DNA samples collected from Inca mummies have confirmed the presence of a strain of smallpox that first emerged in Europe.

“We interpreted this as the first direct molecular evidence of smallpox introduction into the Americas through European colonisation,” says at Trinity College Dublin, Ireland.

Smallpox was the scourge of humanity for centuries until its eradication in the 1980s, through vaccination, from all but a few high-security medical laboratories. Severe strains of the virus had a mortality rate of up to a third and left survivors with scars from the blisters and scabs that cover the skin and fill with pus.

The disease was particularly brutal in parts of the world colonised by Europeans, such as and the Americas, where Indigenous populations had no natural immunity, resulting in millions of deaths.

In the Americas, historical reports record that smallpox began devastating Indigenous communities in the early 16th century, after the arrival of European colonists.

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at the University of Dundee in the UK, who wasn’t involved in the new research, says the waves of epidemics, including smallpox, that spread across the Americas were some of the most important events in history. “These diseases killed perhaps 95 per cent of the Indigenous population of the Americas and allowed for European colonisation,” he says.

Nakagome and his colleagues studied samples of bone from mummies found at an archaeological site known as Camarones 9 in northern Chile, discovered in 1957. Over subsequent decades, 41 mummified bodies wrapped in blankets and buried with grave goods were recovered from the site.

“While the original aim was to study the human DNA, we also searched for DNA from ancient pathogens,” says Nakagome. “That is when we discovered fragments matching the smallpox virus in two individuals.”

The first was a woman who was 30 to 35 years old at the time of death, and the second, an 18-to-20-year-old man, was revealed by carbon dating to have died between 1492 and 1631.

By reconstructing the virus’s genomes and comparing them with other ancient and modern smallpox viruses, the team found that they belonged to a lineage of smallpox that includes early medieval and early modern European strains.

The discovery adds weight to the possibility that small skin lesions on the trunks of the mummies, previously attributed to chronic arsenic exposure, may in fact have been the distinctive pustules that scar the skin of smallpox victims.

“This finding allowed us to identify a small group of people impacted by the virus for which no historical record exists,” says team member at the University of Chile in Santiago. Before the new research, the pathogen was known only from historical accounts of large-scale outbreaks, she says.

The work was particularly sensitive because of the disturbance of the original remains and the loss of material during analysis, both considered extremely controversial subjects to Indigenous people and the scientific community. “We never forget that behind every DNA extraction is a person, not a data point,” says de la Fuente Castro.

Ward welcomed the new research. “Understanding exactly what was killing native peoples and why they were so susceptible to epidemic disease is a vitally important issue,” he says.

Historians are now trying to understand how Europeans deliberately or inadvertently fuelled the spread of epidemics like smallpox, he says. “Without these epidemics, colonisation of the Americas would have been very different.”

A tiny, long-necked marine predator that lived 245 million years ago is the oldest reptile ever found with an intact digestive system.

The exquisitely preserved fossil, including almost the entire skeleton as well as the stomach, liver and intestines, was found in Yunnan province in China in 2023 and is named Austronaga minuta.

Even blood vessels and the scales of a partially digested fish meal are visible in the remains.

“A fossil this age with such clear preservation of its organs is really a world treasure,” says at Flinders University in Adelaide, Australia, who wasn’t involved in the research.

Austronaga dates back to the Triassic Period, when dinosaurs first evolved, but it isn’t a dinosaur. It belongs to a broader group called archosaurs, which includes dinosaurs, birds and crocodiles, but not other famous marine reptiles like mosasaurs or ichthyosaurs.

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The archosaurs were incredibly diverse in the Triassic and included “all kinds of interesting and strange-looking reptiles”, says at the Natural History Museum Stuttgart, Germany, a member of the team that analysed the fossil. Only later, during the Jurassic and beyond, did they become more restricted, mostly being limited to dinosaurs, including birds, and crocodiles.

This specimen is a mere 60 centimetres in length, but as it is the only known example and the reptile’s age at death is unknown, it is impossible to say whether the species grew larger, says Spiekman.

However, he is confident that it was unlikely to have reached the size of its very long relative Dinocephalosaurus, the “Chinese sea dragon”, which could easily grow to over 4 metres.

“This was certainly a good and agile swimmer, mainly using its tail for swimming, its long front flippers for steering and its long neck to catch fish,” says Spiekman. “AłÜ˛őłŮ°ů´Ç˛Ô˛ą˛µ˛ą probably would have looked a little like a lizard or a croc trying to be a seal or an otter and likely would have had scaly skin, for example.”

The fossil shows that the basic plan of the reptilian digestive tract has changed little in 245 million years, he says, and the “straight and simple intestines is what we see in most modern predatory reptiles, including those eating fish”.

Although the fossil is of high quality, the internal organs of Austronaga are only preserved in two dimensions. This is unlike those of a 380-million-year-old fossil of an armoured fish that Long and his colleagues , which is regarded as having the oldest known organs of any vertebrate.

“But this is still an incredibly well-preserved fossil,” he says.

The asteroid strike 66 million years ago caused a planetary-scale firestorm that burned dinosaurs to a crisp all over the world, according to simulations of the impact.

The so-called Chicxulub asteroid, which was 10 to 15 kilometres wide, landed in what is today the Gulf of Mexico at the end of the Cretaceous Period.

Until now, it has been thought that most of the worst effects of heat and fires would have been relatively regional, and global extinctions were mainly caused by a “nuclear winter”, where dust blocks out the sun causes dramatic cooling.

at Purdue University, Indiana, and his colleagues analysed geological observations and impact simulations in the laboratory, which showed around five times more material was vaporised by the strike than previously thought.

The new work suggests that in the aftermath of the impact, a plume of rock vapour was blasted tens of thousands of kilometres into space and ended up being distributed high above the entirety of the planet.

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“After the impactor first strikes the Earth, it only takes about a second for much of the kinetic energy to be converted to heat, vaporising over 1000 cubic kilometres of rock,” says Johnson. 

Just seconds later, the vapour plume expanded above much of Earth’s atmosphere into space, he says, leading to both dust and glassy, metallic beads called spherules, condensing from the vapour.

This immense vapour cloud ultimately turned into 1.6 trillion tonnes of dust, which blanketed the planet, sealing in heat, the study found. Meanwhile, the heavier spherules slammed back into the atmosphere.

“As this material re-enters the atmosphere over the coming hours, friction decelerates and heats the spherules, creating an approximately hour-long pulse of thermal radiation,” says Johnson.

“This would kill off creatures that were unable to shelter from it and was intense enough to ignite forest litter like grass and pine needles and may have even been enough to ignite trees.”

The geologic record suggests the ensuing fires may have lasted for years and would have been reminiscent of the bushfires currently gripping Europe, except on a global scale, he says.

“The Cretaceous animals would have received 17 times the dose of thermal radiation that is 100 per cent lethal to humans,” says Johnson. “That should be enough to kill off even thick-skinned dinosaurs.”

at the Queensland University of Technology in Australia says the study shows that the dust layer encircling the planet was essentially opaque to infrared and visible light, trapping the heat.

“Every joule of heat created by incoming spherules is turned into a thermal pulse that bakes the surface of the Earth,” says O’Neill. “For about 30 minutes, the land is turned into history’s largest barbecue.”

However, this isn’t the whole story, he says. For example, life in the oceans was also badly affected by the event, driving many marine animals such as mosasaurs and ammonites extinct. This is better explained by the effects of a nuclear winter blocking out the sun on photosynthesising organisms, rather than an atmospheric thermal pulse, says O’Neill.  

“We tend to think of mass extinction events as a murder mystery – if we can just find the murder weapon, we could solve the case. But mass extinctions seem more like a cascading system of failures,” he says.

A parasitic fungus that grows on caterpillars has been turned into a dress designed to be able to repair itself if damaged.

In the video game and TV series The Last of Us, Cordyceps fungi evolve to infect humans and turn them into zombies, but in reality they are harmless to humans.

Using the fungus Cordyceps militaris as a base, at the Chinese Academy of Sciences and her colleagues created a living textile that can be “programmed” with different properties using various microbial components.

It feels denser and less fibrous than cotton, says Li, and is closer to a soft, non-woven sheet or a flexible leather-like material.

“After washing and processing, the material does not have a strong mushroom-like smell,” she says. “A slight biological or fermentation-related odour may be detectable in freshly prepared samples, but this can be greatly reduced through cleaning, drying and post-treatment.”

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The fungus is made up of thin filaments known as hyphae. Li and her colleagues first grew the fungus as small, spherical pellets in liquid culture, then washed them and placed them into moulds where they formed a sheet.

To prevent the resulting textile from becoming brittle, it was soaked in glycerol, which acts as a “plasticiser”, making the naturally rigid fungal structure softer and more flexible.

“We do not use a conventional fabric, polymer mesh or other external supporting scaffold,” says Li. “The Cordyceps militaris mycelial pellets themselves serve as the structural building blocks, and their intertwined hyphae form a continuous, self-supporting sheet.”

To add colour to the material, the team introduced yeast cells that were engineered to produce orange, blue and purple pigments. “These cells can be applied to the fungal textile so that the colour is generated biologically, rather than through conventional synthetic dyes,” says Li.

The researchers also showed they could change the properties of the textile by adding other fungi, for example making it clean itself by repelling water droplets. For UV protection, they added Aspergillus niger, a mould that commonly grows on fruit and vegetables. This forms a dark layer on the surface of the material containing melanin pigment, which absorbs ultraviolet radiation.

If the textile is damaged, then fresh, wet fungal pellets can be applied to the area that needs repair and the fungus simply grows over the breach.

Under dry conditions, most biological activity is greatly reduced, and the cells may remain inactive or dormant, says Li.

But under humid conditions with nutrients present, some cells can become active again. This latent biological capacity is what enables functions such as regrowth and repair, and also means that the material is readily biodegradable, showing near-complete visible degradation in soil after just over 40 days.

Li and her colleagues created a dress out of their fungal material, but so far no one has worn it. “We’ve treated it as a rather precious display piece, and it was made in a small size,” she says. “Perhaps next time we should find a few petite and adventurous volunteers to try it on and see how it looks in motion.”

at the University of Sydney, Australia, says the biodegradability of the dress is amazing compared with what we currently have in terms of getting rid of waste from fast fashion.

But that is also a drawback because you don’t really want to be wearing something that is too easily biodegradable, as “it’ll break down while you’re wearing it”, he says.

As the textile is alive, Beardsley envisages one day being able to change its qualities in real time. “If there was some way that you can make it water-repellent for a while, becoming less breathable during rain, that would be fantastic, and then you can revert to the more breathable, less water-repellent version afterward,” he says.

Climate and health activist has been immortalised in a sculpture, The Solomon Siren – recently installed on her now-flooded former home: Kale Island in the Solomon Islands.

Rising tides completely flooded the 50,000-square-metre Pacific island in 2016. The sculpture sits in the intertidal zone, where patches of rubble and sand rise above the ocean surface from time to time.

Sculptor Jason deCaires Taylor made the sculpture as part of his Sirens series of installations around the world highlighting warming seas, sewage pollution and the presence of microplastics.

When flooding made life untenable, Bartlett and her family had to evacuate to one of the main islands. “Back then, [the island] was land – green, vibrant, full of life,” says Bartlett in a film accompanying the sculpture’s installation. “Kale became one of the first documented islands in the Solomons lost to sea level rise.”

The sculpture consists of a marine-grade stainless steel tree on which a life-sized figure of Bartlett leans. The artwork also uses biochar and pH-neutral cement. Hauntingly, as the tide rises and falls, it is intermittently hidden as waves roll over.

Incorporated into the sculpture are inscriptions recording past milestones of Kale’s submergence along with predictions for a sea level rise of up to 20 centimetres by 2046. But as Taylor says, the sculpture isn’t intended to work as a scientific measuring instrument, but as a “symbolic representation” of a changing relationship between land and sea.

“What happened is a warning not only for us, but for the world,” says Bartlett.

The discovery of layers of grass ash stretching back 25,000 years suggests that a cave in south-eastern Australia was home to elaborate rituals for over 1000 generations of Indigenous inhabitants.

Cloggs cave is in the homeland of the GunaiKurnai people in south-eastern Victoria. In 2024, archaeologists and traditional owners announced the discovery of ancient artefacts inside the cave, providing evidence for the extraordinary possibility that a ritual had survived for 12,000 years through to modern times.

Now, at Monash University in Melbourne, along with , a GunaiKurnai elder, and their colleagues have uncovered evidence that more than doubles the amount of time that cultural practices took place in the cave. The purposes of these rituals are thought to have included magic, healing and cursing.

The team found thousands of microscopic, silt-sized preserved cells called phytoliths that form when plants absorb soluble silica from the soil and deposit it within their structures. Grasses were the dominant vegetation type, making up 97 per cent of the burnt phytoliths found in the cave.

David thinks this is because grasses immediately turn to ash, rather than charcoal, when burnt, and the ash was considered important for rituals.

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These phytolith fossils indicate that people had brought whole grasses, including their roots, into the cave and burnt them to repeatedly make thin layers of ash, he says.

The researchers were then able to link this practice of burning ashes with cultural practices described by the Alfred Howitt. In the 1880s, in other parts of GunaiKurnai country Howitt recorded the rituals of powerful medicine men and women that he described as “wizards”. His accounts show that ash was an important part of GunaiKurnai rituals in the 19th century.

“Such burning of grass goes back to 25,000 years ago inside the cave, but between 4400 and 1600 years ago, the burning of ash layers became more frequent and more widespread across the floor of the cave,” says David.

Around 2000 years ago, a standing stone was erected in the cave and over the next 400 years, grass was burnt all around it.

Unlike pollen, which can be transported by wind, phytoliths are usually deposited immediately beside the plants from which they originate. The team also ruled out the possibility that the fossils were washed in by a flood.

The cave also contained phytoliths deposited in the scats of common brushtail possums (Trichosurus vulpecula), but these were unburnt, distinguishing them from the phytoliths created by human activities.

The ashes weren’t always associated with the same kinds of archaeological remains, suggesting they were created by a range of practices in the cave, says David.

“The common theme here is that people repeatedly piled grasses and burnt them,” he says. “Prior to 4400 years ago, the bringing and burning of grass into the cave was more sporadic and less frequent, not resulting in the repeated dense ashy layers that we see after 4400 years ago, although other kinds of ritual activities involving stalactites and miniature fires with single fat-smeared sticks were performed during those earlier times.”

at the Australian National University in Canberra says archaeobotanical research has been underrepresented in Australian archaeology, which has meant that a “large portion of past life has been understudied”.

“This is a great study, weaving careful scientific analysis of phytoliths with GunaiKurnai cultural knowledge to show that grasses were specially collected and burnt at Cloggs cave to support ritual practices over many millennia,” says Florin.

Hunter-gatherers transported brown trout into the mountains of Norway at least 7000 years ago so they could be harvested during summer foraging trips into the highlands.

That is the only possible explanation for how fish could have populated isolated mountain lakes that had been covered by a kilometres-thick ice sheet for tens of thousands of years, says at the University of Oslo, Norway.

“This is the oldest documented example of human-mediated translocation of fish in the world,” says Mjærum.

Until around 8400 years ago, Lake Tesse, at an elevation of around 850 metres, was covered by the Fennoscandian ice sheet, leaving an ecological blank canvas once it retreated.

Yet before it was transformed for hydropower storage in the 1940s, Lake Tesse was regarded as one of the richest brown trout waterways in Norway, yielding 9 tonnes of the fish annually.

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While it has long been suspected that humans had a hand in establishing the brown trout population in Lake Tesse, we had no idea how long ago this happened.

Alternative ideas have included transportation by birds or natural migration of fish and eggs upstream. But most Norwegian mountain lakes, including Lake Tesse, only had brown trout until recently, and geographical features such as large waterfalls make natural dispersal upstream impossible.

Mjærum and his colleagues studied the partially buried remains of elaborate wooden fish traps, discovered in 2022 when the lake level was lowered.

Radiocarbon dating showed that the oldest trap dated from around 4950 BC. By correlating the recovered wood with the pine tree ring chronology available for the central Scandinavian mountains, the team was also able to precisely date some of the posts that were part of the younger traps.

One came from a tree felled between spring 2669 BC and winter 2669-2668 BC, and another 12 years later during the winter of 2657-2656 BC, demonstrating that the traps must have been maintained to keep them in good working order.

“Therefore, it is possible that this form of trap fishing was ongoing in Tesse during much of the period between 5000 and 2650 BC,” says Mjærum.

The transport of fish into the lakes is an early example of people managing the environment to provide food, centuries before the advent of farming in Scandinavia. There is evidence that fish farming began even earlier in other parts of the world,

How people transported the fish is unknown, but they may have used waterskins. People probably stayed in the mountains for part of the summer season, hunting reindeer and fishing, but spent the winters in the valleys or along the coast where the climate was milder, says Mjærum.

“A good and predictable food supply also made longer stays possible, not only for hunters aiming for big game, but for whole family groups,” he says.