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    Ancient humans lived inside a lava tube in the Arabian desert

    Researchers exploring the Umm Jirsan lava tube system in Saudi ArabiaPALAEODESERTS Project, CC-BY 4.0 (https://creativecommons​.org/licenses/by/4.0/)
    Archaeologists have found evidence of human habitation within lava tubes for the first time, in the deserts of northern Saudi Arabia.
    Lava tubes are caves that form during a volcanic eruption. The surface of a river of lava cools and solidifies, while hot molten rock continues to flow beneath it. Eventually, lava drains out of the tube, leaving behind a tunnel.

    Mathew Stewart at Griffith University in Brisbane, Australia, and his colleagues excavated a trench inside Umm Jirsan. At 1.5 kilometres in length, it is the biggest lava tube in Saudi Arabia. The researchers discovered animal bones, stone tools and pottery stretching back at least 7000 years and possibly as much as 10,000 years.
    Stewart and his team have worked in the region for more than 15 years and have previously found numerous stone structures on the surface, confirming human habitation. However, the desert’s hot, arid climate has caused organic material to break down, making it difficult to date.
    On the surface, the landscape is a “hot, dry and flat basalt desert”, says Stewart. “But when you are down in the lava tube, it’s much cooler. It’s very sheltered and it would have been a great place of refuge.”
    “It’s transforming our understanding of the prehistory of the Arabian peninsula,” he says.
    In parts of the underground network at Umm Jirsan, the researchers also found human bones, but these are thought to have been dragged in by hyenas.
    In other lava tubes nearby, Stewart and his colleagues found rock art, including representations of domestic sheep and goats that would have been made by “cultural contemporaries” of the groups using the lava tubes as a refuge, he says.
    Mike Morley at Flinders University in Adelaide, Australia, describes the lava tubes as being like “prefabricated activity spaces”.
    “As a scientist who works primarily in caves, I am excited that we have another type of cave system being used by past human populations,” says Morley. “These finds represent a treasure trove of archaeological information for Arabia, a massive region that has only recently been investigated systematically for prehistoric archaeology.”
    Lava tubes have also been suggested as possible places for humans to shelter on the moon and Mars.

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    Untangling the enigmatic origins of the human family’s newest species

    Callao cave in the Philippines, where fossils from Homo luzonensis were foundFlorent Detroit/Callao Cave Archaeology Project
    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.
    On 10 April 2019, our extended family got a bit bigger. A study in Nature reported the discovery of a new species of hominin called Homo luzonensis, from the Philippines. My colleague and fellow fossil enthusiast Colin Barras wrote about it for New Scientist.
    It’s been five years since the announcement,… More

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    Stone Age blades could have been used for butchery, not just hunting

    Prehistoric stone blades called Clovis points could have been used as weapons – or butchery toolsMetin I. Eren
    Stone “Clovis points” used by prehistoric hunters to kill animals are also remarkably efficient at cutting meat off a large animal carcass – at least according to a modern bison butchering experiment. The finding complicates our knowledge of prehistoric hunting practices.
    Archaeologists teamed up with modern hunters to compare how well replicas of two types of prehistoric stone tools could harvest meat from an animal carcass. They used a humanely killed bison bull weighing more than 450 kilograms.

    “This study actually showed that Clovis points were more effective than what was presumed to be the butchery tool: large stone flakes,” says Metin Eren at Kent State University in Ohio.
    The five hunters, associated with the MeatEater outdoor lifestyle company, took just 3 hours and 10 minutes to completely butcher the bison carcass using both stone tools. But the Clovis points achieved a butchering efficiency of 0.38 kilograms of meat per minute, whereas the handheld stone flake tools processed 0.34 kilograms of meat per minute.
    The Clovis points, which were mounted on wooden handles, had the added benefit of not injuring any users, whereas four out of five experts suffered minor cuts while using the handheld stone flakes.
    But the Clovis points also required frequent resharpening during the butchering – and three of the 10 stone tools broke. “They demonstrate that the Clovis points work well, but they also demonstrate that the Clovis points break a lot,” says John Shea at Stony Brook University in New York, who was not part of the study. “And this is important because those things are not easy to make.”
    Still, prehistoric peoples in the Americas may have adopted “such a labour-intensive and breakage-prone artefact” as part of social displays of group cooperation and stone working skills, says Shea.
    Field processors butcher the bison with stone tools, while recorders take notes on how they use themSeth Morris
    Another surprise came from how a Clovis point snapped and broke in a way that was nearly identical to how another Clovis point on an atlatl weapon broke when hurled at an elephant carcass in a previous study. “The possibility of snap breaks being mistaken for impact breaks is an eye-opener from the standpoint of interpreting how Clovis points might have been used,” says Vance Holliday at the University of Arizona, who did not participate in the study.
    That means broken Clovis points discovered at prehistoric archaeological sites may not represent a “smoking gun for hunting”, as researchers previously believed. They could instead show how people “came across an already dead animal and scavenged it”, says Eren. In other words, deducing prehistoric hunting and scavenging behaviours just got a lot more complicated.

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    The Biology of Kindness review: Living well and prospering

    What is the impact of being kind on our bodies and lifespan?Kara McWest / Stockimo / Alamy
    The Biology of Kindness
    Immaculata De Vivo and Daniel Lumera, translated by Fabio De Vivo
    MIT Press (first published in Italian in 2020)
    We tend to think about kindness as a quality that helps others, not ourselves. But a new book, The Biology of Kindness: Six daily choices for health, well-being, and longevity, unpicks the impact of being kind on our bodies and lifespan, as well as the effect of four other traits and behaviours – optimism, forgiveness,… More

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    The unexpected reasons why human childhood is extraordinarily long

    Rene Bernal/Unsplash
    I WAS going to start this article another way. But that was before my 10-year-old daughter intervened. In fact, I had already begun writing when she bounced up and tried to scam me. She offered to bet me £10 that she could make an ordinary pencil write in the colour red. Alas for the budding entrepreneur, I refused the bet: she was too confident, so I suspected she had something up her sleeve. But I did let her reveal her trick. She took a lead pencil and wrote “in the colour red”. Then she laughed like a hyena and went off to try scamming her mother.
    Our bright little spark has opinions about everything from video games and sports to books. She is learning basic algebra and coding, and her Taylor Swift expertise vastly outstrips mine. Yet, despite all this knowledge, she has years to go before adulthood. If she lives an average lifespan, a quarter of her years will be spent underage.

    The long human childhood is a real oddity. No other primate spends so much time becoming an adult. Over the course of our species’ evolution, along with more obvious physical changes, childhoods got vastly longer. Traditionally, palaeoanthropologists have paid little attention to children, but now that is changing. A spate of intriguing discoveries in the past few years is building a picture about human childhood: when this seemingly unproductive life stage expanded, why it is so long and what prehistoric kids got up to. The findings don’t just throw light on a dark corner… More

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    Medieval horses buried in London had far-flung origins

    International trade may have helped medieval elites acquire the best horses for jousting tournamentsPRISMA ARCHIVO / Alamy
    Horses owned by the elite in medieval England were probably imported from continental Europe, possibly travelling hundreds of kilometres, according to tooth analysis of horses unearthed at a cemetery in London.
    In the 1990s, commercial excavators stumbled across an unusually large horse burial site in central London. Subsequent digs at the site, now known as the Elverton Street cemetery, have uncovered 70 whole or partial horse remains. Some of the graves have been dated to between 1425 and 1517, but the cemetery may have been used over a wider period.

    “It’s medieval Britain’s only real, good example of a horse cemetery,” says Oliver Creighton at the University of Exeter in the UK. “We usually find [horse remains] scattered across archaeological sites in very small numbers.”
    To learn more about the origin and lives of these medieval horses, Creighton and his colleagues collected and analysed the molars from 15 horses buried at the site.
    Plants from different parts of the world contain varying levels of carbon, oxygen and strontium isotopes – atoms with different numbers of neutrons. When an animal eats these plants, these isotopes accumulate in their bones and teeth over time. So, by analysing the chemical signatures of the horses’ teeth, the team could pinpoint where they probably came from.
    This revealed that at least seven came from abroad, possibly from Scandinavia or the western Alps, says Alexander Pryor, also at the University of Exeter.
    “These were also some of the largest medieval horses yet discovered in the UK,” says Pryor, which suggests that English elites may have sought out the best horses from Europe.
    The arrangement of their teeth seemed to suggest the use of a special mouthpiece typically reserved for horses groomed for battle or jousting tournaments.
    “There’s a good chance the horses could have come from the jousting arena at Westminster Palace, which was just a kilometre away,” says Creighton.
    “The nature of horse teeth – with very high crowns that develop over quite a long time – gives them huge potential for studies using isotopes to track movements over the course of an individual horse’s life,” says David Orton at the University of York, UK. “But this is the first paper I’ve seen that really seems to make full use of that potential.”

    Topics:archaeology/history More

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    Why falling birth rates will be a bigger problem than overpopulation

    The cost of housing and fertility treatments may deter people in high-income countries from having childrenER Productions Limited/Getty Images
    Think of global population problems and you might think of the growing number of people in the world – currently about 8 billion – and our collective toll on the planet. But due to people having fewer children as countries become more prosperous, the real demographic problem may turn out to be falling populations.
    Projecting from current trends, demographers have now predicted that, within about 25 years, three-quarters of countries will have birth rates that are too… More

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    Ancient canoes hint at bustling trade in Mediterranean 7000 years ago

    The canoes are up to 10 metres long and made from hollowed out treesGibaja et al., 2024, PLOS ONE, CC-BY 4.0
    More than 7000 years ago, skilled craftspeople constructed wooden canoes that probably transported people, animals and goods across the Mediterranean Sea.
    Scientists have identified five boats with signs of advanced seafaring technology, such as transverse reinforcements and towing accessories. Found in a freshwater lake, the canoes – which have been somewhat of an inadvertent secret for decades – probably enabled trade and transportation among Mediterranean farming communities during the Neolithic period, says Niccolò Mazzucco at the University of Pisa in Italy.
    Along with the well-preserved village they were found in, the canoes “open a window to the past”, he says.Advertisement

    In 1989, Italian researchers discovered the site – which they named La Marmotta – buried under a lake located 38 kilometres upstream from the western coast of the Mediterranean Sea, slightly north-west of Rome. In addition to multiple wooden buildings, they found dugout canoes built from trees that had been hollowed by burning and carving.
    Despite these findings, language barriers kept them from becoming well-known internationally, with nearly all related information published only in Italian, says Mario Mineo at the Museum of Roman Civilization in Rome, who participated in the discovery.
    Now, Mazzucco, Mineo and their colleagues have taken a fresh look at these canoes using modern methods – and shared their results in English.
    Lasse Sørensen at the National Museum of Denmark, who wasn’t involved in the research, says he was unaware of these boats, despite his extensive work with dugout canoes in Scandinavia.
    He is particularly intrigued by the wooden T-shaped devices found with the canoes. The holes drilled into them suggest they were probably used for ropes, which implies the boats were towed. This would have allowed them to transport “more people, more animals, more stuff”, says Sørensen. “So, these details are really important because they’re actually a testimony of how they could have transported a lot of goods.”
    The team used recent carbon dating technology to place each boat’s origins in the 6th millennia BC: the two oldest were built as early as 5620 BC and the most recent one as late as 5045 BC. Carbon dating one of the T-shaped accessories revealed it was made as early as 5470 BC.

    The boats are up to 10 metres long. This size suggests they were used on the sea, says Mazzucco. Recent tests of replicas of these canoes confirmed the originals would have been seaworthy. Foreign grains, livestock remains and stones found at the village indicate the villagers traded across the Mediterranean region.
    To identify the trees used to make the boats, the team sliced off nine thin samples of wood from each canoe. Analysing these under a microscope, the researchers determined that two of the boats – including one of the oldest – were made from alder, which is lightweight and doesn’t split or crack easily. The most recent boat was made from oak, which is tough and resistant to decay, while the remaining two boats were made from poplar and beech.
    “They probably had enough knowledge about wood species and their properties to choose them and to use them on the basis of those properties,” says Mazzucco. “These people were working wood with the same knowledge as a carpenter today, just with different tools.”

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