Philippa Kaur

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    in Humans

    The 2023 discoveries that made us rethink the story of human evolution

    Stone age paintings in Chauvet cave in FranceFine Art Images/Heritage Images/Getty Images
    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.
    At this point it’s a truism that the story of human evolution is being rethought. Discoveries in recent years have forced us to rethink many crucial points, such as how old our species is – about 300,000 years old as opposed to 200,000 – and what extinct hominins like the Neanderthals were really like.
    2023 was equally dizzying: discoveries continued to come thick and fast. But because there are so many species and eras involved, it’s hard to discern the common threads linking them – at least, beyond “we found out some more stuff”.Advertisement
    However, I do think it’s possible to draw out some overall messages from the blizzard of archaeological finds. Two things stand out to me. One is the growing evidence that many supposedly “advanced” behaviours, such as architecture and art, can be traced much further back in time than we thought, often to hominins that existed before modern humans. And the other is that we have badly misunderstood gender roles in prehistoric societies, imposing patriarchal values onto cultures that had very different ideas about how women should behave.

    Ancient achievements
    Let’s start with architecture. At Kalambo Falls in Zambia, researchers found buried logs that had been shaped with stone tools so that they interlocked. They seem to have once been part of a larger structure, perhaps a building. Which would be unsurprising if they weren’t 476,000 years old. That’s almost 200,000 years before our species, Homo sapiens, evolved.
    Extinct hominins also managed to settle in extreme places. For instance, we now know that hominins like the Denisovans lived on the frigid heights of the Tibetan plateau 200,000 years ago – upending the old notion that the plateau was only settled by modern humans around 3600 years ago.
    Art also seems to have been invented by older hominins. We already had evidence that Neanderthals painted on cave walls, and 2023 saw more Neanderthal art from La Roche-Cotard cave in France. Even earlier species like Homo erectus may also have made art, for example by engraving patterns on shells.
    By far the most contentious claim in this area is that Homo naledi made art. H. naledi lived around 250,000 years ago, making it a contemporary of our species. However, it had quite a small brain, typical of older hominins – and was therefore, according to palaeoanthropological dogma, incapable of complex behaviours.
    Nevertheless, in the Rising Star cave system in South Africa where the H. naledi remains were found, researchers have found what seem to be etchings on the cave walls, though these have yet to be firmly dated. They also claim to have found evidence of H. naledi burying their dead in the cave. These assertions were the subject of a Netflix documentary, Cave of Bones.

    To say these claims are controversial is to understate the situation. Many researchers say the evidence presented so far is completely inadequate to support them. The dispute has only been heightened by the way the results were released, in a non-traditional journal that publishes peer reviews publicly alongside the paper.
    My views on the H. naledi controversy are complicated. I do think more evidence is needed: in particular, I want to know how old the engravings are. At the same time, I think the species’ small brains are a distraction. Palaeoanthropologists got fixated on brain size because it was what they could see: if what you have is skeletons, then all you know about brains are their shapes and sizes. But other properties like the brain’s internal wiring are surely equally important and may explain how a species like H. naledi could do complicated things despite their small brains.
    In a sense, we shouldn’t be surprised that so many of these behaviours had their origins in older, extinct hominins. Evolution usually works by gradual steps, and so does technology – the first birds weren’t great at flying, and the first mobile phones weren’t great at, well, anything really.
    The idea that there was a sudden explosion of intelligence and creativity at some point in our evolution isn’t inherently ridiculous: sometimes a system hits a tipping point and undergoes runaway change. But there was never that much evidence that human evolution worked this way. Instead, it seems that Homo erectus, the Neanderthals and many others all walked so we could run.

    Alternative societies
    One way or another, the H. naledi story is going to be an example of letting our preconceptions get in the way of the evidence. The same is true for our ideas about gender in prehistory. Archaeology was invented by societies with sexist ideas, and those notions bled into the research (see also: scientific racism and homophobia). Researchers are now trying to unpick this stuff, and 2023 saw some significant steps.
    Perhaps the most dramatic was the demolition of “Man the Hunter”. This was the idea, promoted for decades, that in most prehistoric societies the men went out to hunt and the women stayed home. However, a meta-analysis published in June compiled data on several dozen foraging societies and found women hunted in 80 per cent of them. In line with this, it emerged that an ancient spear-throwing tool called an atlatl enables women to launch projectiles at the same speed as men.

    We have also seen growing evidence of women occupying positions of power in ancient societies. The Viking queen Thyra may have helped unify Denmark in the 900s. Going further back, an Iberian leader from around 4000 years ago turned out to be female, not male as many had assumed, when proteins in her teeth were analysed.
    So I want to end 2023 on a hopeful note. The more we learn about past societies, the more our preconceptions about the ways society “has to be” turn out to be wrong. Inequality, authoritarianism and patriarchy aren’t inevitable. They’re choices, and prehistory shows us that we can choose differently.

    Topics: More

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    in Humans

    What makes the best sounding didgeridoo, according to science

    Didgeridoo players can use their vocal cord reverberations to manipulate the resonances produced by the woodKate Callas
    The traits that make the best didgeridoos have now been identified, and it has also given us a better understanding of how people use their vocal cords to make sounds with the instruments.
    Didgeridoos, used by the Indigenous peoples of northern Australia for at least 1500 years, are “the principal musical instrument of the world’s oldest continuous culture”, say John Smith and Joe Wolfe, both at the University of New South Wales in Australia.… More

  • 150 Shares189 Views

    in Space & Astronomy

    How tiny red stars can test ideas about the origin of life

    A survey of small, cool stars is helping to narrow in on the conditions that might set the stage for life beyond our solar system.

    A look at about 200 ultracool dwarf stars shows that they lack sufficient ultraviolet light intensity to have the potential to jump-start life, researchers report December 1 in the Monthly Notices of the Royal Astronomical Society. That may initially seem to be bad news for finding signs of alien life on distant planets. But the diminutive stars could instead serve as test beds to determine what other conditions can create the chemical foundations of life.

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    Compared with our sun, the dwarf stars in the new study are minuscule, roughly the size of Jupiter and weighing about a tenth as much as the sun. They’re also among the most common types of stars. And because they’re cool and comparatively dim, it’s often easier to spot planets orbiting them than it is in the glare of large bright stars. Astronomers studying the tiny red star TRAPPIST-1, for example, found that it hosts seven Earth-sized planets, including three that may be within the star’s habitable zone, where conditions are amenable to life (SN: 2/22/17).

    For life to exist on a habitable planet, though, it must start somehow. One possibility is that UV starlight provides the energy needed to link together the hydrogen, oxygen, carbon, nitrogen, sulfur and other atoms that make up the compounds that are precursors to life.

    With that in mind, space scientist Antígona Segura and colleagues used the Transiting Exoplanet Survey Satellite to measure the amount of UV radiation — among other things — emitted from 208 comparatively nearby ultracool dwarfs within 130 light-years from Earth (SN: 4/12/18). The stars they studied do emit UV light, as our sun does, and many produce bursts of UV when they let off flares. But overall, the UV energy the small stars release is too low to forge the chemicals needed to kick-start life, the team found.

    The dearth of UV light doesn’t necessarily quash hopes of finding life around such stars. “UV is an energy source for prebiotic chemistry that we can measure, and that is why we focused on it,” says Segura, of the National Autonomous University of Mexico in Mexico City. “But there are many other energy sources, like cosmic and stellar particles, and particles, radiation and heat produced by radioactive decay, to name a few.”

    Ultracool stars might be useful to discover whether something other than UV light can get life going. “We should search for life on the planets that have the least [UV] activity, where we can know with confidence that UV-driven prebiotic chemistry cannot happen,” says Paul Rimmer, a University of Cambridge astrophysicist who was not involved in the study. “If we find evidence of life on these [types of] planets, this will show that there are other paths to life.”

    Also, Segura notes, sources of energy that could start life can also make planets less habitable for more complex life-forms. “We cannot currently say which [effects] would prevail. The best approach now is to study case by case and wait for more observational constraints, like for the case of the TRAPPIST-1 system.”

    If astronomers eventually find life on planets orbiting ultracool dwarfs, it will confirm the potential for UV-free origins of life. But, Rimmer says, if it turns out that there are no signs of habitability on planets around the many small, dim dwarf stars we see, that would lower estimates of the likelihood of finding life outside our solar system. Either way, future surveys of ultracool dwarf stars could give researchers a better handle on the possible prevalence of extraterrestrial life in the universe. More

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    The US needs to do more to preserve its ancient sites

    Elaine Knox
    IN OCTOBER, the US Department of Homeland Security made an urgent announcement. New barriers and roads were needed along the Texas-Mexico border – but construction was impeded by federally mandated surveys and permits. These protect the environment and archaeological sites. They also take time to complete. To speed construction, the Biden administration waived compliance with 26 federal laws, eight of which regulate archaeological and/or sacred Indigenous sites.
    In 1888, it was looters, not governments, who were barrelling through the past. Anthropologists Alice Fletcher and Matilda Stevenson knew the looters were winning. They proposed legislation to preserve US archaeological sites on… More

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    Stonehenge science: How archaeology reveals the stone circle’s secrets

    Stonehenge was built between 3000 and 2000 BC and is one of the world’s most famous prehistoric monuments. Each year, the site attracts thousands of visitors during the summer and winter solstices. Whether used for ceremonial, astronomical or spiritual events, Stonehenge remains a subject of intrigue. Now, using the latest scientific technologies such as radiocarbon dating and 3D laser scanning, archaeologists are understanding how this colossal stone circle was built and what its purpose was, as well as gaining new insight into how our Stone Age human ancestors lived. New studies even suggest some of the stones could align with the moon during rare lunar events.
    Read more: We’ve finally figured out where Stonehenge’s giant boulders came from

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    Vaping vs edibles: How does the way we use cannabis alter its effects?

    Cannabis edibles offer a different way to consume the drugShutterstock/Brian Goodman
    For people who want their cannabis without the smoke, edibles provide an increasingly popular alternative. And it isn’t just pot brownies, either. Gummies, tinctures and other products can be laced with the drug.
    “The availability of different types of products makes it so that there’s something for everyone,” says Jibran Khokhar at Western University in Canada.
    [special_article_unit title=”The science of cannabis” description=”As the use of marijuana and its compounds rises around the world, New Scientist… More

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    Traces of cannabis found in pre-modern human bones for the first time

    A femur, one of the bones that held traces of cannabisGaia Giordano, Mirko Mattia, Michele Boracchi, et al.
    The first evidence of cannabis discovered in archaeological skeletal remains comes from bones of people buried under a hospital in Milan, Italy, in the 17th century.
    “Molecules of medicinal plants can be detected by toxicological analysis even centuries after the death of an individual,” says Gaia Giordano at the University of Milan in Italy.
    She and her colleagues discovered molecules of tetrahydrocannabinol (THC) and cannabidiol (CBD) – the psychoactive components of cannabis – within the thigh bones of a young man and middle-aged woman who had been buried between 1638 and 1697. Such molecules can be trapped and preserved after being absorbed into the bloodstream and travelling through blood vessels into bone tissue.Advertisement
    Giordano and her colleagues extracted bone samples from the remains of nine people. The individuals were buried in a crypt at Milan’s Ca’ Granda hospital in the 17th century, and the researchers confirmed this using radiocarbon dating.
    They then performed toxicology analyses by powdering and preparing the bone samples so that individual chemical compounds could be separated and purified within a liquid solution. This let them use mass spectrometry to identify the chemical components.

    The science of cannabis

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    The researchers did not find any mention of cannabis in the Ca’ Granda hospital’s records of medicinal compounds. So, Giordano says the people may have been self-medicating or using the cannabis recreationally, instead of receiving it as a prescribed treatment.
    The study is unique in using this toxicology method to analyse human remains at an archaeological site, says Yimin Yang at the University of Chinese Academy of Sciences in Beijing. “I think their study will open a new window for researching cannabis consumption in ancient times,” he says.

    Yang’s own research previously found chemical traces of cannabis on wooden braziers in tombs dating back 2500 years ago. And cannabis has an even longer history of becoming humanity’s favourite weed, starting with its domestication around 12,000 years ago.
    Meanwhile, Giordano and her colleagues are expanding their toxicological search to other substances, such as cocaine, in more modern human remains.

    Topics:archaeology/Cannabis More