Humans

Porc-Epic cave in EthiopiaA. Herrero
A huge stash of reddish minerals from a cave in Ethiopia shows how Stone Age people gradually adapted their technologies and practices over a 4500-year period.
“It’s one of the rare sites where we can see a very precise evolution of this cultural feature through thousands of years,” says Daniela Rosso at the University of Valencia in Spain.
Rosso and her colleagues studied materials from Porc-Epic cave in Ethiopia. The cave first became known to scientists in the 1930s, and was thoroughly excavated in the 1970s. It was used by people in the Middle and Late Stone Age, between about 80,000 and 40,000 years ago, but the bulk of archaeological material dates from a 4500-year-long period about 40,000 years ago.Advertisement
This material included 4213 pieces of “ochre” – an umbrella term for minerals that are rich in iron and consequently have vivid colours, typically red. Prehistoric people often collected these minerals, but the original excavators of Porc-Epic did not study them. “This is the first time there is a systematic study of ochre use at this site,” says Rosso.

Rosso and her colleagues examined what the various pieces of ochre were made of. This changed over time: ochre from the beginning of the 4500-year period was typically high quality and rich in iron, while ochre from the end of the period was lower quality and had less iron. The later ochre was also coarse-grained, so instead of grinding it to powder the people tended to chip and cut it.
There are several possible explanations for the shift. One is that the people at Porc-Epic may have been using the ochre for different purposes as time went on, and chose different types accordingly.
The most famous use of ochre is as a pigment for artworks, but Rosso says it was probably sometimes used in utilitarian ways – for making adhesives, or as sunscreen, for example.
However, running counter to the idea that the shift was deliberate is evidence in a 2022 study by Rimtautas Dapschauskas at the University of Tübingen in Germany and his colleagues. They reviewed all known uses of ochre in Africa from 500,000 to 40,000 years ago. Dapschauskas says prehistoric people consistently sought out “fine-grained and blood-red materials”, which were the best for pigment as they could be ground to a very fine powder and produced vivid colours. “People really, really preferred those reddish colours,” he says.

So it may be that, as time passed, the people at Porc-Epic simply found it increasingly difficult to source the best-quality ochre. The team examined local geological deposits and found that the available ochres did not match those in the cave: they were often coarser-grained and had less iron. “Probably they had to go further away” to find the best ochre, Rosso says.
Why it became harder to get the high-quality ochre is unclear, says Dapschauskas, but it may be that the social situation changed: for instance, if the people at Porc-Epic relied on trade to secure good-quality ochre, then conflict with neighbouring groups might have led to shortages.
The study adds nuance to our understanding of technological stasis in the Stone Age, says Dapschauskas. “There’s a form of stability,” he says. “The cultural knowledge is transferred from generation to generation to generation.” But at the same time, the people were flexible and changed their practices over time. “They can really trace several thousands of years of behavioural change.”

Topics:archaeology/Stone Age More

The limestone spheroids of ‘Ubeidiya, roughly the size of baseballs, seem to have been deliberately shapedLeore Grossman
An analysis of 150 round, baseball-sized stones found at a site where early humans lived 1.4 million years ago shows that they were intentionally knapped into spheres. This rules out the idea that they became round after being used as hammers, but doesn’t tell us why they were shaped.
“Unfortunately, we still can’t be confident about what they were used for,” says Antoine Muller at the Hebrew University of Jerusalem.

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Signs of ancient occupation at ‘Ubeidiya, in what is now northern Israel, were discovered in 1959. A few human bones and thousands of stone tools have been uncovered there. The site is thought to have been used by some of the first members of our ancestor species Homo erectus to move out of Africa.
The finds include nearly 600 stone balls made of flint, basalt and limestone. Similar discoveries have been made at many other early human sites dating as far back as 1.8 million years ago. The objects, known as spheroids, were made by knapping, but why this was done remains a mystery.
It has been suggested that they are a byproduct of the creation of other stone tools, or that they are stones deployed as hammers that became round as they were used rather than being deliberately shaped.
To test this idea, Muller and his colleagues scanned 150 limestone spheroids from ‘Ubeidiya, which are of varying degrees of roundness and around 8 centimetres in diameter, roughly the size of a baseball. They worked out the sequence of strikes responsible for each ball’s shape.

The researchers conclude that these spheroids required similar levels of skill and planning to make as hand axes, rather than being accidental creations. But the team can’t say if the same is true of any other spheroids, says Muller.
“Clearly, whoever made these objects was working hard to make them spheres,” says Andrew Wilson at Leeds Beckett University, UK, who in 2016 showed that the shape and weight of typical spheroids are suitable for throwing.
“To my mind, this certainly looks more like they were crafting projectiles than, say, hammers,” says Wilson. “I know from my work that these rocks would make good hunting weapons for a group of humans.”

Topics:human evolution More

The shoes of a kneeling archer from the Terracotta ArmyDavid Davis Photoproductions RF/Alamy Stock Photo
Shoes worn by the warriors of the first emperor of China, famously depicted by the Terracotta Army, were surprisingly flexible and slip resistant, according to a reconstruction of the ancient footwear. The replicas help build a better picture of what Qin dynasty soldiers may have worn and how they might have aided them in battle.
The Terracotta Army was discovered in 1974 near Xi’an, China, and is formed of more than 8000 sculptures depicting the armies of the founder of … More

An ancestral population of humans was reduced to very low numbers, according to a genetic analysisThe Natural History Museum/Alamy
The population of our ancestors may have plummeted to as low as 1300 around 900,000 years ago, possibly as a result of our ancestral species splitting from other early humans.
That is the conclusion of an analysis of the variation in the genomes of living people by Haipeng Li at the Shanghai Institute of Nutrition and Health and his colleagues. However, while not dismissing the idea outright, independent experts say it isn’t supported by other lines of evidence.
Population bottlenecks occur when an existing population is reduced in size, for instance as a result of a catastrophe or when a small number of individuals leave one population to found a new one. This results in a sudden loss of genetic diversity.Advertisement
There have been numerous bottlenecks of varying scales as humans evolved and moved around the world. For instance, there was a major bottleneck when a small number of modern humans left Africa around 60,000 years ago, which is why there is still much more genetic diversity among people of African descent than in everyone living in the rest of the world combined. Much more recently, there was a series of bottlenecks as Polynesians settled island after island in the Pacific.
Past bottlenecks can be uncovered by looking for the reductions in genetic diversity they cause, but more ancient bottlenecks are harder to detect than recent ones. Li’s team developed a new method for estimating past changes in population size and applied it to the genomes of more than 3000 people from around the world.
According to the researchers’ findings, the population of our ancestors fell by 98 per cent to around 1280 “breeding individuals” around 930,000 years ago, and the population remained very low until around 815,000 years ago.
The early humans alive at this time have been assigned to a number of different species, including Homo heidelbergensis, Homo rhodesiensis, Homo antecessor and Homo bodoensis, and it is unclear which of these is our ancestor. There is also debate about whether they were indeed separate species.
Li and his colleagues think this bottleneck was most likely due to climate change, with global cooling around this time leading to severe drought in Africa and Eurasia. This “could explain the extreme scarcity of the available hominin fossil record in Africa and Eurasia” at the time, they write in their study.
Li says this is referring to previously published studies that have reported a gap at this time. “We didn’t find the fossil gap in this study,” he says. “Our findings actually explain the fossil gap.”
But in an accompanying paper, Nick Ashton at the British Museum and Chris Stringer at the Natural History Museum in London have put together a list of sites in Africa and Eurasia with evidence of continued human habitation during this time.
“The combined evidence, using several independent methods, seems strong,” says Ashton. “A global event seems unlikely as this would have affected populations in Eurasia as well as Africa.”
“The data of human presence that we marshalled suggest that its effects must have been limited in time and space,” says Stringer.
Li’s team also cites a paper by Brad Pillans at the Australian National University as evidence of drought in Africa and Eurasia at the time of the bottleneck. “We said nothing about aridity in Africa,” says Pillans. “So, in a way, the reference to our paper is not really correct.”

John Hawks at the University of Wisconsin, who wasn’t involved in the study, points to a paper from earlier this year suggesting that early humans in Africa were split into several distinct populations with only occasional migrations and mergers between them. It is possible that this population structure resulted in the appearance of a bottleneck, says Hawks.
Li’s team notes that the time of the bottleneck coincides with estimates for when two existing chromosomes fused to form chromosome 2. This is why humans have only 23 pairs of chromosomes rather than the 24 of chimpanzees and gorillas.
Another explanation for the bottleneck is that rather than there being a sudden reduction in population due to drastic climate change, it reflects a speciation event where a small number of individuals split away from other early humans after chromosome 2 evolved.
“The possible link to chromosome 2 is very interesting, and I think it may be true. But I would not assume that the bottleneck is real until we have a better understanding,” says Hawks. “It would be great to see more ancient DNA data that could get us back into this time period.”

Topics:human evolution More

A limestone jar containing the remains of internal organs taken from the body of Senetnay, an ancient Egyptian womanChristian Tepper/Museum August Kestner, Hannover
Eternity smells like a concoction of beeswax, bitumen, plant oil and tree resin. That’s according to researchers who have just analysed the ingredients used to embalm an ancient Egyptian noblewoman – Senetnay – who died about 3500 years ago.
Sniffing out the products used during mummification not only helps us better understand how the ancient Egyptians treated their dead, but also what trade routes they relied on to access unusual ingredients.
Senetnay is said to have nursed Amenhotep II, a pharaoh of ancient Egypt’s 18th dynasty – a dynasty that also included famous rulers Tutankhamun and Hatshepsut. Senetnay was buried in the Valley of the Kings near the ancient town of Thebes, the modern-day city of Luxor.Advertisement
Barbara Huber at the Max Planck Institute of Geoanthropology in Germany and her colleagues used state-of-the-art analytical technology — such as gas chromatography-mass spectrometry — to unpack the chemical composition of the balm residue found in two of the jars that held Senetnay’s organs during the mummification process.
This is the most complex mummification balm found from this period in ancient Egyptian history, according to Huber, and the scent extracted from it is so sophisticated that she dubbed it “the scent of eternity”.
“The dominant smell, I would say, is like this strong pine-like woody scent of the conifers. But then it’s also a little bit intermingled with a sweeter undertone of the beeswax,” she says. “And then we have this kind of strong smoky scent of the bitumen. It’s a little bit like freshly laid tar on a street.”
But it’s the tree resins, specifically, that interested Huber’s team. Their analysis suggests the balm probably contained resin from larch trees. It may also have contained resin from pistachio trees, or perhaps a so-called dammar gum.
These three ingredients aren’t naturally found in Egypt, as larches and pistachios mainly grow in the northern Mediterranean, and dammar comes from trees that grow in South-East Asian forests. This suggests that ancient Egyptians were importing goods via far-reaching trade routes at an earlier date than researchers had previously thought. For instance, a study published earlier this year also found dammar in a mummification balm used in ancient Egypt, but Senetnay’s mummy predates that example by a thousand years.

“If the ingredients are what they say they are, it suggests a much more connected world than we might otherwise have thought,” says Sean Coughlin at the Czech Academy of Sciences, who was not involved in the study. “We might wonder what equipment, skills, and ideas would have traveled with them along the trade routes.”
Huber has unanswered questions about whether these balms were selected for specific reasons — perhaps because they work as antimicrobials or insecticides. She also wonders whether different organs were mummified using different balms, as her initial data suggests, and if this was an intentional choice that carried some significance.
“Data for embalming materials for the 18th dynasty are lacking, so this is a very welcome addition to the corpus of information,” says Kate Fulcher, who formerly analysed embalming material at the British Museum and was not involved in the study.
“We don’t know much, or anything really, about who conducted the ceremony and what was said,” Fulcher says. “This appears to have been secret or controlled knowledge and we don’t have any writing about it.”

Topics:chemistry /archaeology More

AP Photo/Richard Lewis/Alamy
WITHOUT fossils, we would struggle to understand the ancient roots of humanity. Yet it is easy to overlook the circumstances surrounding their discovery, which may carry additional significance. The way fossils are found can tell its own story, one that can remain hidden from view or skewed in its reporting. But as we reveal in our feature “The untold story of the curiously controversial Homo floresiensis dig“, it is never too late to uncover the truth.
For instance, the 146,000-year-old Harbin skull, which hit the news two years ago, may overturn long-accepted ideas concerning the origin of our species. However, … More

The skull of Homo floresiensisJAVIER TRUEBA/MSF/SCIENCE PHOTO LIBRARY
ON A Tuesday in early September 2003, Benyamin Tarus struck bone. Digging through a cave floor on the Indonesian island of Flores, his trowel sliced into the left eyebrow ridge of an ancient human skull.
It soon became clear that Benyamin had uncovered evidence of an extinct, diminutive human relative unlike anything scientists had seen before. It was given the name Homo floresiensis and nicknamed the hobbit.
The find was described as “the most significant discovery concerning our own genus in my lifetime” by one researcher, and justifiably so. H. floresiensis promised to overturn established ideas about the shape of our prehistoric family tree and the importance of big brains for the success of ancient humans. As importantly, the bones showed that south-east Asia had been a hotbed of ancient human evolution.
You might expect that Indonesian researchers would have been as excited as anyone by the discovery on their doorstep. You would be wrong. After H. floresiensis was announced to the world, a leading Indonesian archaeologist condemned the international reporting of the discovery as “unethical”. A few days later, he surprised his colleagues by helping another Indonesian researcher take possession of the bones. When they were returned several months later, some were damaged beyond repair.
It has long been a mystery to many people why the Indonesian scientists reacted so strongly. My research can help. I have spent six years digging into the H. floresiensis story and talking to Indonesian scientists. Not only do I now have a greater appreciation of the scientific … More

There are many great science and technology podcasts at the momentShutterstock/AnnaStills
There are so many science podcasts out there that choosing one can feel overwhelming. We’ve scoured the internet for classics and little-known gems covering a wide range of topics from space to food to cybercrime. Here are our top picks.

Should you switch to a gluten-free diet? Is artificial intelligence really out of control? This podcast digs into trends and hot topics in the news to expose the science behind them, separating fact from fiction. In a typical episode, science journalist Wendy Zukerman, the creator and host, talks to scientists and experts and cites research in the field in a style that is upbeat and engaging. The idea for the show came about in 2015 when actor Gwenyth Paltrow suggested that women should steam their vaginas for an energy boost, to rebalance hormones and keep clean. Zukerman felt compelled to bust the myth and has been fact-checking fads on her show ever since.

You’ve probably heard of RadioLab. Launched in 2002, the award-winning podcast, currently co-hosted by science journalists Lulu Miller and Latif Nasser, recounts a different science or technology-related story every week, often exploring different angles. The show incorporates interviews with experts and first-person accounts by guests into captivating narratives. Recent episodes have delved into a strange internet law that lets tech companies off the hook for what happens on their platforms, the cause of the mysterious Tunguska impact that hit Siberia in 1908 and whether disabled people could actually be the ideal astronauts. Highly recommended for curious people with diverse interests.Advertisement

It might just be the best podcast name out there. With weekly episodes, the official podcast of NASA’s Johnson Space Center in Houston, Texas features in-depth conversations with astronauts, scientists and engineers about the latest developments in human spaceflight. The show just celebrated its 300th episode with special guests talking about what the future holds for humans visiting low-Earth orbit, recorded in front of a live audience. Previously, the show has discussed NASA’s near-term goal to establish a sustainable human presence on the moon’s surface. It often focuses on different aspects of this plan, such as new lunar spacesuits and the first space station to orbit the moon being developed by NASA, called Gateway, which is aiming to support long-term human visits as well as deep space exploration. Each instalment is typically about an hour long, allowing for topics to be covered in detail.

Want to take a deep dive into a specific branch of science? The podcast’s name stems from the suffix ‘ology’ – the study of something – and consists of long chats between host Alie Ward and experts on diverse and often obscure disciplines, from sciuridology (the study of squirrels) to diabetology (the research and treatment of diabetes). Ward poses questions that bring out little-known aspects of each field while also touching on personal aspects, such as how guests chose their speciality, which often leads to interesting stories.  The idea for the podcast was sparked by the word curiology – writing with pictures. Ward recently dedicated two episodes to this field by delving into emojis, from the origin of the smiley face to behind-the-scenes drama and stats on usage and trends. I give it a thumbs-up.

A generation of young people is now grappling with the climate crisis – often considered to be the most pressing problem humanity is currently facing. This podcast, which is in its third season, is produced by and for young people and aims to bring their stories to light. While early episodes focused on the experiences of young climate activists, the show is now broader in scope. In the latest episode, storyteller Reece Whatmore imagines a world in which buildings are conceived in collaboration with nature, rather than having human-made materials dominate city landscapes, and talks to biomaterial designers, scientists and engineers who are working to accomplish this goal. By being solution-focused, Inherited tackles a daunting topic in a hopeful way.

Food collides with science and history in this bi-weekly podcast co-hosted by journalist Cynthia Graber and author Nicola Twilley. In the most recent episode, the pair examines where fungi and bacteria in a sourdough starter come from by taking part in an experiment in Belgium with microbiologists and bakers. The show also delves into farming, for example by looking at how human faeces could save agriculture and the planet, and new developments, such as lab-grown meat, which made its debut in a US restaurant in July. The show often takes inspiration from listener requests and is sure to fascinate inquisitive food-lovers.

Efforts to undo human-induced damage to wildlife by allowing nature to take over again, called rewilding, have taken off in in recent years. In this podcast hosted by James Shooter, a photographer and filmmaker, listeners are taken behind the scenes of various rewilding initiatives across Europe as he travels to visit them during a year-long trip. Monthly episodes tell the stories of people trying to recover nature, for example experts in the Greater Côa Valley in Portugal, who are trying to improve the co-existence of animal species such as rabbits, Iberian wolves and dung beetles. The host’s passion for conservation makes the show both informative and engaging.

Through the ages, people have often tried to treat medical problems in odd, disgusting or simply ineffective ways. Hosts Sydnee and Justin McElroy, a doctor and comedian, respectively, were therefore inspired to create a podcast that uncovered some of these proposed treatments by digging through the annals of medical history. With new episodes out every Friday, the show also looks at the latest therapeutic fads, such as a pungent plant resin, called asafoetida, which some claim can has a range of medical benefits, and an egg-shaped sound-therapy chamber called a Harmonic Egg. The latest instalment examines the sudden recent uptick of cases of leprosy in Florida, looking at the history of the disease and current treatments. May not be suitable for squeamish people.

A true crime show for tech geeks. Hosted by Jack Rhysider, who was previously a network security engineer, the podcast showcases stories about the dark side of the internet told by hackers and those who have been hacked. In a recent episode, a member of the Dominican Republic’s cybersecurity incident response team explains the process he went through when he investigated a major cyberattack aimed at his country’s government. Another instalment follows a man who breaks into buildings for a living to test whether they are secure or not. The show is compelling and binge-worthy.

It is shameless self-promotion, but you may just enjoy our podcasts too. New Scientist Weekly, our flagship show hosted by Timothy Revell and Christie Taylor, takes a closer look at the most fascinating science news stories of the week. If you’re looking for something a bit more off-beat, Dead Planets Society explores crazy ideas such how we could punch a hole in a planet or whether we could destroy the sun – from a physics perspective, of course. And we’ve also got CultureLab, a podcast that could be interviewing the world’s most exciting authors about fascinating books one week and delving into the science behind a movie or TV show another. All available on the main New Scientist Podcasts feed.

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