Humans

Archaeological excavations near Aldborough, UK, are helping us understand life after Roman occupationR Ferraby & M.J. Millet
When the Roman Empire withdrew from Britain, the result was not chaos and economic collapse. The metals industry in what is now northern England continued and even expanded in the subsequent centuries, according to an archaeological record of pollution from metalworking.
“The argument has been that, with the disappearance of state apparatus and linked state transport systems, the regional economies collapse totally,” says Christopher Loveluck at the University of Nottingham in the UK. But that isn’t what the archaeology revealed. “We’re seeing an increase in metal pollution products.”
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Loveluck is part of a team that has excavated Roman remains from Aldborough in North Yorkshire, England. Under Roman rule, this town was called Isurium Brigantum, where metals like iron and lead were mined and processed.
The team found aerosol pollution from these metalworking operations had become trapped in the silt accumulating in an ancient riverbed at the archaeological site. By digging through the layers of sediment, the team was able to reconstruct how pollution levels varied between 345 and 1779 AD.
“They get this long chronology, so you really can trace the ups and the downs,” says Jane Kershaw at the University of Oxford, who wasn’t involved in the research but who has studied early medieval metal mining.

In the late 300s and early 400s, the Roman Empire lost control of Britain and withdrew. “The government apparatus goes, the tax collection apparatus goes, no new coinage arrives in Britain, and they almost certainly withdraw all of the field army units as well,” Loveluck says. The subsequent centuries have few written records, and certain industries – notably wheel-thrown pottery – went into steep decline. This gave rise to a narrative of “the society of 5th century Britain just collapsing”, says Loveluck.
The riverbed record tells a different story. Lead pollution was low during Roman times, and fell only slightly in the late 300s and early 400s. It then rose steadily until the mid-500s. Likewise, pollution from ironworking rose during the first half of the 500s.
This, argues Loveluck, suggests continuity in the large-scale production of essential commodities.
The rise in metal production may have been due to internal fighting, suggests Kershaw. “It’s a period where the various Anglo-Saxon kingdoms are coalescing,” she says. “There’s a lot of fighting between those different kingdoms.” Many men were buried in graves with swords and knives.

Metal production then declined sharply in the mid-500s, and remained low for several decades. The team suggests this might be due to the Justinianic plague, which cut through the lands around the Mediterranean in 541-549 AD. Ancient DNA evidence from a graveyard in east England shows the plague did reach Britain. However, it is not clear how severe or widespread it was. “We don’t have grave pits full of plague victims, for instance, like we do with later plague events,” says Kershaw.
Anglo-Saxon coins dating from the 10th and 11th centuryAndrew Cowie/Alamy
The apparent resilience of Aldborough metal production in the face of the Roman withdrawal fits with other evidence of economic and political continuity. “Droitwich in Worcestershire [in western England] has an unbroken sequence of salt production from the Roman period to the modern period,” says Loveluck.
The period after the Roman withdrawal has been dubbed the Dark Ages, due to a lack of written records and supposed intellectual decline. However, historians say that is at best an oversimplification.
Some practices did cease, like wheel-thrown pottery and building using stone. But this period also saw the production of spectacular metalwork, often using copper. “If everything was so terrible and dark, how come they’re wearing these amazing brooches and they’ve got colourful bead necklaces,” says Kershaw.

Topics:archaeology More

Acanceh in Mexico is home to many Maya peopleEducation Images/Universal Images Group via Getty Images
In the past, the quantity of zinc and other trace elements in human diets was determined largely by levels in local soils. Now it has been shown that our ancestors evolved to cope with local variations in micronutrient levels as they migrated around the world.
This might have led to some dramatic side effects – it is possible, for example, that the short stature of some peoples around the world is a byproduct of adaptation to low iodine levels. It is also possible that these past adaptations are causing some people today to get too much or too little of specific micronutrients.
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“For most of human evolution, the micronutrient composition of what you’re eating has been dependent on the underlying soil,” says Jasmin Rees at the University of Pennsylvania.
Her team has scanned nearly 900 genomes of people from all around the world to find evidence of adaptation to local levels of 13 trace elements, including iron, manganese and selenium. To do so, the team looked for signs of positive selection in 270 genes linked to uptake of these elements – that is, for gene variants that became more common in specific populations because they provided an advantage.
The strongest evidence was in iodine-linked genes in Maya peoples of Central America. Similar signatures were also found in the Mbuti and Biaka peoples in Central Africa, who have a shorter stature than most people.

In 2009, it was suggested that the Mbuti and Biaka peoples’ short stature could be due to adaptation to low iodine. This is because iodine-linked genes influence thyroid hormone activity, which has an effect on growth. These peoples are also known to be less prone to goitre – enlargement of the thyroid gland due to an iodine-deficient diet – than neighbouring groups.
Because the Maya population is also very short-statured, says Rees, her findings support the idea that adaptation to low iodine affects size. She and her colleagues also point out that the rainforest soils in the Maya region are known to be low in iodine.
“This is very speculative,” she says. “We can’t say exactly what is causing these short statures, but we’re seeing, at the very least, a coincidence where there seems to be selection on iodine-associated genes in these short-statured populations.”
In the Uyghur and Brahui peoples of Central and South Asia, where soil magnesium levels are especially high, there is strong selection affecting two genes related to magnesium uptake. Some of these gene variants have previously been linked to low levels of magnesium in the body, so the team suggests these changes reduce magnesium uptake to prevent toxicity from high levels in the environment.
These are just two examples – the team found signs of positive selection related to at least one micronutrient in just about every population around the world. “We see really widespread signatures of adaptation,” says Rees.

This study is just the beginning, she says. More work is needed to pin down the effects of the many gene variants the team identified. Now that food is traded globally, it could turn out that people with certain variants need more or less of specific micronutrients. Rees compares it to how in countries such as the UK, people with darker skin are advised to take vitamin D all year round rather than just in the winter.
“It would be important to know if individuals from particular populations are likely to be especially in need of particular micronutrient supplements,” says Mark Stoneking at the Max Planck Institute for Evolutionary Anthropology in Germany.
“When it comes to identifying signatures of selection from genomic data, they have done state-of-the-art work,” he says. “But a lot more work needs to be done to verify that these have been truly subject to selection – some of them will inevitably turn out to be false positives.”

Topics:human evolution More

Has an asteroid impact influenced the course of human evolution?Anna Ivanova/Alamy
This is an extract from Our Human Story, our newsletter about the revolution in archaeology. Sign up to receive it in your inbox every month.
I am old enough to remember when the idea an asteroid impact wiped out the dinosaurs was new and exciting. When Luis Alvarez and his colleagues first suggested this in 1980 – the year before I was born – it was a big, dramatic claim. They didn’t even have an impact crater, just a layer of anomalous rock. It took decades, and the realisation in the 1990s that the Chicxulub impact crater in Mexico was the right age and size, to firm up the idea. Even now, palaeontologists are divided on whether the impact was the main cause of the mass extinction, or whether dinosaurs were already in decline before the big rock hit.

Obviously, nothing so earth-shattering happened during the period when humans evolved. The Chicxulub impactor was unusually large and exceptionally deadly.
However, life on Earth is subject to a whole host of other space-related threats. One idea doing the rounds is Earth’s magnetic field did something weird about 42,000 years ago. This supposedly caused a global ecological crisis, including possibly contributing to the extinction of the Neanderthals – paving the way for the global dominance of our species. The idea was first proposed in 2021 in Science, and my colleague Karina Shah wrote a news story about it.
What’s more, many other cosmic phenomena affect our planet. Meteorite impacts smaller than Chicxulub can still do a lot of damage to ecosystems in or near the impact zone. There are also risks from radiation from exploding stars or “supernovae”. These amount to an ongoing barrage of threats for life on our planet, including humans and our extinct relatives.

So: have cosmic phenomena influenced the course of human evolution?
Flip flop
Earth’s magnetic field protects us from intense solar radiation and cosmic raysMilos Kojadinovic/Alamy
Let’s first consider Earth’s magnetic field. The field is generated by the movement of molten metal in the planet’s core, which powers vast electrical currents and thus a magnetic field. It extends far out into space and protects us from intense solar radiation and cosmic rays.
However, the magnetic field is not entirely stable. Every few hundred thousand years, it flips direction: the north magnetic pole switches to the south and vice versa. During these reversals, the field weakens and more radiation reaches the surface.
Less dramatically but more frequently, the field undergoes an “excursion”. During an excursion, the field’s strength dramatically weakens, perhaps for thousands of years, and its direction may change – but not fully reverse – before returning to its original state.
42,000 years ago, the magnetic field underwent a particularly big excursion, dubbed the Laschamps event after the village in France where it was first detected. During the event, the magnetic field was almost entirely reversed. The 2021 study suggested it occurred between 41,560 and 41,050 years ago, and lasted a few hundred years.
In that study, researchers found evidence of changes in atmospheric ozone levels during the period when the magnetic field was weakening. This, they said, should have driven “synchronous global climate shifts that caused major environmental changes, extinction events, and transformations in the archaeological record”.
This year we got an update on that idea. In April, a separate group published a follow-up study in Science. They modelled the field excursion in more detail and found the aurora borealis would have been visible further south, including over Europe and northern Africa. This, they argued, would have exposed hominins to more harmful ultraviolet radiation.
The authors go on to suggest modern humans in western Eurasia may have used red pigments called ochre at this time – perhaps as a sunscreen. Those same people also seem to have had better techniques for making clothing, enabling them to make more tailored garments. These two factors, they say, may have helped modern humans to protect themselves from the radiation – while Neanderthals failed to do so.

It’s certainly a neat coincidence that the Laschamps event occurred so soon, barely 1000 years, before the last documented appearance of the Neanderthals. That does seem suspicious.
But we should also step back and look at the full 7-million-year history of humans and hominins. How many times has the magnetic field flipped out during that period, and did all those excursions and reversals cause havoc?
The answer is, it flipped out a lot. The most recent full reversal was the Brunhes-Matuyama reversal 795,000 to 773,000 years ago. That’s before the Neanderthals, but perhaps around the time of the common ancestor they shared with us. There have been several other reversals during the last 7 million years.
Excursions, which are smaller, are more common but also harder to pin down. A 2008 study looked at the last 2 million years and found 14 well-evidenced excursions (including Laschamps), plus an additional six with weaker support.
The upshot of all this is Neanderthals lived through at least three excursions before the Laschamps event, and possibly more. So why would the Laschamps event take them down after they’d survived all the other ones?
Likewise, if the Laschamps event was so dangerous it took out the Neanderthals, we would expect to see extinctions among other species too. In fact, large animals or “megafauna” were going extinct in Australia as early as 50,000 years ago, but survived in the Americas until much more recently, perhaps 13,000 years ago. There isn’t an obvious extinction spike around 42,000 years ago.
All of which makes me very wary of the Laschamps Event Neanderthal Extinction Hypothesis, as nobody is calling it. I don’t want to be too definitive – maybe it was a contributing factor – but I don’t believe it was the main cause.
The other claims of cosmic events influencing human evolution have similar problems.
Big boom
Take meteorite impacts. If you want to lose an afternoon down an internet rabbit hole, like I just did, go have a look at Impact Earth: a database of impact craters on Earth, presented as an interactive map. There you can learn about, for instance, the Zhamanshin hypervelocity impact crater in Kazakhstan, which is 13 kilometres across and 910,000 years old, or the 14-kilometre-wide Pantasma crater in Nicaragua from 804,000 years ago. Both dwarf the famous Barringer crater in Arizona, which is not quite 1.2 kilometres across and perhaps 61,000 years old.
Impact Earth lists 48 impact craters and deposits from the last 2.6 million years. If we go back to 7 million years ago, the approximate time of the first hominins, there are a few more. In chronological order:

Shunak, Kazakhstan, 7 to17 million years ago, 2.8 km across
Bigach, Kazakhstan, maybe 6 million years ago, 8 km across
Karla, Russia, 4 to 6 million years ago, 12 km across
Tsenkher, Mongolia, 4.9 million years ago, 7 km across
Roter Kamm, Namibia, 3.8 million years ago, 2.5 km across
El’gygytgyn, Russia, 3.65 million years ago, about 15 km across
Aouelloul, Mauritania, 3.1 million years ago, 0.39 km across

Bear in mind, these are just the ones we know about. Now, none of these compares to the Chicxulub crater, which is perhaps 200 kilometres across. The largest ones are between one-tenth and one-twentieth of that. Nevertheless, such impacts would still have significant consequences.
Of course, timing and location matter. Big impacts in Kazakhstan 6 or 7 million years ago probably didn’t disturb humans, because at that time hominins were confined to Africa. But I do wonder what hominins made of the Roter Kamm and Aouelloul impacts, both of which struck Africa when Australopithecus lived there. I couldn’t find any studies describing ecological consequences from either impact.
One more impact occurred around 790,000 years ago. It left distinctive melted rocks called tektites scattered over South-East Asia and Australia. A 2019 study linked it to a possible buried crater in Laos, which is about 15 kilometres in diameter. I suspect that might be too far east, and too early anyway, to have affected the Neanderthals. However, it must have been a significant event for the Homo erectus living in the area. But not too significant, given H. erectus survived as a species until between 117,000 and 108,000 years ago.
Dying stars
Supernovae emit huge pulses of matter and radiationNASA/DOE/Fermi LAT Collaboration, CXC/SAO/JPL-Caltech/Stew​ard/O. Krause et al., NRAO/AUI
What about even more distant events, like exploding stars? When massive stars go supernova, they emit huge pulses of matter and radiation that expand out across the galaxy. We have known for years nearby supernovae can leave traces on the rock record, in the form of unusual isotopes of iron.
Actually nailing this down is quite tricky, but there do seem to have been a few within the last 4 million years. One reading of the data suggested two – 2.3 and 1.5 million years ago, respectively. Another study also found two, but 1.5 to 3.2 million and 6.5 to 8.7 million years ago. These days, researchers seem to be zeroing in on 2 to 3 million years ago as a period when Earth got hit by supernova radiation.
Naturally, researchers have speculated about possible effects. One suggestion, published in May, is extra cosmic rays from the supernova led to more global cloud cover and thus cooler temperatures, and this could have affected the australopithecines living in Africa at the time. Well, maybe.
Physicist Adrian Melott at the University of Kansas has spent the last 20 years on what he calls “astrobiophysics”: basically, investigating ways that events in space such as supernovae could have affected life on Earth. Most of it is about events long before the first hominins, but not all.

Melott has highlighted 2.6 million years ago, when the Pliocene Period ended and the Pleistocene began. At this time, large marine animals suffered an extinction event. Maybe a supernova was the root cause. Melott has suggested the supernova would have dosed the planet with muon particles, leading to climatic changes like more frequent wildfires and direct impacts such as higher cancer rates. However, the palaeontologists who identified the extinction instead linked it to a loss of productive coastal habitats.
That’s enough listing of threats from outer space. My point is simply there have been a lot of these seemingly-dangerous events over the course of human evolution. Yet there is a near-total lack of evidence that any of these events caused extinctions, either of hominins or of other species.
Consequently, I tend to think asteroid impacts, exploding stars and reversals of the planet’s magnetic field have only played small roles in the story of human evolution. Some of those meteorite impacts surely had significant local impacts – how could they not? But that’s not the same as wiping out a hominin species, or driving a new adaptation.
The next time you see an excitable headline about some cosmic event killing off the Neanderthals or the like, remember this – and take it with a big pinch of salt.

Neanderthals, ancient humans and cave art: France

Embark on a captivating journey through time as you explore key Neanderthal and Upper Palaeolithic sites of southern France, from Bordeaux to Montpellier, with New Scientist’s Kate Douglas.

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Carved figure of a face from the Amiens-Renancourt 1 site in FranceStephane Lancelot/Inrap
A miniature statue dating back 27,000 years from northern France may give us clues to how ancient hunter-gatherers of the time styled their hair.
The statuette was unearthed in 2021 from an open-air site about 140 kilometres north of Paris called Amiens-Renancourt 1, but has only just been described by scientists.

It has long hair that appears to be braided with a gridded pattern, which could represent hair netting or a unique hairstyle. This differs from statuettes found across central and eastern Europe, where the hairstyle or headpiece is shorter and covers most of the head, says Olivier Touzé at the University of Liège in Belgium, who wasn’t involved in the study.
The statuette’s unique hairstyle may reflect the fashion of the time and area. “This could be a cultural particularity that would never have been highlighted other than through these rare human representations,” says team member Clément Paris at France’s National Institute of Preventive Archaeological Research.
Radiocarbon dating of rock layers at Amiens-Renancourt 1 suggests the figurine is around 27,000 years old, making it part of the Gravettian period, which lasted from 33,000 to 26,000 years ago across Europe. After this period, hunter-gatherer populations left north-western Europe for nearly 10 millennia due to the very cold and dry conditions of the last glacial maximum, says Touzé.

“The presence of ornamentation or a sophisticated hairstyle emphasises the care devoted to the carving of this statuette,” says Grégory Abrams at Ghent University in Belgium, who wasn’t involved in the research.
Other excavations at the site unearthed several scrap fragments and more than a dozen additional figurines, including Venus figurines that represent women. “It appears that the site had a workshop dedicated to [statuette] production,” says Touzé.
But questions remain about the statuette and what it might reflect about the people who made it. “Thoughts and myths from prehistoric times leave few traces,” says Paris. “And when we do have traces, such as this statuette, their meaning remains enigmatic.”

Topics:ancient humans More

Carved figure of a face from the Amiens-Renancourt 1 site in FranceStephane Lancelot/Inrap
A miniature statue dating back 27,000 years from northern France may give us clues to how ancient hunter-gatherers of the time styled their hair.
The statuette was unearthed in 2021 from an open-air site about 140 kilometres north of Paris called Amiens-Renancourt 1, but has only just been described by scientists.

It has long hair that appears to be braided with a gridded pattern, which could represent hair netting or a unique hairstyle. This differs from statuettes found across central and eastern Europe, where the hairstyle or headpiece is shorter and covers most of the head, says Olivier Touzé at the University of Liège in Belgium, who wasn’t involved in the study.
The statuette’s unique hairstyle may reflect the fashion of the time and area. “This could be a cultural particularity that would never have been highlighted other than through these rare human representations,” says team member Clément Paris at France’s National Institute of Preventive Archaeological Research.
Radiocarbon dating of rock layers at Amiens-Renancourt 1 suggests the figurine is around 27,000 years old, making it part of the Gravettian period, which lasted from 33,000 to 26,000 years ago across Europe. After this period, hunter-gatherer populations left north-western Europe for nearly 10 millennia due to the very cold and dry conditions of the last glacial maximum, says Touzé.

“The presence of ornamentation or a sophisticated hairstyle emphasises the care devoted to the carving of this statuette,” says Grégory Abrams at Ghent University in Belgium, who wasn’t involved in the research.
Other excavations at the site unearthed several scrap fragments and more than a dozen additional figurines, including Venus figurines that represent women. “It appears that the site had a workshop dedicated to [statuette] production,” says Touzé.
But questions remain about the statuette and what it might reflect about the people who made it. “Thoughts and myths from prehistoric times leave few traces,” says Paris. “And when we do have traces, such as this statuette, their meaning remains enigmatic.”

Neanderthals, ancient humans and cave art: France

Embark on a captivating journey through time as you explore key Neanderthal and Upper Palaeolithic sites of southern France, from Bordeaux to Montpellier, with New Scientist’s Kate Douglas.

Find out more

Topics:ancient humans More

Ohn Bavaro Fine Art/Science Photo Library
Today we are alone. But just a few hundred thousand years ago, our ancestors shared the world with at least five other ancient human species, including diminutive hobbits and burly Neanderthals.
It may now be time to add to that list. As we report in “An incredible Denisovan skull is upending the story of human evolution”, there are growing calls to give species status to a group of ancient humans known as the Denisovans.
This is hardly a rushed decision, given that the first Denisovan fossils were identified 15 years ago. Ancient DNA extracted from these remains revealed that they belonged to humans with a discrete evolutionary history. But it also suggested that these mysterious ancient people had interbred with our own ancestors, leaving many researchers reluctant to consider them a separate species.Advertisement
However, some definitions of a species allow for interbreeding, as long as the species involved maintain a defined appearance. The problem was that we didn’t yet know what Denisovans looked like. But earlier this year, we learned that an unusually thickset ancient skull, unearthed in China, is associated with Denisovan DNA. With the confirmation that the Denisovans were distinct in appearance, it is easier to argue that they should be given a formal species name.

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It is possible that the Denisovans could help us work out why we were the last humans standing
“

Biologists’ desire to divide nature up into species is sometimes dismissed as mere stamp collecting, where the aim is to categorise organisms rather than truly understand them. But in this case, at least, there is value to the exercise. Anatomical evidence from the Denisovan fossils points to the intriguing possibility that these enigmatic humans were very closely related to our species – perhaps, in fact, more closely related than any other. That suggests we might gain a particularly clear insight into the early behavioural development of Homo sapiens by comparing them with the Denisovans.
At some point, our ancestors learned new behaviours that helped them outcompete all other human species. It is just possible that the Denisovans could help us work out how we came to be the last humans standing.

Topics:human evolution/ancient humans More

Some two millennia on, Christianity is still a dominant religionSam Pelly/Millennium Images, UK
DominationAlice Roberts (Simon & Schuster)
Alice Roberts’s latest book is something of a left turn. In her previous works Crypt and Buried, she fused expertise in osteoarchaeology – the study of preserved human bones – with more traditional historical approaches, such as the analysis of ancient texts. Technical science was interwoven with empathic and thoughtful discussions of the historical record as she aimed for, and often achieved, nuanced, three-dimensional portraits of past human lives and cultures.
In Domination: The fall of the Roman Empire and the rise of Christianity there is virtually no osteoarchaeology. The focus is much more on historical documents. That isn’t a criticism – Roberts is a careful and curious reader of history – but it just might take some fans by surprise.
Roberts’s topic here is the rise of Christianity from humble eastern Mediterranean sect to a religion with billions of adherents. How and why did it become dominant, when most faded away?
At the centre of the narrative is the Roman Empire. When Christianity emerged, the empire controlled almost all the lands around the Mediterranean, from Britain all the way to Syria. The Romans had many gods, but Christianity gradually became more popular. There are several obvious turning points. One was when Constantine I, who ruled from AD 306 to 337, decriminalised Christianity (and supposedly converted, but Roberts points out gaps in the evidence on that front). Another came when Theodosius I, who reigned from AD 379 to 395, made Christianity the state religion.
Roberts is sceptical about traditional explanations for this: that the ideas of Christianity were especially appealing, say, or that its followers were more dedicated. Such claims, she argues, are little more than Christian propaganda.

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The eternal truth is not theological: gods come and go, temples rise and fall – but business is always business
“

Instead, Roberts says the real secret to Christianity’s success is how swiftly it penetrated the upper echelons of Roman society. Jesus may have hung out with lepers and sex workers, but the evangelists who followed in his wake targeted moneyed Romans, soldiers and the educated elite. This recruitment effort succeeded wildly. “Early adopters were to be found, not among the rural, or even the urban, poor of the Empire – but among the urban middle and upper classes,” writes Roberts.
In the following decades and centuries, the church acquired a portfolio of moneymaking enterprises. As Roberts writes, “peel away the religious overlay and what you’re left with is a huge, sophisticated system of interconnected businesses: welfare, health, legal, agribusiness, shipping, education”.
The church also took on many state functions, especially charitable efforts directed at poverty. However, it did so in a way that looks distinctly cynical. “Christian charity,” writes Roberts, “was never intended to solve the problem of poverty.” Instead, it enabled the church to market itself to all levels of society: “The poor were to be told that they would reap rewards in heaven. The rich were to be told that the only way they’d get to heaven was by donating to the Church.”
This was a system built on steep social inequality. One can’t help but compare it to modern billionaires’ philanthropy.
Eventually, the entire Roman socioeconomic system was reorganised around the church, says Roberts. Elite, educated Romans pursued church careers, in part because they were lucrative.
When the Western Roman Empire collapsed, this elite aligned themselves with the new regimes but kept the system intact, and often retained their positions. “Whatever the rhetoric, whatever spiritual messages were being adduced, the entity as a whole is looking very much like Roman business, Roman society as usual,” writes Roberts. “The eternal truth is not theological: gods come and go, temples rise and fall – but business is always business.”
Domination is a little hard going at first: there are a great many names to keep track of, and the narrative jumps around in space and time. Everything shifts up a gear, however, once Roberts’s argument comes into focus. The result is an incisive, provocative and sometimes polemical account of one of the most important organisations in human history.
Michael Marshall is a writer based in Devon, UK

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DNA evidence indicates that a skull unearthed in Harbin, China, belonged to a DenisovanHebei GEO University
One of the biggest mysteries in human evolution has just been solved. In 2010, a groundbreaking genetic analysis revealed that east Asia was once home to a previously unknown group of enigmatic ancient humans. We knew them as the Denisovans, but until very recently, we had no idea what they looked like.
That has now changed thanks to a 146,000-year-old skull unearthed in Harbin, China, in mysterious circumstances more than 90 years ago. In June, we learned that it carries Denisovan DNA in the ancient gunk attached to the surface of a tooth, suggesting that the cranium belonged to this ancient relative of modern humans. The discovery shows that these hominins had an unusual combination of features: their faces were similar to ours, but they had thick brow ridges and lacked our tall foreheads.

This finding closes one chapter of the Denisovan story. But another has just begun – and it looks set to bring even bigger revelations. For one thing, we can expect a new name for this extinct hominin, with at least two rival proposals for what it should be. There will also be a battle over how to accommodate the Denisovans in our family tree, particularly given the suggestion that they are more closely related to living people than any other ancient human – potentially ousting the Neanderthals from their position as our sister species.
That controversial idea has big implications in the ongoing search for Ancestor X, the population that gave rise to modern humans. It will also prompt a scramble to learn more about Denisovan lives and behaviour – because it is only by studying our closest cousins that we can really understand how we differ from the other humans that once walked the planet.
The story of the Denisovans, in terms of our recognition of them, begins just a decade and a half ago. They have been a puzzle since their unconventional discovery in 2010. Unlike other ancient humans, all of which are defined by the physical features of their skeletons, these hominins were originally defined solely on the basis of unusual DNA signatures in a tooth and tiny finger bone – both now thought to be between 51,000 and 84,000 years old – found in Denisova cave in Siberia, Russia. That DNA turned out to come from a human lineage that was related to, but distinct from, the Neanderthals.
Interbreeding
Bence Viola at the University of Toronto, Canada, who was a member of the team that made the discovery, says the researchers considered placing the fossils in a new species: Homo altaiensis. They ultimately decided not to, in part because the DNA showed that ancestors of living humans had interbred with the mysterious lineage. We now know that there were several episodes of this interbreeding, and that some human populations – particularly in the islands of South-East Asia and Oceania – inherited between 4 and 6 per cent of their DNA from Denisovans.
“Species names are problematic when you’re looking at populations that are so closely related,” he says. The team opted instead to give the lineage an informal name – the Denisovans – which some researchers view as merely a population within our species, Homo sapiens.
There isn’t universal agreement that this was the correct decision, however. Species can be defined in dozens of ways, many of which allow for a limited degree of interbreeding with other species. This means, for instance, that many researchers argue that Neanderthals deserve to be considered as a distinct species – Homo neanderthalensis – despite evidence that they interbred with modern humans. In a study published last year, Andra Meneganzin at KU Leuven, Belgium, and Chris Stringer at the Natural History Museum, London, advocated for this position because the Neanderthals developed a unique set of physical features and exploited resources in a distinct way.
With such ideas in mind, Christopher Bae at the University of Hawaiʻi at Mānoa recalls being intrigued by the fact that the original Denisovan tooth and a handful of others from Denisova cave were strikingly large. They strongly reminded him of teeth associated with ancient human remains that had been unearthed in China during the 20th century. “I said that it was only a matter of time before the Denisovans were given a Chinese species name,” he says.
The trouble was, says Bae, that no existing names were available there. Researchers in China had traditionally opted for a simple, linear picture of human evolution and so chose to label any human fossils from the past 200,000 years as either H. sapiens or – if the fossil had a primitive appearance – archaic H. sapiens.

Today, most researchers in China think our evolutionary tree is more complicated. As such, when Xijun Ni at the Chinese Academy of Sciences in Beijing and his colleagues examined the Harbin skull and concluded it didn’t belong to a Neanderthal or a modern human, they were comfortable with placing it in a new species. In 2021, they named this species Homo longi, derived from a Chinese term meaning “dragon”.
A few years later, in 2023, Bae attended a scientific meeting in Novi Sad, Serbia, to discuss the human evolutionary tree. “We basically agreed that H. longi is OK,” he says.
Denisovan DNA discovery
So, with news earlier this year that the Harbin skull contains Denisovan proteins and there is Denisovan mitochondrial DNA in the tartar adhering to its single tooth, a strong case can be made for saying the Denisovans and H. longi are one and the same. But Bae doesn’t see it that way.
For a few years, he has suspected that H. longi wasn’t the only ancient human wandering around east Asia in the Stone Age. In particular, he points to fragments of hominin skulls from Xujiayao and Xuchang in north China that are between 100,000 and 200,000 years old. He says they would have accommodated truly enormous brains with a volume of 1700 to 1800 cubic centimetres – much larger than the 1350 cc of the average living human.
Last year, he and his colleague Xiujie Wu at the Chinese Academy of Sciences placed these fossils and some others in a new species named Homo juluensis, which Bae is convinced is where the Denisovans really belong.

“You just have to look at the molars,” says Bae. The unusually large teeth from Denisova cave are, he says, virtually indistinguishable from the teeth associated with the fossils he and Wu placed in H. juluensis. And while he accepts that the Harbin skull carries Denisovan-like DNA and protein signatures, he suspects that, if DNA can be extracted from some of the H. juluensis fossils, they will provide an even closer genetic match with the remains from Denisova cave.
As things stand, then, there are now three potential ways to think about the Denisovans. The research community may begin to refer to them as H. longi or as H. juluensis – or a decision may be made to continue using the informal term Denisovan on the assumption that they really belong in H. sapiens. Currently, there is no consensus, but one is needed, says Bae. “You have to give them some kind of name because otherwise it’s really difficult to have a conversation about the variation and the evolutionary history of these human groups.”
Names are particularly important in light of new research. In an as-yet-unpublished study, Ni and Stringer have teamed up, together with other colleagues, and used anatomical information from dozens of ancient fossils to reconstruct the evolutionary relationships among species in our human genus. The results led to a radical redrawing of our family tree (see diagram below). Traditionally, the Neanderthals have been viewed as the closest ancient humans to living people. But Ni and Stringer’s team concluded that Denisovans are more closely related to us than the Neanderthals are. According to their analysis, the Denisovans and modern humans last shared a common ancestor about 1.32 million years ago. The Neanderthals branched away from our evolutionary line earlier, around 1.38 million years ago.

Ni and Stringer won’t discuss their conclusions until the work is accepted for publication in a scientific journal, but many researchers consider them to be controversial, given they clash with the DNA evidence. Not only does that DNA evidence suggest that Neanderthals and Denisovans are equally closely related to living humans, it also implies that the divergence between the Neanderthal-Denisovan line and our own occurred between 500,000 and 700,000 years ago – far more recently than Ni and Stringer’s team found.
“It’s very clear from the genetic data that a major split between the lineages leading to modern humans on the one hand, and Denisovans/Neanderthals on the other, occurred within the last 500-700,000 years,” says David Reich at Harvard University.
That being said, Aylwyn Scally at the University of Cambridge says such divergence estimates depend to some extent on the methods used to analyse the genetic data. José María Bermúdez de Castro at the National Human Evolution Research Centre (CENIEH) in Spain also thinks there is wiggle room on the divergence date. “The last common ancestor may be up to 1 million years old,” he says.
Last common ancestor
Conventionally, it is believed that this Ancestor X was located somewhere in Africa. But if Denisovans – a group that seems to have been largely confined to east Asia – emerged from the Ancestor X population too, an African location might seem less likely.
Some researchers are already willing to entertain the idea that Ancestor X lived in Eurasia rather than in Africa. In a 2022 study, Bermúdez de Castro and María Martinón-Torres at CENIEH argued that south-west Asia might make more sense, particularly the Levantine region bordering the eastern Mediterranean Sea. “It’s the umbilical cord linking Africa to Eurasia,” says Bermúdez de Castro.

Ancestor X might even have existed further east. In their yet-to-be-published study, Ni and Stringer’s team took a fresh look at two complete, but slightly squashed, ancient human skulls found in Yunxian, central China, about 35 years ago. They used software to create an undistorted model of one of the skulls, and realised that its anatomy was almost exactly in line with that expected of Ancestor X. For instance, it has features of our modern human face coupled with a more primitive-looking braincase that originally housed a brain of roughly 1140 cubic centimetres – smaller than that of the average living human.
Moreover, its age – about 0.9 to 1.1 million years old – is roughly in line with the researchers’ estimate for when our last common ancestor with ancient humans roamed the world. As such, they reached a striking conclusion: this Yunxian skull came from a human very closely related to Ancestor X. What other researchers make of such a bold suggestion, however, remains to be seen.
Denisovan behaviour
With these ideas swirling around the research community, it has never been more important to understand the lives of the Denisovans. This is because assessing how much of a behavioural overlap there was between these ancient humans and our modern human ancestors could provide vital information about our own behavioural evolution.
But it is difficult to conclude much about Denisovan behaviour without excavating sites that they occupied. We have known since 2010 that Denisova cave is one such location, but ancient DNA indicates that Neanderthals and modern humans also occupied the cave at various times during the Stone Age. This complicates things when it comes to interpreting the artefacts unearthed there, which include plenty of stone tools, bone needles for sewing and even ancient jewellery, such as an ivory tiara and a bracelet of polished green rock. Simply put, we don’t know which Stone Age humans made those artefacts.
Other sites, however, are beginning to offer some insights into Denisovan lives. In 2022, for instance, a research team reported the discovery of a tooth with a Denisovan-like appearance in Tam Ngu Hao 2 – dubbed Cobra cave – in Laos. It suggested that some Denisovans adapted to humid tropical conditions quite unlike those found around Denisova cave – although such a conclusion was tentative given that it wasn’t possible to extract Denisovan-specific DNA or proteins from the tooth.
But it is Baishiya Karst cave on the Tibetan plateau that is emerging as perhaps the most important Denisovan archaeological site. A study published last year concluded there is DNA evidence that the Denisovans – and no other humans – sporadically occupied the cave between 160,000 and 60,000 years ago.
Excavations have yet to unearth anything as striking as the Denisova cave jewellery, but they are still revealing important information about the Denisovans. Perhaps most interesting is the fact that they occupied the cave at all given the extreme environment in which it is located. “It’s cold throughout the year,” says Dongju Zhang at Lanzhou University, China. “Snow covers the whole area in the wintertime, and you need a thick jacket even in July or August.”
This fragment of mandible bone, found in Baishiya Karst cave in 1980, now turns out to have been from a DenisovanDongju Zhang, Lanzhou University
Unsurprisingly, then, Zhang and her colleagues have found evidence that the Denisovans made fires inside the cave. It is also likely that they wore clothing to further protect themselves from the elements, with evidence that they skinned animals including the bharal (Pseudois nayaur), also known as the blue sheep. “We think they took the skins to cover their bodies and keep themselves warm,” says Zhang.
Adding to the challenges the Denisovans faced is that the site is 3200 metres above sea level. “I was at the cave last year for a scientific workshop and the lack of oxygen is shocking – I got a horrible headache,” says Viola. Astonishingly, there are now hints that the Denisovans took to even higher altitudes: in as-yet-unpublished work, Zhang and her colleagues have found evidence of an ancient archaeological site on the Tibetan plateau at about 3700 metres above sea level.
Hunting strategies
Finding food on the plateau can be difficult because prey is thin on the ground. This may explain why Zhang and her colleagues discovered that the Denisovans at Baishiya Karst cave hunted a wide range of animals, including large mammals like the bharal and snow leopards as well as rodents such as marmots, and even birds. “It seems they had to use all the animal resources available to them,” says Zhang. To do so, the Denisovans must have developed a range of hunting strategies, because each of their prey species had a unique suite of behaviours.
Collectively, these discoveries paint a picture of the Denisovans as remarkably adaptable. Indeed, some archaeologists have commented that their behavioural flexibility is strikingly reminiscent of modern humans.
But even as we are finding echoes of ourselves in the Denisovans, we are also identifying subtle ways in which we differed from them. For instance, the stable isotopes in fossil teeth – which can reveal information about the variety of plants and animals an individual ate – suggest that modern humans adapted to hunt and forage in the rainforests of south and South-East Asia tens of thousands of years ago. But a 2023 analysis of the suspected Denisovan tooth from Cobra cave in Laos indicates that our ancient cousins lacked the tools and skill set to do so: they seem to have hunted only on nearby savannahs, says Mike Morley at Flinders University in Australia.
Archaeological discoveries in the years ahead should help us more precisely define the similarities and differences between the Denisovans and modern humans. The odds of making such discoveries received a boost earlier this year. After analysing ancient proteins inside a jawbone dredged up off the west coast of Taiwan, a research team concluded that the bone came from a male Denisovan – providing the strongest fossil evidence yet that the Denisovans really did occupy a vast territory. “The geographic range for Denisovans was likely huge,” says Morley. “Just think how much more there must be to find.”

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