal two-armed robot—specifically, modifying the Humanoid’s arm by adding an extra degree of freedom to the wrist so the robot could control a ping-pong paddle. They tested their robot by mounting it on a ping-pong table and lobbing 150 balls at it from the other side of the table, capturing the action with high-speed cameras.

The new bot can execute three different swing types (loop, drive, and chip) and during the trial runs it returned the ball with impressive accuracy across all three types: 88.4 percent, 89.2 percent, and 87.5 percent, respectively. Subsequent tweaks to theirrystem brought the robot’s strike speed up to 19 meters per second (about 42 MPH), close to the 12 to 25 meters per second of advanced human players. The addition of control algorithms gave the robot the ability to aim. The robot still has limited mobility and reach because it has to be fixed to the ping-pong table but the MIT researchers plan to rig it to a gantry or wheeled platform in the future to address that shortcoming.

Why orange cats are orange

an orange tabby kitten

Cat lovers know orange cats are special for more than their unique coloring, but that’s the quality that has intrigued scientists for almost a century. Sure, lots of animals have orange, ginger, or yellow hues, like tigers, orangutans, and golden retrievers. But in domestic cats that color is specifically linked to sex. Almost all orange cats are male. Scientists have now identified the genetic mutation responsible and it appears to be unique to cats, according to a paper published in the journal Current Biology.

Prior work had narrowed down the region on the X chromosome most likely to contain the relevant mutation. The scientists knew that females usually have just one copy of the mutation and in that case have tortoiseshell (partially orange) coloring, although in rare cases, a female cat will be orange if both X chromosomes have the mutation. Over the last five to ten years, there has been an explosion in genome resources (including complete sequenced genomes) for cats which greatly aided the team’s research, along with taking additional DNA samples from cats at spay and neuter clinics.

From an initial pool of 51 candidate variants, the scientists narrowed it down to three genes, only one of which was likely to play any role in gene regulation: Arhgap36. It wasn’t known to play any role in pigment cells in humans, mice, or non-orange cats. But orange cats are special; their mutation (sex-linked orange) turns on Arhgap36 expression in pigment cells (and only pigment cells), thereby interfering with the molecular pathway that controls coat color in other orange-shaded mammals. The scientists suggest that this is an example of how genes can acquire new functions, thereby enabling species to better adapt and evolve.

DOI: Current Biology, 2025. 10.1016/j.cub.2025.03.075  (About DOIs).

Not a Roman “massacre” after all

Two of the skeletons excavated by Mortimer Wheeler in the 1930s, dating from the 1st century AD.

Credit: Martin Smith

In 1936, archaeologists excavating the Iron Age hill fort Maiden Castle in the UK unearthed dozens of human skeletons, all showing signs of lethal injuries to the head and upper body—likely inflicted with weaponry. At the time, this was interpreted as evidence of a pitched battle between the Britons of the local Durotriges tribe and invading Romans. The Romans slaughtered the native inhabitants, thereby bringing a sudden violent end to the Iron Age. At least that’s the popular narrative that has prevailed ever since in countless popular articles, books, and documentaries.

But a paper published in the Oxford Journal of Archaeology calls that narrative into question. Archaeologists at Bournemouth University have re-analyzed those burials, incorporating radiocarbon dating into their efforts. They concluded that those individuals didn’t die in a single brutal battle. Rather, it was Britons killing other Britons over multiple generations between the first century BCE and the first century CE—most likely in periodic localized outbursts of violence in the lead-up to the Roman conquest of Britain. It’s possible there are still many human remains waiting to be discovered at the site, which could shed further light on what happened at Maiden Castle.

DOI: Oxford Journal of Archaeology, 2025. 10.1111/ojoa.12324  (About DOIs).

Photo of Jennifer Ouellette

Jennifer is a senior writer at Ars Technica with a particular focus on where science meets culture, covering everything from physics and related interdisciplinary topics to her favorite films and TV series. Jennifer lives in Baltimore with her spouse, physicist Sean M. Carroll, and their two cats, Ariel and Caliban.

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a-2,000-year-old-battle-ended-in-fire,-and-a-tree-species-never-recovered

A 2,000-year-old battle ended in fire, and a tree species never recovered

Then everything changed when the Fire Nation—sorry, the Han Empire—attacked.

Han rose to power in the wake of Qin’s collapse, after a short war with a rival dynasty called Chu, and spent the next century smugly referring to Nanyue as a vassal state and occasionally demanding tribute. At times, the rulers of Nanyue played along, but it all came to a head around 111 BCE, in the wake of an attempted coup and a series of assassinations. The Han Emperor sent an army of between 100,000 and 200,000 soldiers to invade Nanyue under a general named Lu Bode.

The troops marched across the countryside from five directions, converging outside Nanyue’s capital city of Panyou, which stood in the Pearl River Delta, near the modern city of Guangzhou. An enterprising company commander named Yang Pu got the bright idea to set the city on fire, and it ended badly.

“The fire not only destroyed the city but also ran out of control to the surrounding forests,” write Wang and colleagues. The cypress trees burned down to the waterline, leaving only their submerged stumps behind.

map of a coastal area showing elevation and the location of ancient forests

The brown dots mark the known sites of buried forests, and the orange diamonds mark those confirmed to be ancient. The two yellow diamonds are Wang and colleagues’ study sites. Credit: Wang et al. 2025

After war came fire and rice

At the time of the invasion, the land around Panyou was mostly swamp, forested with cypress trees. People had lived there for thousands of years, and had been growing rice for about 2,000 years. Bits of charcoal in the peat layers Wang and colleagues sampled reveal that they practiced slash-and-burn agriculture, but on a small scale, rotating their fields so the cypress forest could start to recover after a season or two.

The small burns are nothing like the forest fire Yang Pu unleashed, or the massive burning and reworking of the landscape that came after.

The stumps of the burned cypress trees slowly disappeared under several meters of peat, while above the buried ancient forest, life went on. Tigers, elephants, rhinos, and green peafowl no longer walked here. Instead, grains of pollen from the layers of clay above the peat reveal a sudden influx of plants from the grassy Poaceae family, which includes rice, wheat, and barley.

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painted-altar-in-maya-city-of-tikal-reveals-aftermath-of-ancient-coup

Painted altar in Maya city of Tikal reveals aftermath of ancient coup


It’s always about colonialism

The altar marks the presence of an enclave of foreign elites from Teotihuacan.

This rendering shows what the altar might have looked like in its heyday. Credit: Heather Hurst

A family altar in the Maya city of Tikal offers a glimpse into events in an enclave of the city’s foreign overlords in the wake of a local coup.

Archaeologists recently unearthed the altar in a quarter of the Maya city of Tikal that had lain buried under dirt and rubble for about the last 1,500 years. The altar—and the wealthy household behind the courtyard it once adorned—stands just a few blocks from the center of Tikal, one of the most powerful cities of Maya civilization. But the altar and the courtyard around it aren’t even remotely Maya-looking; their architecture and decoration look like they belong 1,000 kilometers to the west in the city of Teotihuacan, in central Mexico.

The altar reveals the presence of powerful rulers from Teotihuacan who were there at a time when a coup ousted Tikal’s Maya rulers and replaced them with a Teotihuacan puppet government. It also reveals how hard those foreign rulers fell from favor when Teotihuacan’s power finally waned centuries later.

image of a rectangular limestone structure with recessed panels underground

Archaeologists don’t know what’s inside the altar, because they can’t excavate it without damaging the fragile painted panels. Credit: Ramirez et al. 2025

The painted altar

The altar stands in the courtyard of what was once a wealthy, influential person’s home in Tikal. At just over 1 meter tall, spanning nearly 2 meters in length and 1.3 meters wide, the altar is clearly the centerpiece of the limestone patio space.

It’s made of carved stone and earthen layers, covered with several smooth, fine plaster coatings. Murals adorn recessed panels on all four sides. In red, orange, yellow, and black, the paintings all depict the face of a person in an elaborate feathered headdress, but each is slightly different. All four versions of the face stare straight at the viewer through almond-shaped eyes. The figure wears the kind of facial piercings that would have marked a person of very high rank in Teotihuacan: a nose bar and spool-shaped ear jewelry (picture a fancy ancient version of modern earlobe plugs).

Proyecto Arqueológico del Sur de Tikal archaeologist Edwin Ramirez and his colleagues say the faces on the altar look uncannily like a deity who often shows up in artwork from central Mexico, in the area around Teotihuacan. Archaeologists have nicknamed this deity the Storm God, since they haven’t yet found any trace of its name. It’s a distinctly Teotihuacan-style piece of art, from the architecture of the altar to the style and color of the images and even the techniques used in painting them. Yet it sits in the heart of Tikal, a Maya city.

A pre-Columbian coup d’etat

Tikal was one of the biggest and most important cities of the Maya civilization. Founded in 850 BCE, it chugged along for centuries as a small backwater until its sudden rise to wealth and prominence around 100 CE. Lidar surveys of Guatemala have revealed Tikal’s links with other Maya cities, like Homul. And Tikal also traded with the city of Teotihuacan, more than 1,000 kilometers to the west, in what’s now Mexico.

“These powers of central Mexico reached into the Maya world because they saw it as a place of extraordinary wealth, of special feathers from tropical birds, jade, and chocolate,” says Brown University archaeologist Stephen Houston, a co-author of the recent study, in a statement. “As far as Teotihuacan was concerned, it was the land of milk and honey.”

Trade with Teotihuacan brought wealth to Tikal, but the Maya city seems to have attracted too much attention from its more powerful neighbor. A carved stone unearthed in Tikal in the 1960s describes how Teotihuacan swooped in around 378 CE to oust Tikal’s king and replace him with a puppet ruler. Spanish-language sources call this coup d’etat the Entrada.

The stone is carved in the style of Teotihuacan, but it’s also covered with Maya hieroglyphs, which tell the tale of the conquest. After the Entrada, there are traces of Teotihuacan’s presence all over Tikal, from royal burials in a necropolis to distinctly Mexican architecture mixed with Maya elements in a complex of residential and ceremonial buildings near the heart of the city.

And the newly unearthed altar seems to have been built shortly after the Entrada, based on radiocarbon dates from nearby graves in the courtyard and from material used to ritually bury the altar after its abandonment (more on that below).

Ramirez and his colleagues write that the altar is “likely evidence of the direct presence of Teotihuacan at Tikal as part of a foreign enclave that coincided with the historic Entrada.”

orthographic map of Tikal

This map shows the courtyard in relation to other major structures in Tikal. Credit: T.G. Garrison and H. Hurst

A wealthy household’s ritual courtyard

The buildings surrounding the courtyard would have been a residential compound for wealthy elites in the city; it’s not far from the city’s center with its temples and huge public plazas. Residents had used the courtyard as a private family ceremonial space for decades or even a couple of centuries before its owners installed the altar. And Ramirez and his colleagues say it’s no coincidence that archaeologists have found many such courtyards in Teotihuacan, which people also used as a space for household ceremonies like burials and offerings to the gods.

“What the altar confirms is that wealthy leaders from Teotihuacan came to Tikal and created replicas of ritual facilities that would have existed in their home city. It shows Teotihuacan left a heavy imprint there,” says Houston.

And in the Maya world, as in the world of Teotihuacan, ceremonial spaces usually come with skeletons included.

Ramirez and his colleagues unearthed the grave of an adult buried beneath the patio, in a tomb with limestone walls and a stucco floor. Nearby, a child had been buried in a seated position—something rare in Tikal but very common in Teotihuacan. The child’s burial radiocarbon-dated to decades before the Entrada, between 205 and 350 CE. It looks like someone buried both of these people beneath the floor of the courtyard of their residential compound not long after they moved in; it’s a good bet that they were members of the family who once lived here, but archaeologists don’t know for sure. These kinds of burials would have been exactly the sort of household ritual the courtyard was meant for.

Teotihuacan’s enclave in Maya Tikal

Sometime later—between 380 and 540 CE, based on radiocarbon dating—the people living in the compound buried the courtyard beneath a layer of dirt and rubble, laid a new floor over it, and essentially started over. This is when Ramirez and his colleagues say someone built and painted the altar.

It’s also when someone buried three babies in the courtyard, each near a corner of the altar (the fourth corner has a jar that probably once contained an offering, but no bones). Each burial required breaking the stone floor, placing the tiny remains underneath, and then filling in the hole with crushed limestone. That’s not the way most people in Tikal would have buried an infant, but it’s exactly how archaeologists have found several buried in very similar courtyards in faraway Teotihuacan.

In other words, the people who lived in this compound and used this courtyard and painted altar were probably from Teotihuacan or raised in a Teotihuacan enclave in the southern sector of Tikal. The compound is practically in the shadow of a replica of Teotihuacan’s Feathered Serpent Pyramid and its walled plaza, where archaeologists unearthed Teotihuacan-style incense burners made from local materials.

sketch of a rectangular altar with painted sides

This rendering shows what the altar might have looked like in its heyday. Credit: Heather Hurst

The end of an era

Sometime between 550 CE and 654 CE, based on radiocarbon dating, the foreign enclave in Tikal closed up shop. That’s around the time distant Teotihuacan’s power was starting to collapse. But it wasn’t enough to just leave; important buildings had to be ritually “killed” and buried. That meant burning the area around the altar, but it also meant that people buried the altar, the courtyard, the compound, and most of southern Tikal’s Teotihuacan enclave beneath several meters of dirt and rubble.

Whoever did the burying went to the trouble of making the whole thing look like a natural hill. Ramirez and his colleagues say that’s unusual, because typically once a building had been ritually killed and abandoned, something new would be built atop the remains.

“The Maya regularly buried buildings and rebuilt on top of them,” Brown University archaeologist Andrew Scherer, a co-author of the recent study, said in a statement. “But here, they buried the altar and surrounding buildings and just left them, even though this would have been prime real estate centuries later. They treated it almost like a memorial or a radioactive zone. It probably spoke to the complicated feelings they had about Teotihuacan.”

Antiquity, 2017. DOI: 10.15184/aqy.2025.3 (About DOIs).

Photo of Kiona N. Smith

Kiona is a freelance science journalist and resident archaeology nerd at Ars Technica.

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research-roundup:-7-cool-science-stories-we-almost-missed

Research Roundup: 7 cool science stories we almost missed


Peruvian mummy tattoos, the wobbly physics of spears and darts, quantum “cat states,” and more.

Lasers revealed tattoos on the hand of a 1200-year-old Peruvian mummy. Credit: Michael Pittman and Thomas G Kaye

It’s a regrettable reality that there is never time to cover all the interesting scientific stories each month. In the past, we’ve featured year-end roundups of cool science stories we missed. This year, we’re experimenting with a monthly collection. January’s list includes papers on using lasers to reveal Peruvian mummy tattoos; the physics of wobbly spears and darts; how a black hole changes over time; and quantum “cat states” for error correction in quantum computers, among other fascinating research.

Tracking changes in a black hole over time

Left: EHT images of M87from the 2018 and 2017 observation campaigns. Middle: Example images from a general relativistic magnetohydrodynamic (GRMHD) simulation at two different times. Right: Same simulation snapshots, blurred to match the EHT’s observational resolution. Credit: EHT collaboration

In 2019, the Event Horizon Telescope announced the first direct image ever taken of a black hole at the center of an elliptical galaxy, Messier 87 (M87), located in the constellation of Virgo some 55 million light-years away. Astronomers have now combined earlier observational data to learn more about the turbulent dynamics of plasma near M87*’s event horizon over time, according to a paper published in the journal Astronomy and Astrophysics.

Co-author Luciano Rezzolla of Goethe University Frankfurt in Germany likened the new analysis to comparing two photographs of Mount Everest, one year apart. While the mountain’s basic structure is unlikely to change much in that time, one could observe changes in clouds near the peak and deduce from that properties like wind direction. For instance, in the case of M87*, the new analysis confirmed the presence of a luminous ring that is brightest at the bottom, which in turn confirmed that the rotational axis points away from Earth. “More of these observations will be made in the coming years and with increasing precision, with the ultimate goal of producing a movie of what happens near M87*,” said Rezolla.

Astronomy and Astrophysics, 2025. DOI: 10.1051/0004-6361/202451296 (About DOIs).

Lasers reveal Peruvian mummy tattoos

A tattooed forearm of a Chancay mummy

A tattooed forearm of a Chancay mummy. Credit: Michael Pittman and Thomas G Kaye

Humans across the globe have been getting tattoos for more than 5,000 years, judging by traces found on mummified remains from Europe to Asia and South America. But it can be challenging to decipher details of those tattoos, given how much the ink tends to “bleed” over time, along with the usual bodily decay. Infrared imaging can help, but in an innovative twist, scientists decided to use lasers that make skin glow ever so faintly, revealing many fine hidden details of tattoos found on 1,200-year-old Peruvian mummies, according to a paper published in the Proceedings of the National Academy of Sciences.

It’s the first time the laser-stimulated fluorescence (LSF) technique has been used on mummified human remains. The skin’s fluorescence essentially backlights any tattoos, and after post-processing, the long-exposure photographs showed white skin behind black outlines of the tattoo art—images so detailed it’s possible to measure density differences in the ink and eliminate any bleed effects. The authors determined that the tattoos on four mummies—geometric patterns with triangles and diamonds—were made with carbon-based black ink skillfully applied with a pointed object finer than a standard modern tattoo needle, possibly a cactus needle or sharpened bone.

PNAS, 2025. DOI: 10.1073/pnas.2421517122 (About DOIs).

Sforza Castle’s hidden passages

Ground-penetrating radar reveals new secrets under Milan's Sforza Castle

Ground-penetrating radar reveals new secrets under Milan’s Sforza Castle Credit: Politecnico di Milano

Among the many glories of Milan is the 15th-century Sforza Castle, built by Francesco Sforza on the remnants of an earlier fortification as his primary residence. Legends about the castle abound, most notably the existence of secret underground chambers and passages. For instance, Ludovico il Moro, Duke of Milan from 1494–1499, was so heartbroken over the loss of his wife in childbirth that he used an underground passageway to visit her tomb in the Basilica of Santa Maria delle Grazie—a passageway that appears in the drawings of Leonardo da Vinci, who was employed at the court for a time.

Those underground cavities and passages are now confirmed, thanks to a geophysical survey using ground-penetrating radar and laser scanning, performed as part of a PhD thesis. Various underground cavities and buried passageways were found within the castle’s outer walls, including Ludovico’s passageway and what have may have been secret military passages. Those involved in the project plan to create a “digital twin” of Sforza Castle based on the data collected, one that incorporates both its current appearance and its past. Perhaps it will also be possible to integrate that data with augmented reality to provide an immersive digital experience.

Physics of wobbly spears and darts

Image sequence of a 100-mm long projectile during a typical ejection in experiments.

Image sequence of a 100-mm-long projectile during a typical ejection in experiments. Credit: G. Giombini et al., 2025

Among the things that make humans unique among primates is our ability to throw various objects with speed and precision (with some practice)—spears or darts, for example. That’s because the human shoulder is anatomically conducive to storing and releasing the necessary elastic energy, a quality that has been mimicked in robotics to improve motor efficiency. According to the authors of a paper published in the journal Physical Review E, the use of soft elastic projectiles can improve the efficiency of throws, particularly those whose tips are weighted with a mass like a spearhead.

Guillaume Giombini of the Université Côte d’Azur in Nice, France, and co-authors wanted to explore this “superpropulsion” effect more deeply, using a combination of experimental data, numerical simulation, and theoretical analysis. The projectiles they used in their experiments were inspired by archery bows and consisted of two flat steel cantilevers connected by a string, essentially serving as springs to give the projectile the necessary elasticity. They placed a flat piece of rigid plastic in the middle of the string as a platform. Some of the projectiles were tested alone, while others were weighted with end masses. A fork held each projectile in place before launch, and the scientists measured speed and deformation during flight. They found that the wobble produced by the weighted tip projectiles yielded a kinetic energy gain of 160 percent over more rigid, unweighted projectiles.

Physical Review E, 2025. DOI: 10.1103/PhysRevE.00.005500  (About DOIs).

Quantum “cat states” for error detection

Left to right: UNSW researchers Benjamin Wilhelm, Xi Yu, Andrea Morello, and Danielle Holmes, all seated and each holding a cat on their lap

Left to right: UNSW researchers Benjamin Wilhelm, Xi Yu, Andrea Morello, and Danielle Holmes. Credit: UNSW Sydney/CC BY-NC

The Schrödinger’s cat paradox in physics is an excellent metaphor for the superposition of quantum states in atoms. Over the last 20 years, physicists have managed to build various versions of Schrödinger’s cat in the laboratory whereby two or more particles manage to be in two different states at the same time—so-called “cat states,” such as six atoms in simultaneous “spin up” and “spin down” states, rather like spinning clockwise and counterclockwise at the same time. Such states are fragile, however, and quickly decohere. Physicists at the University of New South Wales came up with a fresh twist on a cat-state that is more robust, according to a paper published in the journal Nature Physics.

They used an antimony atom embedded within a silicon quantum chip. The atom is quite heavy and has a large nuclear spin that can go in eight directions rather than just two (spin up and spin down). This could help enormously with quantum error correction, one of the biggest obstacles in quantum computing, because there is more room for error in the binary code. “As the proverb goes, a cat has nine lives,” said co-author Xi Yu of UNSW. “One little scratch is not enough to kill it. Our metaphorical ‘cat’ has seven lives: it would take seven consecutive errors to turn the ‘0’ into a ‘1.’” And embedding the atom in a silicon chip makes it scalable.

Nature Physics, 2025. DOI: 10.1038/s41567-024-02745-0  (About DOIs).

New twist on chain mail armor

how polycatenated architected materials look in their fluid or granular state, conforming to the shape of the vessel in which it is held.

Credit: Wenjie Zhou

Scientists have developed a new material that is like “chain mail on steroids,” capable of responding as both a fluid or a solid, depending on the kind of stress applied, according to a paper published in the journal Science. That makes it ideal for manufacturing helmets or other protective gear, as well as biomedical devices and robotics components. The technical term is polycatenated architected materials (PAMs). Much like how chain mail is built from small metal rings linked together into a mesh, PAMs are composed of various interlocking shapes that can form a wide range of different 3D patterns.

The authors were partly inspired by the lattice structure of crystals; they just replaced fixed particles with rings or cage-like shapes made out of different materials—such as acrylic polymers, nylon, or metals—to make small 3D-printed structures small enough to fit in the palm of one’s hand. They then subjected these materials to various stressors in the laboratory: compression, a lateral shearing force, and twisting. Some of the materials felt like hard solids, others were squishier, but they all exhibited the same kind of telltale transition, behaving more like a fluid or a solid depending on the stressor applied. PAMs at the microscale can also expand or contract in response to electrical charges. This makes them a useful hybrid material, spanning the gap between granular materials and elastic deformable ones.

W. Zhou et al., Science, 2025. DOI: 10.1126/science.adr9713  (About DOIs).

Kitty robot mimics headbutts

Any cat lover will tell you that cats show humans affection by rubbing their heads against the body (usually shins or hands). It’s called “bunting,” often accompanied by purring, and it’s one of the factors that make companion animal therapy so effective, per the authors of a paper published in ACM Transactions on Human-Robot Interactions. That’s why they built a small robot designed to mimic bunting behavior, conducting various experiments to assess whether human participants found their interactions with the kitty-bot therapeutic. The robot prototypes were small enough to fit on a human lap, featuring a 3D-printed frame and a head covered with furry polyester fabric.

The neck needed to be flexible to mimic the bunting behavior, so the authors incorporated a mechanism that could adjust the stiffness of the neck via wire tension. They then tested various prototypes with university students, setting the neck stiffness to low, high, and variable. The students said they felt less tense after interacting with the robots. There was no significant difference between the settings, although participants slightly preferred the variable setting. We know what you’re thinking: Why not just get an actual cat or visit your local cat cafe? The authors note that many people are allergic to cats, and there is also a risk of bites, scratches, or disease transmission—hence the interest in developing animal-like robots for therapeutic applications.

ACM Transactions on Human-Robot Interactions, 2025. DOI: 10.1145/3700600  (About DOIs).

Photo of Jennifer Ouellette

Jennifer is a senior writer at Ars Technica with a particular focus on where science meets culture, covering everything from physics and related interdisciplinary topics to her favorite films and TV series. Jennifer lives in Baltimore with her spouse, physicist Sean M. Carroll, and their two cats, Ariel and Caliban.

Research Roundup: 7 cool science stories we almost missed Read More »

a-telltale-toilet-reveals-“lost”-site-shown-in-bayeux-tapestry

A telltale toilet reveals “lost” site shown in Bayeux Tapestry

Seats of power

The Bayeux Tapestry, showing King Harold riding to Bosham, where he attends church and feasts in a hall, before departing for France. The Society of Antiquaries of London

According to Creighton and his co-authors, there has been quite a lot of research on castles, which dominated aristocratic sites in England after the Norman Conquest. That event “persists as a deep schism that continues to be seen as the watershed moment after which elites finally tapped into the European mainstream of castle construction,” they wrote. The study of residences (or “lordly enclaves”) has been more peripheral, yet the authors argue that up until 1066, aristocrats and rulers like King Harold invested heavily in residences, often co-located with churches and chapels.

The “Where Power Lies” project employed a wide range of research methodology—including perusing old maps and records, a re-analysis of past excavations, geophysics, ground-penetrating radar (GPR), and photogrammatic modeling—to define the signatures of such enclaves and map them into a single geographic information database (GIS). The project has identified seven such “lordly centers,” two of which are discussed in the current paper: an early medieval enclosure at Hornby in North Yorkshire and Bosham in West Sussex.

It has long been suspected that one particular manor house in Bosham (now a private residence) stands on the site of what was once King Harold’s residence. Per the authors, the original residence was clearly connected with Holy Trinity Church just to the south, parts of which date back to the 11th century, as evidenced by the posthole remains of what was once a bridge or causeway. More evidence can be found in a structure known as the “garden ruin,” little of which survives above ground—and even that was heavily overgrown. GPR data showed buried features that would have been the eastern wall of King Harold’s lordly enclave.

The biggest clue was the discovery in 2006 of a latrine within the remains of a large timber building. Its significance was not recognized at the time, but archaeologists have since determined that high-status homes began integrating latrines in the 10th century, so the structure was most likely part of King Harold’s residence. Co-author Duncan Wright of Newcastle University believes this “Anglo-Saxon en suite,” along with all the other evidence, proves “beyond all reasonable doubt that we have here the location of Harold Godwinson’s private power center, the one famously depicted on the Bayeux Tapestry.”

DOI: The Antiquaries Journal, 2025. 10.1017/S0003581524000350  (About DOIs).

A telltale toilet reveals “lost” site shown in Bayeux Tapestry Read More »

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Skull long thought to be Cleopatra’s sister’s was actually a young boy

Scientists have demonstrated that an ancient human skull excavated from a tomb at Ephesos was not that of Arsinoë IV, half-sister to Cleopatra VII. Rather, it’s the skull of a young male between the ages of 11 and 14 from Italy or Sardinia, who may have suffered from one or more developmental disorders, according to a new paper published in the journal Scientific Reports. Arsinoë IV’s remains are thus still missing.

Arsinoë IV led quite an adventurous short life. She was either the third or fourth daughter of Ptolemy XII, who left the throne to Cleopatra and his son, Ptolemy XIII, to rule together. Ptolemy XIII didn’t care for this decision and dethroned Cleopatra in a civil war—until Julius Caesar intervened to enforce their father’s original plan of co-rulership. As for Arsinoë, Caesar returned Cyprus to Egyptian rule and named her and her youngest brother (Ptolemy XIV) co-rulers. This time, it was Arsinoë who rebelled, taking command of the Egyptian army and declaring herself queen.

She was fairly successful at first in battling the Romans, conducting a siege against Alexandria and Cleopatra, until her disillusioned officers decided they’d had enough and secretly negotiated with Caesar to turn her over to him. Caesar agreed, and after a bit of public humiliation, he granted Arsinoë sanctuary in the temple of Artemis in Ephesus. She lived in relative peace for a few years, until Cleopatra and Mark Antony ordered her execution on the steps of the temple—a scandalous violation of the temple as a place of sanctuary. Historians disagree about Arsinoë’s age when she died: Estimates range from 22 to 27.

Archaeologists have been excavating the ancient city of Ephesus for more than a century. The Octagon was uncovered in 1904, and the burial chamber was opened in 1929. That’s where Joseph Keil found a skeleton in a sarcophagus filled with water, but for some reason, Keil only removed the cranium from the tomb before sealing it back up. He took the skull with him to Germany and declared it belonged to a likely female around 20 years old, although he provided no hard data to support that conclusion.

It was Hilke Thur of the Austrian Academy of Sciences who first speculated that the skull may have belonged to Arsinoë IV, despite the lack of an inscription (or even any grave goods) on the tomb where it was found. Old notes and photographs, as well as craniometry, served as the only evidence. The skull accompanied Keil to his new position at the University of Vienna, and there was one 1953 paper reporting on craniometric measurements, but after that, the skull languished in relative obscurity. Archaeologists at the University of Graz rediscovered the skull in Vienna in 2022. The rest of the skeleton remained buried until the chamber was reopened and explored further in the 1980s and 1990s, but it was no longer in the sarcophagus.

Skull long thought to be Cleopatra’s sister’s was actually a young boy Read More »

studies-pin-down-exactly-when-humans-and-neanderthals-swapped-dna

Studies pin down exactly when humans and Neanderthals swapped DNA


We may owe our tiny sliver of Neanderthal DNA to just a couple of hundred Neanderthals.

The artist’s illustration shows what the six people buried at the Ranis site, who lived between 49, 500 and 41,000 years ago, may have looked like. Two of these people are mother and daughter, and the mother is a distant cousin (or perhaps a great-great-grandparent or great-great-grandchild) to a woman whose skull was found 130 kilometers away in what’s now Czechia. Credit: Sumer et al. 2024

Two recent studies suggest that the gene flow (as the young people call it these days) between Neanderthals and our species happened during a short period sometime between 50,000 and 43,500 years ago. The studies, which share several co-authors, suggest that our torrid history with Neanderthals may have been shorter than we thought.

Pinpointing exactly when Neanderthals met H. sapiens  

Max Planck Institute of Evolutionary Anthropology scientist Leonardo Iasi and his colleagues examined the genomes of 59 people who lived in Europe between 45,000 and 2,200 years ago, plus those of 275 modern people whose ancestors hailed from all over the world. The researchers cataloged the segments of Neanderthal DNA in each person’s genome, then compared them to see where those segments appeared and how that changed over time and distance. This revealed how Neanderthal ancestry got passed around as people spread around the world and provided an estimate of when it all started.

“We tried to compare where in the genomes these [Neanderthal segments] occur and if the positions are shared among individuals or if there are many unique segments that you find [in people from different places],” said University of California Berkeley geneticist Priya Moorjani in a recent press conference. “We find the majority of the segments are shared, and that would be consistent with the fact that there was a single gene flow event.”

That event wasn’t quite a one-night stand; in this case, a “gene flow event” is a period of centuries or millennia when Neanderthals and Homo sapiens must have been in close contact (obviously very close, in some cases). Iasi and his colleagues’ results suggest that happened between 50,500 and 43,000 years ago. But it’s quite different from our history with another closely related hominin species, the now-extinct Denisovans, with whom different Homo sapiens groups met and mingled at least twice on our way to taking over the world.

In a second study, Arev Sümer (also of the Max Planck Institute) and her colleagues found something very similar in the genomes of people who lived 49,500 to 41,000 years ago in what’s now the area around Ranis, Germany. The Ranis population, based on how their genomes compare to other ancient and modern people, seem to have been part of one of the first groups to split off from the wave of humans who migrated out of Africa, through the Levant, and into Eurasia sometime around 50,000 years ago. They carried with them traces of what their ancestors had gotten up to during that journey: about 2.9 percent of their genomes were made up of segments of Neanderthal ancestry.

Based on how long the Ranis people’s segments of Neanderthal DNA were (longer chunks of Neanderthal ancestry tend to point to more recent mixing), the interspecies mingling happened about 80 generations, or about 2,300 years, before the Ranis people lived and died. That’s about 49,000 to 45,000 years ago. The dates from both studies line up well with each other and with archaeological evidence that points to when Neanderthal and Homo sapiens cultures overlapped in parts of Europe and Asia.

What’s still not clear is whether that period of contact lasted the full 5,000 to 7,000 years, or if, as Johannes Krause (also of the Max Planck Institute) suggests, it was only a few centuries—1,500 years at the most—that fell somewhere within that range of dates.

Artist’s depiction of a Neanderthal.

Natural selection worked fast on our borrowed Neanderthal DNA

Once those first Homo sapiens in Eurasia had acquired their souvenir Neanderthal genes (forget stealing a partner’s hoodie; just take some useful segments of their genome), natural selection got to work on them very quickly, discarding some and passing along others, so that by about 100 generations after the “event,” the pattern of Neanderthal DNA segments in people’s genomes looked a lot like it does today.

Iasi and his colleagues looked through their catalog of genomes for sections that contained more (or less) Neanderthal ancestry than you’d expect to find by random chance—a pattern that suggests that natural selection has been at work on those segments. Some of the segments that tended to include more Neanderthal gene variants included areas related to skin pigmentation, the immune response, and metabolism. And that makes perfect sense, according to Iasi.

“Neanderthals had lived in Europe, or outside of Africa, for thousands of years already, so they were probably adapted to their environment, climate, and pathogens,” said Iasi during the press conference. Homo sapiens were facing selective pressure to adapt to the same challenges, so genes that gave them an advantage would have been more likely to get passed along, while unhelpful ones would have been quick to get weeded out.

The most interesting questions remain unanswered

The Neanderthal DNA that many people carry today, the researchers argue, is a legacy from just 100 or 200 Neanderthals.

“The effective population size of modern humans outside Africa was about 5,000,” said Krause in the press conference. “And we have a ratio of about 50 to 1 in terms of admixture [meaning that Neanderthal segments account for about 2 percent of modern genomes in people who aren’t of African ancestry], so we have to say it was about 100 to maybe 200 Neanderthals roughly that mixed into the population.” Assuming Krause is right about that and about how long the two species stayed in contact, a Homo sapiens/Neanderthal pairing would have happened every few years.

So we know that Neanderthals and members of our species lived in close proximity and occasionally produced children for at least several centuries, but no artifacts, bones, or ancient DNA have yet revealed much of what that time, or that relationship, was actually like for either group of people.

The snippets of Neanderthal ancestry left in many modern genomes, and those of people who lived tens of thousands of years ago, don’t offer any hints about whether that handful of Neanderthal ancestors were mostly male or mostly female, which is something that could shed light on the cultural rules around such pairings. And nothing archaeologists have unearthed so far can tell us whether those pairings were consensual, whether they were long-term relationships or hasty flings, or whether they involved social relationships recognized by one (or both) groups. We may never have answers to those questions.

And where did it all happen? Archaeologists haven’t yet found a cave wall inscribed with “Og heart Grag,” but based on the timing, Neanderthals and Homo sapiens probably met and lived alongside each other for at least a few centuries, somewhere in “the Near East,” which includes parts of North Africa, the Levant, what’s now Turkey, and what was once Mesopotamia. That’s one of the key routes that people would have followed as they migrated from Africa into Europe and Asia, and the timing lines up with when we know that both Homo sapiens and Neanderthals were in the area.

“This [same] genetic admixture also appears in East Asia and Australia and the Americas and Europe,” said Krause. “If it would have happened in Europe or somewhere else, then the distribution would probably look different than what we see.”

Science, 2023 DOI: 10.1126/science.adq3010;

Nature, 2023 DOI: 10.1038/s41586-024-08420-x;

(About DOIs).

Photo of Kiona N. Smith

Kiona is a freelance science journalist and resident archaeology nerd at Ars Technica.

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paleolithic-deep-cave-compound-likely-used-for-rituals

Paleolithic deep-cave compound likely used for rituals

Archaeologists excavating a paleolithic cave site in Galilee, Israel, have found evidence that a deep-cave compound at the site may have been used for ritualistic gatherings, according to a new paper published in the Proceedings of the National Academy of Sciences (PNAS). That evidence includes the presence of a symbolically carved boulder in a prominent placement, and well as the remains of what may have been torches used to light the interior. And the acoustics would have been conducive to communal gatherings.

Dating back to the Early Upper Paleolithic period, Manot Cave was found accidentally when a bulldozer broke open its roof during construction in 2008. Archaeologists soon swooped in and recovered such artifacts as stone tools, bits of charcoal, remains of various animals, and a nearly complete human skull.

The latter proved to be especially significant, as subsequent analysis showed that the skull (dubbed Manot 1) had both Neanderthal and modern features and was estimated to be about 54,700 years old. That lent support to the hypothesis that modern humans co-existed and possibly interbred with Neanderthals during a crucial transition period in the region, further bolstered by genome sequencing.

The Manot Cave features an 80-meter-long hall connecting to two lower chambers from the north and south. The living section is near the entrance and was a hub for activities like flint-knapping, butchering animals, eating, and other aspects of daily life. But about eight stories below, there is a large cavern consisting of a high gallery and an adjoining smaller “hidden” chamber separated from the main area by a cluster of mineral deposits called speleothems.

That’s the area that is the subject of the new PNAS paper. Unlike the main living section, the authors found no evidence of daily human activities in this compound, suggesting it served another purpose—most likely ritual gatherings.

Paleolithic deep-cave compound likely used for rituals Read More »

dog-domestication-happened-many-times,-but-most-didn’t-pan-out

Dog domestication happened many times, but most didn’t pan out

The story that data reveals is complicated—but somehow very human.

Until about 13,600 years ago, any wolf living in what is now Alaska would have lived on the usual wolf diet: rabbits, moose, and a whole range of other land animals. But starting around 13,600 years ago, the nitrogen isotopes locked in ancient wolves’ bones suggest that something changed. Some wolves still made their living solely by hunting wild game, but others started living almost entirely on fish. Since it’s unlikely that Alaskan wolves had suddenly taken up fly fishing, the sudden change probably suggests that some wolves had started getting food from people.

They’re good dogs, Brent

The fact that we kept trying to befriend wolves is starkly clear at a site called Hollembaek Hill, where archaeologists unearthed the 8,100-year-old remains of four canines. Their diets (according to the nitrogen isotopes locked in their bones) consisted mostly of salmon, so it’s tempting to assume these were domesticated dogs. But their DNA reveals that all four—including a newborn puppy—are most closely related to modern wolves.

On the other hand, the Hollembaek Hill canines didn’t all look like wild wolves. At least one of them had the large stature of a modern wolf, but others were smaller, like early dogs. And some of their DNA suggests that they may be at least part dog but not actually related to modern dogs. Lanoë and his colleagues suggest that people at Hollembaek Hill 8,000 years ago were living alongside a mix of pet wolves (do not try this at home) and wolf-dog hybrids.

All modern dogs trace their roots to a single group of wolves (now extinct) that lived in Siberia around 23,000 years ago. But sometime between 11,300 and 12,800 years ago, the canines from Hollembaek Hill and another Alaskan site called Swan Point had dog DNA that doesn’t seem related to modern dogs at all. That may suggest that dog domestication was a process that happened several times in different places, creating several branches of a dog family tree, but only one stuck around in the long run.

In other words, long after humans “invented” dogs, it seems that people just kept repeating the process, doing the things that created dogs in the first place: allowing the friendliest, least aggressive wild canids to live near their villages and maybe adopting and feeding them.

Dog domestication happened many times, but most didn’t pan out Read More »

ancient-fish-trapping-network-supported-the-rise-of-maya-civilization

Ancient fish-trapping network supported the rise of Maya civilization

Harrison-Buck and her colleagues calculated that at its peak, the system could have produced enough fish each year to feed around 15,000 people. That’s based on modern estimates of how many kilograms of fish people eat every year, combined with measurements of how many kilograms of fish people in Zambia harvest with similar traps. Of course, people at Crooked Tree would have needed to preserve the fish somehow, probably by salting, drying, or smoking them.

“Fisheries were more than capable of supporting year-round sedentarism and the emergence of complex society characteristic of Pre-Columbian Maya civilization in this area,” write Harrison-Buck and her colleagues.

When we think about the Maya economy, we think of canal networks and ditched or terraced fields. In just one patch of what’s now Guatemala, a lidar survey revealed that Maya farmers drained thousands of acres of swampy wetland and built raised fields for maize, crossed by a grid of irrigation canals. To feed the ancient city of Holmul, the Maya turned a swamp into a breadbasket. But at least some of their precursors may have made it big on fish, not grain. The common feature, though, is an absolute lack of any chill whatsoever when it came to re-engineering whole landscapes to produce food.

This Google Earth image shows the area containing the ancient fishery.

Infrastructure built to last and last

From the ground, the channels that funneled fish into nearby ponds are nearly invisible today. But from above, especially during the dry season, they stand in stark contrast to the land around them, because vegetation grows rich and green in the moist soil at the base of the channels, even while everything around it dries up. That made aerial photography the perfect way to map them.

Ancient fish-trapping network supported the rise of Maya civilization Read More »

to-invent-the-wheel,-did-people-first-have-to-invent-the-spindle?

To invent the wheel, did people first have to invent the spindle?

It’s not so much that the spindle whorl was the direct evolutionary ancestor of the wheel, the way wolves were the ancestors of modern dogs. Instead, it was one of the first ways that people got really familiar, in a hands-on way, with the idea that you can attach something round to a stick and use it to turn one kind of motion into another. Pottery wheels, which emerged a bit later, work on the same general principle.

“I don’t jump to saying, ‘Okay, spindle whorls are [cart] wheels,” Yashuv tells Ars. “In many studies of the invention of the wheel, they’re talking about sledges and all sorts of things that are focused on the function of transportation—which is correct. I’m just adding another layer: the foundation of the mechanical principle.”

Once that mechanical principle was firmly embedded in humanity’s collective stash of knowledge, it was a matter of time (a few thousand years) before people looked at animal-drawn sledges, then looked at their pottery wheels and spindles, and put two and two together and got a cart with wheels—or at least, that’s Yashuv’s hypothesis. She and Grosman aren’t the first to suggest something similar; early 20th-century archaeologist Gordon V. Childe suggested that most of the major inventions of the Industrial Revolution were just new applications of much older rotary devices.

on the left, a diagram of two hands using a drop spindle. On the right, a woman in a yellow shirt spins thread with a drop spindle.

Spinner Yonit Kristal tests a replica of a spindle from the 12,000-year-old village. Credit: Yashuv and Grosman 2024

A village of prehistoric innovators?

Exactly how long people have understood (and made use of) the whole circle-on-a-stick concept is still an open question. Nahal Ein-Gev II is the oldest site with evidence of drop spindles that archaeologists have found so far, but Yashuv says the villagers there probably weren’t the first to invent the concept. They just happened to make their spindle whorls out of rocks with holes drilled in them, leaving a clear trace in the archaeological record.

Modern spindle whorls are often made of wood—either a disc or an X-shaped pair of arms. The trouble with wood, especially in small pieces, is that it’s not very likely to survive thousands of years (although that’s not impossible), so wooden spindle whorls from a site as old as Nahal Ein-Gev II are invisible to archaeologists. In some cultures, spinners might even tie a rock (or even a potato—no joke) to the end of their fibers in lieu of a spindle. Those rocks lack the telltale drill holes that let Yashuv and Grosman recognize the stone spindle whorls at Nahal Ein-Gev II, so they’re also invisible to archaeologists; they just look like rocks. Nahal Ein-Gev II is just the oldest place that recognizable spindle whorls happen to have survived.

To invent the wheel, did people first have to invent the spindle? Read More »