These frightening ogre-faced spiders use their legs to ‘hear’

Ogre-faced spiders might be an arachnophobe’s worst nightmare. The enormous eyes that give them their name allow them to see 2000 times better than we can at night. And these creepy crawlers are lightning-fast predators, snatching prey in a fraction of a second with mini, mobile nets. Now, new research suggests these arachnids use their legs not only to scuttle around, but also to hear.

In light of their excellent eyesight, this auditory skill “is a surprise,” says George Uetz, who studies the behavioral ecology of spiders at the University of Cincinnati and wasn’t involved in the new research.

Spiders don’t have ears—generally a prerequisite for hearing. So, despite the vibration-sensing hairs and receptors on most arachnids’ legs, scientists long thought spiders couldn’t hear sound as it traveled through the air, but instead felt vibrations through surfaces. The first clue they might be wrong was a 2016 study that found that a species of jumping spider can sense vibrations in the air from sound waves.

Enter the ogre-faced spider. Rather than build a web and wait for their prey, these fearsome hunters “take a much more active role,” says Jay Stafstrom, a sensory ecologist at Cornell University. The palm-size spiders hang upside down from small plants on a silk line and create a miniweb across their four front legs, which they use as a net to catch their next meal. The spiders either lunge at bugs wandering below or flip backward to ensnare flying insects’ midair.

To determine how much this agility relied on eyesight, Stafstrom placed a tiny blindfold over the spiders’ eyes. Although they could not capture bugs on the ground, they could still catch a meal midflight, he and colleagues reported in 2016.

To find out how they did it, the researchers devised a new study: First, they inserted tiny electrodes in spider legs that had been removed to determine whether the vibration-sensing receptors on their limbs could detect sound. Next, they implanted electrodes into the brains of other spiders—who got to keep all their legs—to see whether they processed sound. Finally, they placed the spiders (and legs) in a booth that eliminated all vibrations from below and played different sounds from 2 meters away. They found that both the legs and living spiders responded to a broad range of frequencies, from the low rumble of 100 hertz (as might be made by a passing truck) to the high-pitched whine of 10,000 hertz, the researchers report today in Current Biology.

The researchers then played the five sounds that received the strongest responses to 25 spiders in the wild and 51 in the lab. When the team played tones at frequencies of 150, 400, and 750 hertz—which are similar to sounds of wing beats from moths, flies, and mosquitoes—more than half of the spiders started to do backflips as if to hunt, Stafstrom says.

But the spiders remained still during higher frequency tones of 2300 and 4400 hertz. Stafstrom guesses that’s because these higher pitched tones fall in the range of sound made by chirping birds, which can munch on the spiders. But Uetz is unconvinced: The spiders are active at night, unlike many avian predators. The spiders could be attuned to other nocturnal predators, he points out.

Now, Stafstrom wants to see whether the spiders can tell where sounds are coming from. “You don’t want to miss a meal, and you want to be fairly accurate,” he says. If these spiders use directional hearing, as he suspects, that could help explain the speed of their aerial strikes, he adds.

Because all spiders have these vibration-sensitive receptors in their legs, the findings raise the question of how common hearing is among them, Uetz says. Compared with other animals, “we don’t know diddly about spiders,” he says. “They are much more complex than people ever thought they were.”

Jury duty for global warming: citizen groups help solve the puzzle of climate action

The 110 members of the U.K. Climate Assembly were randomly selected.


Until recently, Sue Peachey, an apartment building manager in Bath, U.K., didn’t think much about climate change. “I did my recycling,” she says. “I just wasn’t aware of how serious it was.” She never imagined the U.K. Parliament asking for her advice on climate policy. But last year, a letter arrived in her mailbox inviting her to do just that, by joining the United Kingdom’s first ever climate assembly. “I’d never done jury service—I’d never done anything like it before,” Peachey says. She thought about her stepchildren and stepgrandchildren, and the legacy they would inherit. “That was the main reason why I thought, ‘Well, if somebody is going to have input on it, why shouldn’t it be me?’”

So, Peachey signed up to spend four weekends driving to Birmingham to listen to experts, deliberate with 109 fellow citizens, and recommend climate policies. The assembly was more than a focus group or a town hall meeting: It was an experiment in handing political power to a random but representative set of citizens. Last month, it produced its final report, and its recommendations will shape debates in Parliament.

The U.K. Climate Assembly is one of a growing number of similar gatherings popping up across Europe, many of them charged with addressing climate change and other science-heavy issues. A citizens’ assembly in Ireland that deliberated from 2016 to 2018 led to a referendum that legalized abortion and a government plan to quadruple its carbon tax by 2030. This year in France, an assembly made 149 climate policy recommendations, and President Emmanuel Macron has agreed to push for 146 of them, including making “ecocide” a crime and including climate goals in the French constitution. Spain, Denmark, and Scotland have announced their own upcoming climate assemblies, although they have been delayed by the coronavirus pandemic. And at the regional and local level, dozens of citizens’ juries and councils have drawn up policies on climate adaptation, air quality, and environmental protection.

Advocates say these carefully designed “minipublics” can break political stalemates by bringing together citizens to hear evidence and deliberate. They point to evidence of high-quality policy created by fresh and diverse perspectives, and to behavioral research showing the power of guided deliberation to change minds and reduce polarization. What began as an abstract, academic model has taken off in real-world settings, says David Van Reybrouck, a Belgian historian, author, and advocate of minipublics. “We’ve really seen a wave, a surge, of deliberative democracy.”

Claudia Chwalisz, a policy analyst who has tracked the growing wave of minipublics for the Organisation for Economic Co-operation and Development, a club of economically developed nations, says these deliberative bodies are well-suited to tackling long-term issues because citizens need not worry about the short-term incentives of electoral cycles, giving them more freedom than elected politicians. A minipublic can also embody a wide range of perspectives, an advantage for problems with complex trade-offs and value-based dilemmas. Climate policy, she adds, ticks both boxes.

Deliberative surge

The number of national and local minipublics—randomly selected assemblies that deliberate over policy recommendations—has risen in the past decade. Many dealt with scientific questions.

199510020304020002005201020152019*Number per yearOther policyScience policy*** The Organisation for Economic Co-operation and Development tallied minipublics through November 2019; Science assembled data for the rest of 2019.** Dealt with questions on climate, environment, health, biotechnology,neuroscience, research priorities, or food technology.


Letting ordinary people determine climate policy might seem risky, but “if climate scientists have learned anything over the last couple of decades, it’s that they can’t just do the science and expect it to speak for itself,” says John Dryzek, a political scientist at the University of Canberra who wants to use the approach to tackle another fraught science issue. Last month, he and other minipublic advocates published a call for what would be the first global citizens’ assembly. He wants it to take on the issue of genome editing, on the grounds that its widespread ramifications demand international agreements. For this and many other science policy questions, he argues, minipublics are an excellent way to integrate public values with advice from scientists and ethicists. “Scientists don’t have a monopoly on public values,” he says.

Randomly assigning citizens to positions of political power has a history stretching back to ancient Greece, where the Athenians used the practice to select magistrates and members of their representative Council of Five Hundred. But the architects of electoral systems in postrevolution France and the United States preferred a republican system of professional politicians—an “elected aristocracy”—over outright rule by the masses, Van Reybrouck says. “They were as much afraid of democracy then as we would be of anarchy today.”

Now, however, electoral democracies are floundering in the face of partisanship and populism. In November 2018, Van Reybrouck attended a lunch during a French state visit to Belgium and was pulled into a conversation with Macron. At the time, France was on fire: Thousands of protesters furious at the prospect of a fuel tax hike were expressing their rage in the streets. “What did they want me to do?” Van Reybrouck recalls Macron asking in frustration. “They want me to save the environment and at the same time to keep petrol prices low.”

Bringing citizens into the discussion would help, Van Reybrouck says he told the French president. Not everyone in France has access to public transit, and those already struggling with the costs of a car would now be further disadvantaged. When Van Reybrouck started to talk about minipublics, he says, “[Macron] puts down his fork and takes a ballpoint and starts taking notes.”

The next month, Macron’s administration walked back the tax hike and announced a series of public town hall meetings for citizens to air grievances. In April 2019, Macron announced the Citizens’ Convention on Climate. Among the assembly’s many eventual proposals were a fuel tax for recreational aviation, an insurance tax based on vehicle emissions, and a tax on vehicle weight—but no fuel tax for drivers.

Macron’s situation was hardly unique. Governments are hamstrung by the problem of climate action, says Rebecca Willis, an environmental social scientist at Lancaster University who helped choose expert speakers for the U.K. Climate Assembly. She interviewed U.K. politicians and studied their speeches and found that they underestimated public support for climate action. “They didn’t feel under any pressure to act,” she says. Politicians also tend to overestimate the opposition of a vocal minority to some climate measures—such as onshore wind farms, she says. And they fear punishment at the ballot box, where citizens express their opinions about a multitude of policies at the same time: “Voting is such a blunt instrument.”

In mid-2019, the United Kingdom set a target of net zero carbon emissions by 2050, a first step toward keeping its commitments to the 2016 Paris agreement. But since then, there’s been no action to meet the goal, says Darren Jones, a Labour Party politician. “We’ve legislated this target, and that’s great,” he says. “But now how are we going to get there?” Climate policies need the backing of the public, Willis says, which means the public should be involved in creating them. And so, like Macron, Jones and other members of the U.K. Parliament asked the public to help.

The U.K. Climate Assembly deliberated in Birmingham, after hearing from climate scientists and advocacy groups.


Peachey was one of the 30,000 people whose postcode came up in a random lottery to choose potential participants, and one of 1748 people who responded to the invitation. An algorithm whittled the sample down to 110 people who matched the overall U.K. population’s gender, age, ethnicity, education level, geographic region—and, crucially, their degree of concern about climate change. This two-stage process limits the influence of self-selection, which skews toward people who already have strong interests in a topic and drives polarization, says Stephen Elstub, a political scientist at Newcastle University who is studying how well the U.K. Climate Assembly worked.

The nonprofit Involve, contracted by Parliament to run the assembly, tried to eliminate barriers to entry, says Sarah Allan, Involve’s head of engagement. The team chose Birmingham as a geographically central city and arranged travel, accommodation, child care, and accessibility adaptations like large-print reading materials. They covered all the members’ costs, paying upfront when necessary so as not to exclude members who couldn’t pay out of pocket. And they paid all members an honorarium of £150 for each weekend, a lure to those with little preexisting interest in the subject. “It’s really important to try and get the people who wouldn’t normally participate,” Elstub says.

On a gloomy Friday evening in late January, the assembly members gathered for the first time on the top floor of the glossy, high-rise Park Regis hotel. Famed naturalist David Attenborough made an appearance to greet the members and host a Q&A about his work. In the first sessions, U.K. academics explained climate science basics: the greenhouse effect, the impacts of rising temperatures. Peachey’s understanding skyrocketed. “I just thought it was getting hotter, but that’d be nice,” she says. “I bet you there’s a lot of people out there who think the same thing.”

Over three weekends—and a fourth weekend forced online and stretched over three weekends because of the pandemic—the assembly listened not only to scientists, but also to representatives of interest groups such as Greenpeace and industry body Energy UK. The goal was to provide both impartial information and explicitly labeled opinions from advocates, says Chris Stark, chief executive of the Committee on Climate Change, an independent body advising the government. Assembly member Ibrahim Wali, a doctor from Epsom, says that although some members didn’t believe the scientists or think climate action was worthwhile, it was clear to everyone that they were not there “to argue about whether climate change is real.” The assembly’s clear task—identifying policies to reach net zero by 2050—kept discussions on track, he adds.

Sessions shifted between speaker presentations and small group discussions, where members deliberated on policy recommendations, then voted on them by secret ballot. The ballot papers combined predetermined policy suggestions—like a ban on the sale of petrol, diesel, and hybrid cars by 2035—with ideas and amendments suggested by members.

With facilitators making space for everyone to chime in, Wali says no one dominated in the small group discussions. A poll of members found that 94% felt their views were respected, even when others disagreed, and 95% felt they were given “ample opportunity” to express their views. In an age of polarization, a willingness to respectfully hear other views, and the reasons people hold them, changes the hostile dynamic of politics entirely, says Alice Siu, a political scientist at Stanford University: “Something magical happens.”

Some researchers contend that entrusting policymaking to ordinary citizens is risky. Cass Sunstein, a legal scholar at Harvard Law School, has argued that deliberating groups can be fertile ground for polarization, pointing to evidence from experiments showing that groups such as churchgoers or jury members can spiral into polarized conclusions.

But a long tradition of research suggests the discussions are often constructive. In 1994, Stanford political scientist James Fishkin polled 869 people—randomly selected from the U.K. electoral register—on their attitudes toward rising levels of crime, asking questions such as whether more people should be sent to prison and whether sentences should be tougher. Next, 301 of them agreed to meet for 2 days in Manchester, where they heard from politicians, lawyers, and police. They asked questions and discussed policy proposals in small groups before being polled again. The results showed participants had changed their opinions, in some cases dramatically: For each question in the poll, at least one-third of the deliberators had shifted their stance to some degree, and on some questions, as many as two-thirds had changed their minds.

An Extinction Rebellion climate protest in London in September. Social scientists have found that politicians underestimate public support for climate action.


Fishkin and his collaborators around the world went on to conduct more than 100 of these experiments, which they call deliberative polls. They have explored opinions on flood management in Uganda, constitutional reform in Mongolia, and educational reform in Northern Ireland. A deliberative poll held in Dallas last year saw Republicans and Democrats moving toward a middle ground on divisive issues such as refugee resettlement and a minimum wage. Across the board, the researchers found participants could back up their opinions with clear reasoning. Siu, analyzing transcripts from these experiments, has found that men and women contributed equally to discussions, contrary to expectations that men would dominate.

Such good outcomes aren’t guaranteed, says Sander van der Linden, a University of Cambridge social psychologist who studies decision-making. In some cases participants do become more polarized, rather than less, in the face of disagreement; that happened in group discussions of gay rights in Poland—not one of Fishkin’s experiments—that had recruited participants from pools with strong opinions. And in groups with a majority and minority opinion, “polarization cascades” can override the minority, causing them to shift their opinion for reasons that have nothing to do with evidence and good arguments.

But with high-quality information, facilitators to keep discussions on track, and rules to enforce civility, it is possible to steer people away from group biases, van der Linden says. In 2017, Kim Strandberg, a behavioral scientist at Åbo Akademi University in Finland, and his colleagues found such measures prevented polarization in discussions about the status of the Swedish language, spoken by a minority in Finland. “The people who are polarized and tribal are actually a minority,” Dryzek says. A good assembly may include some members of this minority, he says. “But most of the people in a minipublic have no history of activism or involvement with an issue, and so they’re in a good position to reflect on what they hear.”

What makes deliberation so powerful and positive seeming is still a bit of a black box, says André Bächtiger, a political scientist at the University of Stuttgart. Recent experiments like Strandberg’s seem to demonstrate the effects of deliberation and good design. But a deliberative experience is made up of countless moving parts of human interaction, and “we just don’t have everything under control,” Bächtiger says. “We’re still in the infancy of all of this.”

And the growing popularity of minipublics carries another risk: Some will be constituted as cheap imitations, without the crucial design elements. Fishkin trademarked the term “deliberative poll” partly to maintain quality control, and Chwalisz and her colleagues have published guidance on best practices. But citizens’ panels, juries, and conferences that rely on self-selected participants still spring up. “Lots of people are calling a lot of different things citizens’ assemblies now, because it’s kind of a trendy method,” says Graham Smith, a political scientist at the University of Westminster.

The U.K. Climate Assembly’s final report, published on 10 September, says climate action should be based on cross-party leadership and principles of fairness to different groups of people. Its policy recommendations, supported by a majority of assembly members, include restoring public ownership for public transit—largely privatized in the United Kingdom—introducing air travel taxes that increase as people fly more often, and adding labeling to food that indicates its carbon footprint.

Will those recommendations be adopted in the end? Whereas the French assembly was set up by Macron himself, the U.K. assembly was run at arm’s length from Prime Minister Boris Johnson’s Conservative government, which means its impact will be less direct, Smith says. The parliamentary committees that established it will use the report to introduce debates, inform their own recommendations, and scrutinize legislation coming from Johnson and his government, but “we’ve yet to see how the government will respond,” Smith says.

Even if a minipublic’s recommendations are discussed by politicians, it’s difficult to say how much they influence later policies, says Émilien Paulis, a political scientist at the French-speaking Free University of Brussels . But in an analysis of data on the policy impact of 55 minipublics, Chwalisz and her colleagues found that, 75% of the time, public authorities implemented more than half the citizens’ suggestions. Only six minipublics in the sample saw none of their recommendations implemented.

Some advocates have suggested imbuing minipublics with official legislative powers, but that would be antidemocratic because they were never given consent to govern, says Cristina Lafont, a political philosopher at Northwestern University who describes herself as a “frenemy” of the deliberative bodies. Keeping minipublics in an advisory role, rather than enabling them to produce binding recommendations, is more truly democratic, she says. Although she wants the public to engage in thoughtful deliberation, she worries that minipublic participants cannot be held to account by the wider public. And being too enthralled by the results of “lottocratic” minipublics runs the risk of encouraging a lazy shortcut to good governance, she says: “Why not let the minipublics do the thinking and the deciding for us?”

Dryzek agrees that democracies should not blindly defer to the decisions of minipublics. But they still offer a critical piece of information for policymakers that experts can’t provide, he argues: a meaningful gauge of public values.

For Peachey, the climate assembly made the right course clear. Her new awareness of climate change and its impacts has galvanized her on behalf of her stepgrandchildren. “We’re not going to benefit,” she says. “But future generations will.” Since the U.K. assembly’s final meeting, Peachey has joined her local parish council and worked with fellow councilors to declare a climate emergency—a symbolic gesture that has led to local climate minipublics elsewhere in the country. She daydreams about bringing a wind farm to an old military airfield near Bath.

Her own habits have changed, too. She now shops at her local farmer’s market and plans to get solar panels for her home. Her new electric car is a great conversation starter, a chance for her to unpack what she learned at the assembly, she says. “I’ve been given this information. It seems a shame not to use it.”

How dogs tracked their humans across the ancient world

Libyan rock art that may date back 7000 years depicts a hunter and his dog.

Joe and Clair Carnegie/Libyan Soup/Getty Images

Sometime toward the end of the last ice age, a gray wolf gingerly approached a human encampment. Those first tentative steps set his species on the path to a dramatic transformation: By at least 15,000 years ago, those wolves had become dogs, and neither they nor their human companions would ever be the same. But just how this relationship evolved over the ensuing millennia has been a mystery. Now, in the most comprehensive comparison yet of ancient dog and human DNA, scientists are starting to fill in some of the blanks, revealing where dogs and humans traveled together—and where they may have parted ways.

“It’s a really cool study,” says Wolfgang Haak, an archaeogeneticist at the Max Planck Institute for the Science of Human History. “We’re finally starting to see how the dog story and the human story match up.”

Dogs are one of the biggest enigmas of domestication. Despite decades of study, scientists still haven’t figured out when or where they arose, much less how or why it happened. A 2016 study concluded that dogs may have been domesticated twice, once in Asia and once in Europe or the Near East, but critics said there wasn’t enough evidence to be sure. A few years later, researchers reported signs of dogs in the Americas as early as 10,000 years ago, yet those canines appear to have vanished without a genetic trace. Other studies have found evidence of ancient dogs in Siberia and elsewhere, but scientists don’t know how they got there or how they’re related.

To fill in some of the blanks, two big names in dog and human genetics teamed up: Greger Larson, an evolutionary biologist at the University of Oxford, and Pontus Skoglund, a paleogenomicist at the Francis Crick Institute. Larsen, Skoglund, and colleagues sifted through more than 2000 sets of ancient dog remains dating back nearly 11,000 years from Europe, Siberia, and the Near East. In the process, they added 27 ancient dog genomes to the five already on record. They then compared those with the genomes of 17 humans living in the same places and times as the dogs.

The dog DNA alone revealed some surprises. As early as 11,000 years ago, there were already five distinct dog lineages; these gave rise to canines in the Near East, northern Europe, Siberia, New Guinea, and the Americas, the team reports today in Science. Because dogs had already diversified so much by that time, “domestication had to occur long before then,” Skoglund says. That fits with archaeological evidence: The oldest definitive dog remains come from Germany about 15,000 to 16,000 years ago.

Remarkably, pieces of these ancient lineages are still present in today’s pooches. Chihuahuas can trace some of their ancestry to early American dogs, for example, whereas Huskies sport genetic signatures of ancient Siberian dogs, the team found. “If you see a bunch of different dogs in a dog park,” Skoglund says, “they may all have different ancestries that trace all the way back 11,000 years” (see figure below).

Today’s dogs can trace their ancestry to canines that lived up to 11,000 years ago.

Bergstrom et al., Science (2020)

When the researchers compared their dog DNA with modern and ancient wolf DNA, they got another surprise. Most domesticated animals pick up genetic material from their wild relatives—even after domestication—because the two species often live in close proximity and can still mate (think pigs and wild boars). But dogs show no such “gene flow” from wolves. Instead, the wolves gained new DNA from the dogs—a one-way street.

Larson chalks this up to the intimate relationship between dogs and humans. If your pig or chicken becomes a bit wilder thanks to an infusion of feral DNA, it doesn’t matter, because you’re going to eat them anyway, he explains. But dogs that go native make bad guards, hunting companions, and friends. “If you’re a dog and you have a bit of wolf in you, that’s terrible,” Larson says. People will “get rid of the dog.”

The wolf-dog analysis also suggests dogs evolved only once, from a now-extinct wolf population. Still, Larson, who led the 2016 study on multiple domestication events, says more data are needed to seal the deal.

Then the scientists brought humans into the mix. They selected human DNA samples from the same places and eras for which they had ancient canine DNA, and traced the genetic history of each. “It’s like you have an ancient text in two different languages, and you’re looking to see how both languages have changed over time,” Skoglund says.

In many places, the team found a strong overlap between human and dog genomes. For example, farmers and their pups in Sweden about 5000 years ago both trace their ancestry to the Near East. This suggests early farmers took their dogs with them as agriculture spread throughout the continent. “Writ large, as humans moved, they moved with their dogs,” Larson says.

But sometimes the stories didn’t match up. Farmers in Germany about 7000 years ago also came from the Near East and also lived with dogs. But those animals seem more similar to hunter-gatherer pups, which came from Siberia and Europe.

That suggests many early migrants adopted local dogs that were better adapted to their new environment, Haak says. The benefits were many, adds Peter Savolainen, a geneticist at the Royal Institute of Technology and an expert on dog origins. “They were cute. You could use them. You could even eat them.”

Savolainen calls the study “very thorough,” and adds it’s “fantastic” that the researchers were able to bring together so many data. But he has long argued that dogs arose in Southeast Asia and says the work is incomplete without samples from that corner of the globe. “Without those, you could be missing an important part of the picture.”

For now, Larson says his team is analyzing “a ton” of wolf and dog genomes. He and his colleagues have also begun to look at ancient skull shape and genetic markers that could give clues to what early dogs looked like. Whatever he finds, he’s counting on being surprised. “We have to expect the unexpected,” he says, “because that’s all ancient DNA ever gives us.” 

DNA tracks mysterious Denisovans to Chinese cave, just before modern humans arrived nearby

For today’s Buddhist monks, Baishiya Karst Cave, 3200 meters high on the Tibetan Plateau, is holy. For ancient Denisovans, extinct hominins known only from DNA, teeth, and bits of bone found in another cave 2800 kilometers away in Siberia, it was a home. Last year, researchers proposed that a jawbone found long ago in the Tibetan cave was Denisovan, based on its ancient proteins. But archaeologist Dongju Zhang of Lanzhou University and her team wanted more definitive evidence, including DNA, the molecular gold standard. So in December 2018, they began to dig, after promising the monks they would excavate only at night and in winter to avoid disturbing worshippers.

After working from dusk to dawn while temperatures outside plunged to –18°C, then covering traces of their dig every morning, the scientists’ persistence paid off. Today in Science, Zhang’s team reports the first Denisovan ancient DNA found outside Denisova Cave: mitochondrial DNA (mtDNA) gleaned not from fossils, but from the cave sediments themselves. Precise dates show the Denisovans took shelter in the cave 100,000 years and 60,000 years ago, and possibly as recently as 45,000 years ago, when modern humans were flowing into eastern Asia.

The find shows that even though their bones are rare, “Denisovans were widespread in this hemisphere,” says University of Oxford geochronologist Tom Higham, who was not part of the study. It also ends a long quest for Denisovan DNA outside Siberia. “Every year, I’ve said we will find this,” says co-author Svante Pääbo of the Max Planck Institute for Evolutionary Anthropology (EVA). “It’s been a decade.”

The presence of Denisovan DNA in the genomes of living people across Asia suggested these ancient humans were widespread. But the partial jaw from Baishiya Karst Cave was the first fossil evidence. Zhang and her colleagues identified the jaw as Denisovan based on a new method that relies on variation in a protein. Some researchers questioned the claim, however, because the method was new, and no one knew where in the cave the jaw had been found.

Archaeologists wearing anticontamination gear sampled Baishiya Karst Cave on a winter night.


Those questions are likely to fade. The dig, led by Zhang and Fahu Chen of the Institute of Tibetan Plateau Research, took many sediment samples and found charcoal from fires, 1310 simple stone tools, and 579 pieces of bone from animals including rhinos and hyenas. Paleogeneticist Qiaomei Fu of the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing managed to extract hominin mtDNA from the sediment itself. The mtDNA, perhaps shed in poop or urine, most closely matched that of Denisovans.

Meanwhile, geochronologists led by Bo Li and Zenobia Jacobs of the University of Wollongong dated material from those same sediment samples. They used optical dating to reveal when light last struck mineral grains in the samples, showing when each grain was buried. The four layers that yielded Denisovan mtDNA were laid down 100,000, 60,000, and as recently as 45,000 years ago, although the younger sediments were disturbed.

The dates for the older sediments seem highly reliable, says Higham, who dated Denisova Cave. And by showing DNA and dates can be gleaned from the same sediment samples, the work opens “a new era of molecular caving,” says geochronologist Katerina Douka of the Max Planck Institute for the Science of Human History.

The charcoal in the cave shows its occupants built fires. They also used simple stone tools, and, from the cave’s high opening, must have spied on animals grazing in the meadows below. Some may also have been on the lookout for modern humans, who were in the region by 40,000 years ago.

In a separate study published today in Science, Pääbo reports extracting modern human DNA, the oldest yet in Asia, from 34,000- and 40,000-year-old fossils from what is now Mongolia and from near Beijing, respectively. Those genomes included Denisovan DNA, the legacy of mating that happened roughly 50,000 years ago. But the Denisovan sequences differed from those found in living New Guineans and Australian Aboriginals. Homo sapiens must have met and mated with two populations of Denisovans—one in mainland Asia and one in Southeast Asia, says EVA paleogeneticist Diyendo Massilani—further evidence that they were once numerous and wide-ranging.

The Denisovans bequeathed a particular genetic gift to modern Tibetans: a “superathlete” variant of a gene, called EPAS1, that helps red blood cells use oxygen efficiently and is found in Denisovans from Denisova Cave. Zhang and her colleagues think the Tibetan Plateau Denisovans may have been adapted to life at high altitude, and that EPAS1 may have spread widely among them, before they handed it on to modern Tibetans.

But molecular dating suggests EPAS1 spread rapidly only in the past 5000 years. And natural selection would have favored that gene variant only in people who lived at high altitude year-round, says archaeologist Mark Aldenderfer, professor emeritus at the University of California, Merced. The Denisovans may have lived only seasonally in the cave. Zhang’s team will need to find nuclear DNA to test its hunch.

 Zhang expects more digs at the cave will clarify the issue with DNA and perhaps fossils. “The study of this cave is only beginning,” she says.

*Correction, 29 October, 3:15 p.m.: Katerina Douka’s affiliation has been corrected.

Taking the politicians out of tough policy decisions; the late, great works of Charles Turner; and the science of cooking

bee with podcast symbol overlay

Biodiversity Library/Flickr

First up, host Sarah Crespi talks to News Intern Cathleen O’Grady about the growing use of citizens’ assemblies, or “minipublics,” to deliberate on tough policy questions like climate change and abortion. Can random groups of citizens do a better job forming policy than politicians?

Next, we feature the latest of a new series of insight pieces that revisit landmark Science papers. Sarah talks with Hiruni Samadi Galpayage Dona, a Ph.D. student at Queen Mary University of London, about Charles Turner, a Black zoologist who published multiple times in Science in the early 1900s. Despite being far ahead of his time in his studies of animal cognition, Turner’s work was long overlooked—due in large part to the many difficulties facing a Black man in academia at the turn of the century.

Finally, in our monthly books segment, host Kiki Sanford chats with author Pia Sorensen about her new book: Science and Cooking: Physics Meets Food, From Homemade to Haute Cuisine.

This week’s episode was produced with help from Podigy.

Listen to previous podcasts.

About the Science Podcast

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Salmon study sheds light on why fall-run fish are bigger than their spring-run cousins

Some Chinook salmon return to freshwater rivers in the spring, but others migrate in the fall.

Mark Conlin Visual&Written/Newscom

For the Yurok people, who have lived at the mouth of the Klamath River for generations, the spring run of Chinook salmon (Oncorhynchus tshawytscha) is a welcome—and nutritious—relief from winter. But as the fish have dwindled to just a fraction of their original numbers, Indigenous groups there are pushing to have them protected by the Endangered Species Act. New research, which suggests genes play only a small role in distinguishing the spring salmon from their fall-run cousins, may call into question the need for such a designation.

The rivers of the Pacific Northwest used to teem with two waves of Chinook: those that arrived in March or April, and those that came 6 months later, swimming from the sea to their upriver breeding grounds. Although technically the same species, the spring-run and fall-run fish have some “iconic differences,” says Eric Anderson, a molecular geneticist at the National Oceanic and Atmospheric Administration’s Southwest Fisheries Science Center. Spring salmon are smaller, fattier, and less sexually mature than fall fish. They also swim further upriver to breed.  

To tease out the genetic basis of those differences, Anderson and colleagues teamed up with Yurok fishers living at the mouth of the Klamath River in northern California. Together, they examined 500 fish as they started their upstream journeys in all four seasons. The researchers measured the size of each fish, assessed its fattiness and reproductive status, and took samples of its DNA. The researchers gathered similar data from other rivers.

Past studies have shown that a small region of the salmon chromosome 28 contains two genes, GREB1L and ROCK1, that vary between spring and fall salmon. Anderson and his colleagues did further genomic studies, sequencing the whole genomes of 160 fish in the hopes of linking the two genes to the spring and fall traits. The data set is “impressive” and the work unique says Sheela Phansalkar Turbek, an evolutionary biologist at the University of Colorado, Boulder, who was not involved with the work.

The researchers found that, although spring-run fish had one version of the genes and fall-run fish had another, the genes had nothing to do with how fat or mature the salmon were, they report today in Science. Instead, the team concludes these differences exist because fall-run salmon are measured months after the spring salmon, giving them more time to fatten up in the ocean. “The cool thing about this paper is it shows that a lot of differences can be explained by timing,” says Michael Miller, a geneticist at the University of California, Davis, who helped pin down the variant genes, but was not involved with the new work. “There’s a whole cascade of effects that come from [simply] changing the timing.”

The new data also show that fall-run and spring-run salmon often interbreed, Anderson says. DNA analyses—and data from migrating fish—reveal that hybrids usually begin their journeys between spring and fall, often in the middle of summer. And a computer simulation in the new study suggests interbreeding occurred long before humans modified the riverscape with the dams that prevent many spring salmon from reaching their upriver breeding grounds. “It’s been a long ongoing natural process of gene exchange,” Anderson says.

In some ways, this work challenges the idea that the two fish should be categorized and managed separately, Turbek says.  Some researchers have proposed that spring-run fish might re-emerge from the population of hybrids or from spring-run salmon introduced from other rivers. But others are concerned that such efforts could falter—or introduce new diseases to the environment. It’s “not the sort of thing we can count on,” Miller says.

He also thinks interbreeding has risen sharply in recent years because of dams and other human modifications to rivers that make it more likely that spring-run and fall-run salmon breed in the same pools. As bigger fall-run fish outcompete spring-run fish, those early arrivers—and their version of the gene that dictates migration timing—may disappear. “Spring salmon are headed towards extinction in the Klamath and practically every other watershed in Pacific Northwest,” says Craig Tucker, an independent biologist and consultant to the Karuk Tribe, which petitioned to have spring-run salmon protected.

Tucker is concerned this new study is “muddying the scientific waters” and could slow the process of getting protection for these salmon. Miller agrees. But Anderson says the true strength of the work is that it shows the importance and uniqueness of the spring-run genes, and not just in the Klamath River. “It stresses that they should be conserved throughout the species.”

*Correction, 29 October, 4:15 p.m. In the initial version of this story, the wrong tribe was identified as living at the mouth of the Klamath River and working with these researchers.

‘Myopic’ funding cuts may force Mexican scientists to leave major international organizations

The 2018 World Meeting for Women in Mathematics in Rio de Janeiro was organized by the International Mathematical Union, one of the global organizations Mexico may be forced to leave.

Luz de Teresa

On 9 October, Tonatiuh Matos, president of the Mexican Physical Society (SMF), received an email that he says left him speechless. In it, the National Council of Science and Technology (CONACYT), Mexico’s main science funding agency, notified Matos it would no longer pay the society’s membership dues for the International Union of Pure and Applied Physics (IUPAP). The funds will be redirected to the fight against COVID-19.

Many other national science organizations tell ScienceInsider they have recently received similar letters from CONACYT. The agency has canceled funding for memberships in organizations as diverse as the International Mathematical Union, the Latin American Biology Network, the Third World Academy of Sciences, the International Science Council, and the Global Biodiversity Information Facility.

Unless they can find ways to pay for the memberships—a tall order given that some dues exceed $100,000—the move could lead to a withdrawal from the global science scene that scientists warn will isolate Mexico scientifically and deprive it of opportunities. “There will be no new ideas, there will be no new technology and therefore there will be no new developments, no innovation,” Matos says.

CONACYT’s cut is just the latest blow to the societies, most of which largely depend on government subsidies; membership fees alone don’t suffice to pay for activities such as conferences, science education, and participation in R&D projects. Mexican President Andres Manuel López Obrador has accused the groups, along with many other civil society organizations, of “corruption” and misusing government funding, and in February 2019 he ordered federal agencies to stop supporting the organizations. In response, CONACYT began to cut the science groups’ annual budgets.

“The government is presenting a negative image to the people of what we are. All those funds they gave to our associations were not for our salaries, they were to support the dissemination of science,” says Ignacio González, president of the Mexican Chemical Society, which received only 40% of its expected annual budget last year and nothing for this year.

CONACYT did not respond to requests for comment from ScienceInsider.

SMF had trouble last year paying its dues for the Ibero-American Federation of Physical Societies, the Latin American Centre for Physics, and the Canadian-American-Mexican Graduate Student Physics Conference, all of which come out of its general budget. Now, CONACYT has canceled a specific budget item for its dues at IUPAP, the world’s largest physics society—“the most important of all memberships,” Matos says.

Leaving international science organizations means missing out on membership benefits such as financial aid to attend meetings and workshops, free access to publications and networking activities, and the chance to host international conferences. Mexico will also forfeit its influence in decisions that affect regional and global science.

International collaboration is fundamental for the development of science.

María de la Luz Jímena de Teresa, Mexican Mathematical Society

For instance, María de la Luz Jímena de Teresa, former president of the Mexican Mathematical Society, says she and other Latin American representatives successfully lobbied the International Mathematical Union to appoint a Colombian scientist to oversee its policies for developing countries—“someone with knowledge of the facts,” she says. Membership in the union also enabled her society to organize workshops to promote gender equality in science and schools for the development of math in Latin America and the Caribbean.

Others stress that Mexico’s presence in international groups benefits other countries as well. As a biodiversity hot spot, the country is a vital participant in the Global Biodiversity Information Facility, an international network and data infrastructure, says Patricia Koleff, head of the facility’s Mexican delegation. Working with constrained resources has taught Mexican scientists to do a lot with relatively little, a skill that they can teach others, Gonzáles says. “Our society’s circumstances have given us a strong improvisation capacity.”

Mexican societies hope they can keep their memberships going through other activities, including by raising money from workshops and donations. They’re also trying to negotiate discounts or payment extensions. But Matos says budgets may simply be too tight: “This year we managed to stay afloat only because everything was suspended due to the pandemic. SMF received 13% of the normal budget. If it continues like this, next year we will have to stop almost all the society’s activities.”

Scientists understand Mexico’s dire economic situation and the need for sacrifices, but withdrawing from the global scene is “a very myopic way to look at what science is,” Jímena de Teresa says. “International collaboration is fundamental for the development of science.” 

Trump catalyzed the March for Science. Where is it now?

In 2017, the March for Science attracted nearly 1 million demonstrators worldwide, including many who jammed the streets of Washington, D.C.

Bill Douthitt/AAAS

On 22 April 2017, just 3 months after the inauguration of President Donald Trump, more than 1 million demonstrators around the world took to the streets for an unprecedented event: the March for Science. The event, designed to demonstrate public support for science, was a “lightning in a bottle moment” inspired largely by the antiscience stances taken by the fledgling Trump administration, says Lucky Tran, one of many volunteers with research backgrounds who helped transform the idea, initially floated by a few people on social media, into a high-profile happening complete with sometimes nerdy signs that became internet sensations.

Even before the march ended, however, many organizers, participants, and onlookers wondered: Could the March for Science—which became a nonprofit organization with about 1 million social media followers—translate its early success into sustained influence?

Now, as Trump runs for reelection, the answer is becoming clearer. Although the March for Science has not replicated its initial splash—a 2018 march drew far fewer participants—and has sometimes struggled to define concrete goals, observers say the effort continues to resonate, albeit in ways that can be hard to measure.

The march attracted “a lot of new people … that had never engaged with science policy or science advocacy before” but now see such engagement as important, says Tran, managing director of the March for Science who trained as a molecular biologist and works as a science communicator at Columbia University. And although demonstrators might not have remained directly engaged with the March for Science, many have been “channeled into other events and other organizations that captured their imagination and kept them engaged for longer,” says sociologist Dana Fisher of the University of Maryland, College Park, who studies social movements spawned by opposition to the Trump administration.

The March for Science organization itself has remained small. In the past year, its $300,000 budget has supported a staff that has fluctuated from three to five full-time employees, as well as four to six part-time employees. It also spent $12,000 on advocacy through a platform that makes it easy for followers to contact their elected officials en masse about science-related issues, such as the recent push to persuade municipal, county, and state elected representatives to adopt U.S. Centers for Disease Control and Prevention guidelines for curbing the COVID-19 pandemic. The group maintains an active email list of about 220,000 and often posts multiple videos a week to its Facebook page, which boasts just shy of 1 million followers.

The group’s current president, Matt Tranchin, has no formal background in research or science, but does bring outreach experience from a previous post, working in the White House Office of Public Engagement under former President Barack Obama. Researchers note Tranchin’s background reflects the broader makeup of the March for Science leadership and following; data from the 2017 march, for example, suggests that only a minority of its followers are practicing scientists, Fisher says. (March for Science leaders say their aim is to inspire support for science-based policies from people of all backgrounds.)

The group has addressed early criticism about lacking concrete goals by choosing specific, yearlong projects to tackle. This year, for example, it has partnered with the government of Samoa and the Alliance of Small Island States to push nations to publicly acknowledge a report from the Intergovernmental Panel on Climate Change that suggests world leaders must commit to measures stronger than previously thought in order to prevent global warming of 1.5°C or more. March for Science has also hosted video discussions of science-related policies and connected its social media followers with other organizations engaged in science advocacy.

In the lead-up to the U.S. elections, the group launched a Vote for Science social media campaign encouraging followers to vote. Although the group does not endorse candidates, in April, on Earth Day, former Vice President Joe Biden (now the Democratic nominee for president) addressed the March for Science community in a video posted to the group’s Facebook page. He encouraged supporters to continue to “raise [their] collective voices from a safe distance,” during the COVID-19 pandemic.

Tran, for one, believes the group’s efforts have helped set the stage for the unusual outpouring of political activism from the U.S. scientific community this election year. In October, for example, Scientific American publicly backed Biden in its first political endorsement in the outlet’s 175-year history. And NatureScience, and The New England Journal of Medicine have all published opinion pieces urging readers to vote against President Donald Trump. Not that long ago, he says, such activism might have seemed unlikely, but “we went there 4 years ago. … The hard work of everyone who participated in the March for Science really shifted … that conversation.”

The March for Science might no longer draw headlines, outside observers say. But it has become part of an evolving science advocacy ecosystem. “They’re definitely in the game,” says Michael Heaney, a political scientist at the University of Glasgow who studies social movements and conducted a randomized survey of participants at the 2017 March for Science in Washington, D.C. “They’re raising their voice … they’re projecting their ideas,” he says, and “they’re doing it consistently.”

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United Kingdom lights up its unusual fusion reactor

A computer simulation of a plasma inside the United Kingdom’s new experimental fusion reactor


The United Kingdom’s revamped fusion reactor, known as the Mega Amp Spherical Tokamak (MAST) Upgrade, powered up for the first time yesterday after a 7-year build. The £55 million device will be a testbed for technologies critical to all future fusion reactors, and may provide a stepping stone to a new design of energy-producing facility.

Tokamaks are the frontrunners in the decadeslong effort to generate energy by fusing light elements together. These doughnut-shaped vessels contain a superhot ionized gas—or plasma—of hydrogen isotopes that is constrained with powerful magnets and heated by microwaves and particle beams. (ITER, a gigantic tokamak under construction in France, is a major focus of global efforts to realize fusion power.)

MAST is a variation on the standard tokamak; it is shaped more like a cored apple than a doughnut. Researchers believe that shape can confer greater stability in the roiling plasma than a doughnut-shaped tokamak, but it is less well understood than the traditional design. MAST first tested the concept on a large scale starting in 1999 and has now been upgraded with extra heating power, new technology for extracting heat from the plasma, and other improvements. A parallel effort at the Princeton Plasma Physics Laboratory, called the National Spherical Torus Experiment (NSTX), was similarly upgraded. Soon after restarting in 2016, however, NSTX suffered a magnet failure and is now being rebuilt. 

U.K. researchers hope MAST Upgrade will demonstrate enough improvement in performance that they can move ahead with a plan for building a spherical tokamak demonstration power plant. They started to work on a design for the Spherical Tokamak for Energy Production last year with £220 million in government funding and hope to be powering up this next-generation machine in 2040. uluslararası evden eve nakliyat, uluslararası evden eve nakliyat, kayseri evden eve nakliyat, kayseri asansör kiralama, kayseri evden eve nakliyat, uluslararası zati eşya taşımacılığı, kayseri asansör kiralama, kayseri kiralık asansör,,