Humans

An archaeological site in the lowlands of Ethiopia where ancient humans lived 74,000 years agoJohn Kappelman
An campsite in what is now Ethiopia may have been used for a few years before, during and after a huge volcanic eruption 74,000 years ago that altered Earth’s climate.
The eruption of Toba, a supervolcano on the Indonesian island of Sumatra, was the biggest eruption on Earth in the past 2 million years. Some researchers think it caused a volcanic winter that lasted several years and might have wiped out most humans alive at the time, but the magnitude of its impact is disputed.

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Bones found at a site in Ethiopia suggest that the people living there had to adapt their diet to survive during a drier year or two after the eruption, but the impact appears to have been mild.
“It was a pretty lucky find,” says John Kappelman at the University of Texas at Austin, whose team discovered the site in 2002. “There is no question about it.”
Most early human sites are caves that were occupied for tens of thousands of years, he says. But this camp is an open-air site near the Shinfa river, a tributary of the Blue Nile. “Our hunch is that this site was occupied for maybe five to 10 years, something like that,” says Kappelman.
The team has found thousands of stone chips from the making of tools, along with some stone points that may be among the oldest arrowheads ever found. “We have evidence for archery in the form of these little stone points,” says Kappelman.
The researchers have also discovered ostrich egg shells and the bones of many animals, some of which have cut marks and signs of heating. So they think people were bringing animals back to the site to butcher and cook.
In the middle of the layer of sediment containing the stone chips and bones, the team also found volcanic ash in the form of minuscule pieces of glass known as cryptotephra. “They are just tiny, tiny glass shards,” says Kappelman – and their composition matches others from the Toba super-eruption.
An isotopic analysis of the ostrich shells suggests that the climate became drier after the eruption. This coincides with a quadrupling in the amount of fish remains seen and a decrease in other kinds of animal remains.
The team’s explanation for this is that the Shinfa river is seasonal and dries up, leaving waterholes in the dry season. Immediately after the Toba eruption, the dry season was longer, so the fish in the shrinking waterholes were easier to catch. This made up for the fall in terrestrial prey animals, the researchers suggest.
In the following years, food remains returned to pre-eruption levels, with no sign of a mass die-off, says Kappelman.

Other researchers have argued that when conditions got drier, early humans moved to places that were wetter, he says. For this reason, it is also thought that the migration of people out of Africa took place during periods when the climate was wetter, allowing them to survive in the usually arid regions between Africa and Eurasia.
“Our site shows that humans were adapted to seasonally arid conditions,” says Kappelman. This means that the movement of modern humans out of Africa, which may have taken place as recently as 65,000 or 60,000 years ago, could have happened during dry periods, he thinks.
However, Kappelman agrees that earlier migrations out of Africa by less sophisticated peoples may have been limited to wetter periods.
“This is an intriguing paper for many reasons – the possibly precise tie-in with the Toba super-eruption, the environmental evidence, subsistence behaviours including fishing, possible use of bow and arrow, and behavioural adaptations that might have facilitated dispersals from Africa,” says Chris Stringer at the Natural History Museum in London.
“I’m sure each of these propositions will fuel debate, but I think the authors have made a plausible – though not definitive – case for each scenario they propose,” he says.
The study also adds to the growing evidence that the global impact of the Toba super-eruption was relatively minor and short-lived, says Stringer.
But Stanley Ambrose at the University of Illinois Urbana-Champaign, one of the researchers who thinks Toba wiped out most humans, disagrees. He says the site may represent a much greater period of time than Kappelman’s team thinks, meaning the effects on people may have been much greater.
“Materials deposited by humans long before and long after the eruption – possibly centuries to more than a millennium earlier or later – could be juxtaposed with the ash layer by well-known processes of disturbance, such as burrowing rodents and cracks that form during the dry season,” says Ambrose.

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The 1000-year-old brain of an individual excavated from a churchyard in Ypres, Belgium. The folds of the tissue, which are still soft and wet, are stained orange with iron oxidesAlexandra L. Morton-Hayward
A study of human brains that have been naturally preserved for hundreds or thousands of years has identified 1300 cases where the organs have survived even when all other soft tissues have decomposed. Some of these brains are more than 12,000 years old.
“Brains of this type, where they’re the only soft tissue preserved, have been found in sunken shipwrecks and in waterlogged graves where the bones are just floating,” says Alexandra Morton-Hayward at the University of Oxford. “It’s really, really strange.”

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“We’re not expecting a brain to preserve in any type of environment, to be honest,” she says. “If, as an archaeologist, I dig up a grave and I find a brain rattling around in a skull, I would be shocked. But particularly, we’re not expecting soft tissues to preserve in waterlogged environments.”
Morton-Hayward first became interested in brain preservation while working as an undertaker. “The brain is known to be one of the first organs to decompose post-mortem. I saw it liquefy pretty quickly. But I also saw it preserve,” she says.
Many researchers have noted that human brains are found preserved more often than expected and in surprising circumstances, says Morton-Hayward. Now, she and her colleagues have done the first ever systematic study of the phenomenon. They have put together a database of more than 4400 preserved human brains found all over the world.
They have also collected and studied many preserved brains themselves. “I did put one in an MRI machine, which was a terrible mistake. I didn’t realise how much iron was in there,” says Morton-Hayward.
In most cases, the brain preservation could be explained by known processes. For instance, the brains of Incan human sacrifices entombed on top of a volcano in South America around AD 1450 were freeze-dried along with the bodies, says Morton-Hayward.
The bodies and brains of bog people such as Tollund Man, who was hanged and dumped in a bog 2400 years ago in what is now Denmark, were preserved by a tanning process similar to that used for leather.
And saponification, where fatty substances turn into a form of soap called grave wax, preserved the brains of some people shot in 1936 during the Spanish Civil War and buried in a mass grave.
But the known processes preserve all soft tissues, not just brains. They don’t explain the 1300 cases where brains are the only soft tissue to survive.
“This unknown mechanism is completely different,” says Morton-Hayward. “The key feature of it is that we only have the brain and the bones left. There’s no skin, no muscle, no gut.”
For instance, Saint Hedwig of Silesia was buried in Poland in 1243. When her body was exhumed in the 17th century, her brain was found to be preserved, which at the time was attributed to divine power.
Alexandra Morton-Hayward holding a 1000-year-old preserved brainGraham Poulter
Morton-Hayward’s working hypothesis is that, in certain circumstances, substances such as iron can catalyse the formation of cross-links between proteins and lipids, forming more stable molecules that resist degradation. The nature of the proteins and lipids found in brains, or their ratio, might be the key.
“The mechanisms are similar to those that we see in neurodegenerative diseases, like dementia,” she says. “So if we can figure out what’s happening to brains after death, we might be able to shed some light on what’s happening in brain ageing in life as well.”
“It is fantastic news that the data is being published,” says Brittany Moller at James Cook University in Melbourne, Australia, one of the researchers who has found that brain preservation is more common than thought. “It may increase awareness among researchers of the likely potential for brain material preservation,” she says.
That is important because preserved brains often have the same colour as surrounding soil. “It is therefore highly likely that brain material is frequently discarded during archaeological excavation as it is not recognised for what it is,” says Moller.
While the study focused on human brains, the findings should apply to animals too. There are at least 700 instances of animal brains preserved in fossils, says Morton-Hayward, with the oldest being arthropods that are half a billion years old.

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An intact hafted axe found under one of the structures that burnt down at the Must Farm siteCambridge Archaeological Unit
The remains of a Bronze Age settlement in eastern England have been exquisitely preserved after being destroyed by a fire 3000 years ago. An examination of the site gives us an extraordinary snapshot of how Britons lived at the time, from what people may have eaten for breakfast to the tools they used to build houses.
Archaeologists first stumbled across ancient wooden posts at Must Farm quarry, near the small town of Whittlesey, in 1999. The small-scale investigations that followed sought to figure out whether there was anything interesting there, says Chris Wakefield at the University of York in the UK. But it wasn’t until 2015 that Wakefield and his colleagues conducted a full-scale excavation of the site.

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The team uncovered the structural remains of four large roundhouses – circular dwellings usually made of wood with thatched conical roofs – dating back to between 3000 and 2800 years ago. Wooden stumps suggest these were built on stilts, connected by wooden walkways, over a small river that ran through the area. Based on the size of the channel, there may have been about 10 roundhouses at the settlement, says Wakefield.
Tree-ring analysis on wood from the structures suggests the settlement was destroyed a year after its construction, with the houses falling into the muddy water below. The waterlogged, oxygen-scarce environment prevented the settlement from degrading, preserving it in unprecedented detail, says Wakefield. Charring on the objects from the fire also provided a protective layer against environmental decay. “Pretty much everything that had been there in time of the fire inside these people’s houses has been preserved to find nearly 3000 years later,” says Wakefield.
The way items fell into the mud gave clues to the layout of each house. As you step through the door, the kitchen area tended to be in the east side of the house, with a sleeping area in the north-west and pens for livestock in the south-east.
Chemical analysis of kitchenware, including pots, bowls, cups and jars, suggests that the settlement’s prehistoric inhabitants probably ate porridge, cereals, honey and stews made with beef, mutton and fish.
“This is the best evidence we have on understanding prehistoric diet and cooking practices,” says Rachel Pope at the University of Liverpool in the UK. “It’s the closest we’ll ever get to walking through the doorway of a roundhouse 3000 years ago and seeing what life was like inside.”

Illustration depicting daily life in one of the Must Farm structuresJudith Dobie/Historic England
Toolboxes filled with axes, sickles and razors were a staple in every household. “One of the most beautiful objects that one of my colleagues found was an incredible two-part hafted axe,” says Wakefield. “What was so amazing about this particular design is that the axe head itself was inserted into an extra bit of wood that you could swap out.”
The garments recovered at the site have a lush, velvety feel – they were made of some of the finest textiles produced in Europe at that time, says Wakefield. Decorative beads, which may have been used in necklaces, were also found across the site, possibly coming from elsewhere in Europe or the Middle East.
The settlement has been likened to the ancient Roman town of Pompeii, which was entombed in ash after a volcanic eruption in AD 79. “Archaeologists sometimes talk of a Pompeii-like discovery – a moment frozen in time – and this is one of those, a burnt-down settlement that gives us an intimate view into people’s lives just before the fire and in the months running up to it around 2900 years ago,” says Michael Parker Pearson at University College London.
“Must Farm is more than a once-in-a-generation site. It is very likely that there will never be a site that tells us more about Bronze Age Britain,” says Richard Madgwick at Cardiff University, UK.

Topics:archaeology/ancient humans More

A wooden tablet from Rapa Nui with Rongorongo glyphs carved into itSilvia Ferrara
This is an extract from Our Human Story, our newsletter about the revolution in archaeology. Sign up to receive it in your inbox for free every month.
When we think about the invention of writing, we generally think about Eurasia and Africa. It might bring to mind Mesopotamia in western Asia and the invention of cuneiform, or perhaps Egyptian hieroglyphics.
As a rule, we don’t think about isolated Pacific islands. But maybe we should. On Rapa Nui in… More

jonkrause.com
LIFE, it could be argued, is like a long game of blackjack. In one common version of this, each person is initially dealt two playing cards. The aim is for your hand to add to 21, or as close to this as you can get without busting. Players can either “stick” with their existing hand or “twist” – asking to be dealt another card to add to their total. The risk, of course, is that you exceed 21 and are eliminated.
This may sound far removed from everyday choices, but many of our most important life decisions boil down to such dilemmas. Should I stay put or take the leap and move house? Should I remain in my job or start my own business? Should I put up with an unsatisfying relationship or try my luck at love another time? In each case, we must weigh the security of what we have against a riskier, but potentially more rewarding, alternative.
The inherent uncertainty of these dilemmas leaves many of us dithering in analysis paralysis, so that we end up lingering in the status quo, never giving ourselves the chance to win big. Some people, in contrast, are too easily swayed by the lure of the new: they gamble too readily, until their impulsive behaviour has lost them everything. If either of these scenarios sounds familiar, help may be close by. Thanks to a growing understanding of our underlying cognitive biases and how to escape them, we now have evidence-based strategies to think about these quandaries more rationally – and so play the hand life has dealt us to our best advantage.
… More

jonkrause.com
LIFE, it could be argued, is like a long game of blackjack. In one common version of this, each person is initially dealt two playing cards. The aim is for your hand to add to 21, or as close to this as you can get without busting. Players can either “stick” with their existing hand or “twist” – asking to be dealt another card to add to their total. The risk, of course, is that you exceed 21 and are eliminated.
This may sound far removed from everyday choices, but many of our most important life decisions boil down to such dilemmas. Should I stay put or take the leap and move house? Should I remain in my job or start my own business? Should I put up with an unsatisfying relationship or try my luck at love another time? In each case, we must weigh the security of what we have against a riskier, but potentially more rewarding, alternative.
The inherent uncertainty of these dilemmas leaves many of us dithering in analysis paralysis, so that we end up lingering in the status quo, never giving ourselves the chance to win big. Some people, in contrast, are too easily swayed by the lure of the new: they gamble too readily, until their impulsive behaviour has lost them everything. If either of these scenarios sounds familiar, help may be close by. Thanks to a growing understanding of our underlying cognitive biases and how to escape them, we now have evidence-based strategies to think about these quandaries more rationally – and so play the hand life has dealt us to our best advantage.
… More

Aboriginal people use fires to manage the landscapePenny Tweedie/Getty Images
Indigenous Australians have been managing the environment with fire for at least 11,000 years, according to an analysis of sediment cores retrieved from an ancient lake.
Michael Bird at James Cook University in Cairns, Australia, says the findings suggest that a return to an Indigenous regime of more frequent but less intense fires could reduce the risk of catastrophic bushfires and improve environmental management.

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It has long been known that Australia’s first peoples, who are thought to have been on the continent for 65,000 years, carefully managed the landscape with fire to make it easier to move around and hunt prey. They also figured out that this benefited some animals and plants that they preferred and reduced the risk of more dangerous fires.
However, it has been difficult to establish how long this has been happening for, says Bird. That is because most waterways completely dry out in the dry season each year and the carbon in their sediments is destroyed.
Girraween Lagoon, near Darwin in the Northern Territory, is a massive sinkhole covering an area of about 1 hectare that has stayed permanently wet for at least 150,000 years. As the climate changed over millennia, so, too, did the vegetation around the sinkhole. “From Girraween Lagoon, we have got 150,000 years’ worth of sediment that has never dried out,” says Bird.
By analysing sediment cores from the lagoon’s bed, Bird and his colleagues were able to study three key metrics: the accumulation of micro-charcoal particles, the proportion of burnt material in the charred vegetation matter and a measure of the amount of the different kinds of carbon that remain after burning.
The first two metrics allow researchers to infer the intensity of fires, while the third indicates whether fires were cool enough to leave traces of grasses preserved.
Prior to the arrival of people, natural fires in the savannahs of northern Australia were ignited by lightning late in the dry season, when vegetation and the landscape had almost fully dried out. This kind of higher-intensity fire combusts biomass more completely, particularly fine fuels such as grass and litter, leaving less charred remains from grasses.
Indigenous fire regimes, on the other hand, burn frequently but with much less heat, affect small areas and are limited to the ground layer, promoting a mosaic of vegetation and helping to protect biodiversity.
Bird says the more recent layers in the cores show clear evidence of more frequent fires and grasses that haven’t been fully combusted, indicating cooler fires. These kinds of fires are a sharp departure from the previous natural pattern of fires and provide the tell-tale fingerprint of Indigenous fire management, he says.
Researchers collect sediment cores at Girraween Lagoon in Northern Territory, AustraliaMichael Bird
This signal can be seen in sediments dating back to at least 11,000 years ago, the study found, but before that point the metric for the proportion of grasses and tree remains becomes harder to study. Bird says there are hints of a human burning signal from as early as 40,000 years ago, but the evidence isn’t as clear-cut.
“It means that for at least 11,000 years, the savannah has grown up with humans,” he says. “The biodiversity has grown up with that fire regime. Take that kind of burning away and you start to see significant problems with biodiversity.”
David Bowman at the University of Tasmania, Australia, says the paper highlights the twin importance of climate and humans in shaping fire regimes.
“Separating climate from anthropogenic – and importantly Indigenous – fire management is a hugely important topic,” he says. “We are battling to counteract climate-driven wildfires globally and such a deep-time perspective will be an invaluable addition to current research and development of sustainable fire management.”

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Korolevo quarry in Ukraine, one of the oldest hominin sites in EuropeRoman Garba
Molecular dating has revealed that an area in Ukraine was occupied by humans 1.4 million years ago, making it one of the oldest hominin sites in Europe and possibly the oldest.
The site, at Korolevo in western Ukraine, has been studied since the 1970s. A large number of stone tools have been found buried in layers of sediment beside an outcrop of volcanic rock suitable to be made into tools.

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“This was like a magnet for bringing the people there, and they were camping nearby,” says Roman Garba at the Czech Academy of Sciences in Prague.
No bones have been found as the soil is too acidic to preserve them, he says, but it is assumed that the hominins were Homo erectus, a species that evolved around 2 million years ago and spread from Africa to Europe and Asia.
While it has been clear that early hominins were present at the Korolevo site repeatedly over hundreds of thousands of years, we haven’t known exactly when they were present. But Garba’s team has now dated the oldest layer containing tools to 1.4 million years ago, using a technique called cosmogenic nuclide dating.
This method relies on cosmic rays that are so energetic that they can split the nuclei of atoms and generate unusual isotopes. However, these isotopes form only on exposed areas, as these cosmic rays don’t penetrate far into solid objects.
Once objects are buried, radioactive isotopes generated by cosmic rays decay into other isotopes, allowing the time of burial to be determined.
Another early hominin site in Dmanisi in Georgia has been dated to 1.7 million years ago, while other sites in France and Spain are around 1.2 million years old. This suggests that early humans moved from Africa through Georgia and into Ukraine, then west into the rest of Europe, says Garba, though it is also possible that some crossed the Bosphorus Strait in Turkey.
It has been suggested that some hominins crossed the Gibraltar Strait to reach Spain when sea levels were lower than present, then moved east into the rest of Europe, but there is no evidence to support this, says Garba.

While part of Georgia is in Europe geographically and the whole country is seen as part of Europe politically, the site of Dmanisi is geographically located in Asia, says Garba. So he and his team regard Korolevo as the oldest human site in Europe that has been reliably dated.
“Korolevo represents, to our knowledge, the earliest securely dated hominin presence in Europe,” the paper states.
“I agree that the new age estimates are important, and they support the idea of an early east-west dispersal,” says Chris Stringer at the Natural History Museum in London.
But this was already apparent because four other sites in western Europe have already been dated to around 1.4 million years ago, he says.
Garba says that while it is possible that these other sites are as old, the dating of them is questionable. “We can’t be as sure about them,” he says. “They are not secure or not robust.”
“I respectfully disagree,” says Stringer.

Topics:archaeology/ancient humans More