Sunday, November 07, 2021

'MAYBE'TECH

US Department of Energy wants to dramatically reduce the cost of carbon capture technology


It's an ambitious target.


I. Bonifacic
@igorbonifacic
November 5th, 2021
Todd Korol / reuters


The US Department of Energy wants to accelerate the development of carbon capture technology. On Friday, the agency announced a program called Carbon Negative Shot. Part of its Energy Earthshots initiative, the goal here is to foster the development of carbon capture technology that can sequester CO2 at a cost of less than $100 per ton, and can be deployed at the gigaton scale. To put that in perspective, that much carbon is equivalent to the annual emissions of approximately 250 million cars.

“By slashing the costs and accelerating the deployment of carbon dioxide removal — a crucial clean energy technology — we can take massive amounts of carbon pollution directly from the air and combat the climate crisis,” said Secretary of Energy Jennifer M. Granholm. “With our Carbon Negative Shot, we can help remove the greenhouse gases already warming our planet and affecting our health — positioning America as a net-zero leader and creating good-paying jobs for a transitioning clean energy workforce.”

If it wasn’t clear already, the Energy Department has set an ambitious target. In September, Orca, the largest direct carbon capture facility ever, opened in Iceland. The plant will capture 4,000 tons of CO2 per year at a cost of about $600 per ton for bulk purchases. Chimeworks, the company that operates Orca, aims to reduce the cost to $300 or less per ton by 2030. That’s a long way away from the Energy Department’s goal of less than $100 per ton, but sustained and substantial support and investment from the government is exactly what could make that happen.

The US has big, new plans to pull CO2 out of the air

Collector containers at the ‘Orca’ direct air capture and storage facility, operated by Climeworks AG, in Hellisheidi, Iceland, on Tuesday, Sept. 7, 2021. Startups Climeworks and Carbfix are working together to store carbon dioxide removed from the air deep underground to reverse some of the damage CO2 emissions are doing to the planet. Arnaldur Halldorsson/Bloomberg via Getty Images

Despite the efforts of delegates at this month’s climate summit in Glasgow, the world is still careening toward potentially catastrophic levels of global warming. Now, some countries and corporations are turning to new technologies to pull carbon out of the air.

Today, the US Department of Energy (DOE) announced a bold new plan to make those technologies, called carbon dioxide removal (CDR) technologies, cost-effective and scalable with the launch of a new “Carbon Negative Shot” initiative. Through this initiative, the agency seeks to bring the cost of CDR down dramatically this decade — to less than $100 a ton — so that it can be deployed at a big enough scale to remove “gigatons,” or billions of tons, of carbon dioxide from the atmosphere.

That is a hell of a lot of CO2 pollution. Sequestering one gigaton of carbon dioxide would amount to removing the pollution of about 250 million vehicles — the US’s entire light-duty fleet — in one year, according to the DOE. With CDR technologies still in pretty early stages of development, there are significant hurdles to overcome before the DOE can do so.

CDR is a suite of strategies aimed at drawing down CO2 to keep it from trapping heat in the atmosphere. Nature can do some of that for us — trees and plants pull CO2 out of the air. There’s also “direct air capture” technology that mimics that process using carbon-sucking machines, but it has yet to be deployed at a large scale.

To draw down enough heat-trapping pollution, the US will likely need large-scale direct air capture plants. The largest direct air capture plant came online in Iceland earlier this year, and it’s only able to pull out 4,000 tons of carbon dioxide annually. That’s roughly equivalent to the emissions from 790 passenger vehicles in a year. To date, there are only 19 direct air capture plants around the world, according to the International Energy Agency, and they only have the capacity to capture a tiny fraction of what the DOE’s aims are.

Cost is one big reason why the tech hasn’t advanced further. Companies like Microsoft pay about $600 for each ton of CO2 the Iceland plant captures. The company pumped out the equivalent of 11,164,000 metric tons of carbon dioxide in its 2020 fiscal year. At $600 a ton, Microsoft would need to pay almost $6.7 billion to remove just one year of its pollution.

But cost isn’t the only challenge. Direct air capture plants trap CO2 using filters or chemical solutions. To release the trapped CO2 so that it can be safely stored, the filter or chemical solution needs to be heated up to very high temperatures — between 100 and 900 degrees Celsius. That takes a lot of energy. In a catch-22, the machines that pull carbon out of the air could wind up using as much as a quarter of the global energy supply by 2100, according to a 2019 study published in the journal Nature Communications. If that energy comes from burning fossil fuels, it could contribute to the problem it’s trying to solve. (And it’s still technically difficult to use purely renewable energy to reach the extremely high temperatures required for the chemical solution method of direct air capture.) That’s likely why the DOE says in its announcement today that it wants to ensure that “emissions created when running and building the removal technology are accounted for.”

Lastly, the DOE is aiming to secure places to store CO2 where it can be monitored for at least 100 years. It ideally needs to stay sequestered for much longer to keep humanity from falling deeper into climate crisis. At the Iceland plant, CO2 is pumped underground, where the companies behind the project say it can be stored in rock formations for thousands of years. Volcanically active Iceland has relatively young and porous basalt rock that’s ideal for this kind of storage.

The US will not only need to find similarly well-suited locations — it’ll need to transport it there via new pipelines. The Biden administration’s infrastructure bill that’s inching closer to a final vote includes billions of dollars for new pipelines, and $3.5 billion for four direct air capture “hubs.” That already has some environmental groups concerned about pipeline ruptures, like one that sickened residents of a small, majority-Black community in Mississippi last year. At high concentrations, carbon dioxide is a dangerous asphyxiant.

Despite all those challenges, leading climate scientists working with the United Nations have included carbon removal in roadmaps for limiting the climate crisis to somewhat manageable levels. That’s gotten criticism from some progressive activists who see carbon removal as a distraction from transitioning from fossil fuels to renewable energy. And even experts optimistic about the future of the technology caution that it’s meant to be a side dish and not the main course in any plan to combat climate change.

“It is at most a supplement that can help us reduce climate change,” David Morrow, director of research at the Institute for Carbon Removal Law and Policy at American University, told The Verge in September when the Iceland plant came online. “But it can’t take the place of cutting emissions.”

The US, the world’s second-biggest CO2 polluter, still needs to focus primarily on finding alternatives to fossil fuels so that it can prevent greenhouse gas emissions in the first place.

Fractured artificial rock helps crack a 54-year-old mystery

Fractured artificial rock helps crack a 54-year-old mystery
Princeton researchers have developed a technique to better understand how polymers 
flow through small channels under pressure. Credit: David Kelly Crow

Princeton researchers have solved a 54-year-old puzzle about why certain fluids strangely slow down under pressure when flowing through porous materials, such as soils and sedimentary rocks. The findings could help improve many important processes in energy, environmental and industrial sectors, from oil recovery to groundwater remediation.

The fluids in question are called  solutions. These solutions—everyday examples of which include cosmetic creams and the mucus in our noses—contain dissolved polymers, or materials made of large molecules with many repeating subunits. Typically, when they're put under pressure, polymer solutions become less viscous and  faster. But when going through materials with lots of tiny holes and channels, the solutions tend to become more viscous and gunky, reducing their flow rates.

To get at the root of the problem, the Princeton researchers devised an innovative experiment using a see-through porous medium made of tiny glass beads—a transparent artificial rock. This lucid medium allowed the researchers to visualize a polymer solution's movement. The experiment revealed that the long-baffling increase in viscosity in porous media happens because the polymer solution's flow becomes chaotic, much like turbulent air on an airplane ride, swirling into itself and gumming up the works.

"Surprisingly, until now, it has not been possible to predict the viscosity of polymer solutions flowing in porous media," said Sujit Datta, an assistant professor of chemical and biological engineering at Princeton and senior author of the study appearing Nov. 5 in the journal Science Advances. "But in this paper, we've now finally shown these predictions can be made, so we've found an answer to a problem that has eluded researchers for over a half-century."

"With this study, we finally made it possible to see exactly what is happening underground or within other opaque, porous media when polymer solutions are being pumped through," said Christopher Browne, a Ph.D. student in Datta's lab and the paper's lead author.

Browne ran the experiments and built the experimental apparatus, a small rectangular chamber randomly packed with tiny borosilicate glass beads. The setup, akin to an artificial sedimentary rock, spanned only about half the length of a pinky finger. Into this faux rock, Browne pumped a common polymer solution laced with fluorescent latex microparticles to help see the solution's flow around the beads. The researchers formulated the polymer solution so the material's refractive index offset light distortion from the beads and made the whole setup transparent when saturated. Datta's lab has innovatively used this technique to create see-through soil for studying ways to counter agricultural droughts, among other investigations.

Browne then zoomed in with a microscope on the pores, or holes between the beads, which occur on the scale of 100 micrometers (millionths of a meter) in size, or similar to the width of a human hair, in order to examine the  through each pore. As the polymer solution worked its way through the porous medium, the fluid's flow became chaotic, with the fluid crashing back into itself and generating turbulence. What's surprising is that, typically, fluid flows at these speeds and in such tight pores are not turbulent, but "laminar": the fluid moves smoothly and steadily. As the polymers navigated the pore space, however, they stretched out, generating forces that accumulated and generated turbulent flow in different pores. This effect grew more pronounced when pushing the solution through at higher pressures.

"I was able to see and record all these patchy regions of instability, and these regions really impact the transport of the solution through the medium," said Browne.

Fractured artificial rock helps crack a 54-year-old mystery
Princeton researchers have developed a technique to better understand how polymers flow through small channels under pressure. Credit: David Kelly Crow

The Princeton researchers used data gathered from the experiment to formulate a way to predict the behavior of polymer solutions in real-life situations.

Gareth McKinley, a professor of mechanical engineering at the Massachusetts Institute of Technology who was not involved in the study, offered comments on its significance.

"This study shows definitively that the large increase in the macroscopically observable pressure drop across a porous medium has its microscopic physical origins in viscoelastic flow instabilities that occur on the pore scale of the porous medium," McKinley said.

Given that viscosity is one of the most fundamental descriptors of fluid flow, the findings not only help deepen understanding of polymer solution flows and chaotic flows in general, but also provide quantitative guidelines to inform their applications at large scales in the field.

"The new insights we have generated could help practitioners in diverse settings determine how to formulate the right polymer  and use the right pressures needed to carry out the task at hand," said Datta. "We're particularly excited about the findings' application in groundwater remediation."

Because polymer solutions are inherently goopy, environmental engineers inject the solutions into the ground at highly contaminated sites such as abandoned chemical factories and industrial plants. The viscous solutions help push out trace contaminants from the affected soils. Polymer solutions likewise aid in oil recovery by pushing oil out of the pores in underground rocks. On the remediation side, polymer solutions enable "pump and treat," a common method for cleaning up groundwater polluted with industrial chemicals and metals that involves bringing the water to a surface treatment station. "All these applications of polymer solutions, and more, such as in separations and manufacturing processes, stand to benefit from our findings," said Datta.

Overall, the new findings on  flow rates in  brought together ideas from multiple fields of scientific inquiry, ultimately disentangling what had started out as a long-frustrating, complex problem.

"This work draws connections between studies of polymer physics, turbulence, and geoscience, following the flow of fluids in rocks underground as well as through aquifers," said Datta. "It's a lot of fun sitting at the interface between all these different disciplines."

Tiny polymer springs give a boost to environmental cleanup
More information: Christopher A. Browne et al, Elastic turbulence generates anomalous flow resistance in porous media, Science Advances (2021). DOI: 10.1126/sciadv.abj2619. www.science.org/doi/10.1126/sciadv.abj2619
Journal information: Science Advances 
Provided by Princeton University 
Guinea junta names AngloGold executive as mines minister

Cecilia Jamasmie | November 5, 2021 

Siguiri gold mine is AngloGold’s only operation in Guinea. (Image courtesy of AngloGold Ashanti.)

Guinea’s junta has appointed Moussa Magassouba, the director general of AngloGold Ashanti’s (JSE: ANG) (NYSE: AU) local subsidiary as the country’s mines and geology minister, two months after the army unit overthrew President Alpha Conde.


Magassouba, a western educated mining engineer and fluent English speaker, has more than 20 years’ of experience in the industry. He joined AngloGold Guinea in 2016 and held the role of managing director.

Experts, such as Eric Humphery-Smith, Africa analyst at risk consultancy Verisk Maplecroft, believe Magassouba’s nomination is a positive step towards putting mining executives’ minds to rest.
Moussa Magassouba. (Image: Siguiri mine.)

“The fact that Magassouba is a pure technocrat, with no obvious political experience, is reassuring for operators,” Humphery-Smith wrote. “It also proves that the National Rallying Committee for Development (CNRD) — one of the four institutions or figures in charge of the transition — is attentive to industry stakeholders.”

Abé Sylla, a United States-based businessman, has been appointed as energy and hydrocarbons minister, while artist Alpha Soumah was named culture minister.

Guinea is the world’s top exporter of bauxite, which is refined into alumina and then smelted to produce aluminum. The reddish ore accounts for most of the West African nation’s mining exports, though the country also has vast deposits of iron ore, gold and diamonds.

While the coup has been condemned by Guinea’s neighbours and exacerbated concerns about supply constraints that pushed aluminum prices to the highest level in 13 years, the junta took early steps to reassure miners.

One of its first actions was to lift a curfew in mining areas, urging companies to keep operating and keeping the nation’s ports open.

The junta also unveiled a “transitional charter” that it says will steer the country back to civilian rule.
Apolitical

Magassouba’s job will be specially challenging, Humphery-Smith says, due mainly to his lack of experience in politics.

“The largely apolitical nature of Magassouba’s profile means we expect him to give way to the junta’s policy directives. Indeed, the Transition Charter makes it explicitly clear that Doumbouya and the CNRD will instruct the government on policy matters,” the Verisk Maplecroft analyst says.

The expert notes the junta’s slow decision-making pace to date, hints that the government will not be “especially responsive” to the private sector.

Besides Australia, Guinea is one of China’s largest supplier of bauxite. Yet poverty remains endemic as the ore is sent as raw material, with little effort made so far to transform it locally.

The country’s new leadership has said its focus will be to accelerate the second phase of the mining value chain by boosting local processing.

Leaders of the 15-nation regional bloc Economic Community of West African States (ECOWAS), from which Guinea is currently suspended, meet on Sunday to discuss the situation in the country as well as in neighbouring Mali, where a junta took power last year.

ECOWAS has demanded that the Guinea junta organize elections by the end of March 2022.
PERU
Antamina CEO seeks ‘common ground’ after protests

Reuters | November 5, 2021 

Víctor Gobitz, president of Peruvian Institute of Mining Engineers (Gestion)

The head of Antamina, Peru’s largest copper producer, looked to defuse tensions with rural community protesters on Friday, addressing residents in a town-hall meeting after a blockade forced the mining firm to suspend operations last week.


Victor Gobitz, head of Antamina, part-owned by Glencore Plc and BHP Billiton, told residents at a town hall meeting in Aquia attended by Reuters that the two sides could find common ground, a sharp shift from an earlier critical tone.

“With orderly dialogue we will find the formula for a development plan for the whole town of Aquia,” Gobitz said at the meeting hold in the town’s bull fighting arena. “We have to lead by example that we can find common ground.”

The tone was a marked shift for Gobitz, who initially dismissed the protesters as violent and only representative of a minority of voices. Gobitz arrived in rural Aquia for the meeting with residents on Friday in a government helicopter.

Protests against miners in Peru, the world’s No. 2 copper producer, have escalated in recent weeks amid high expectations from rural communities emboldened by the socialist administration of center-left President Pedro Castillo.

Castillo, from a peasant farming background, came to power in July with massive support from mining regions, promising to hike taxes on miners to promote local development.

The community in Aquia, located some 60 kilometers (37 miles) from Antamina, had blocked a key road for the mine in late October, before agreeing to lift the blockade after government talks earlier this week.

Residents say the area receives little in terms of tax contributions from the mine, while the company has a copper pipeline and road running through the town.

“We are not throwing a social tantrum,” said Adan Damian, the president of Aquia, in remarks in response to Gobitz. “I have mixed feelings that after protesting so much we are finally being listened to.”

Aquia residents are hoping to sign a formal agreement with Antamina later on Friday. Gobitz’s presence indicates a positive resolution is highly likely.

(By Marcelo Rochabrun; Editing by Adam Jourdan and Marguerita Choy)
Copper giants safe in our hands, Chile leftist’s campaign says
Bloomberg News | November 5, 2021 |

Gabriel Boric. Credit: Department of Public Policy at CEU

Mining heavyweights such as BHP Group and Anglo American Plc have nothing to fear if former student protest leader Gabriel Boric becomes Chile’s next president, according to one of his top advisers.


While a Boric government would raise taxes to help fund a green transformation, it wouldn’t overburden the industry by removing incentives to invest, said Willy Kracht in a telephone call Thursday. The left-leaning candidate wants the state to play a more active role in technology projects and lithium extraction, but has no plans to interfere in any existing concessions.

“There’s no intention to change the rules of the game, just to strengthen institutionality so that things function better,” said Kracht, who is head of the mine engineering department at the University of Chile and a director at copper research center CESCO.

Just two weeks away from the first round of voting, the comments may go some way to easing concern that a Boric victory would stifle investment in a country that accounts for more than a quarter of mined copper.

Mining companies have warned that a royalty bill currently before congress would erode Chile’s competitiveness by creating one of the heaviest tax burdens among major copper nations.

Still, government and industry representatives agree that there is scope to lift taxes in some form. Boric’s proposal is two-pronged — a royalty on sales and a sliding levy on profit. That would raise the equivalent to an additional 1% of gross domestic product.

“That mixed structure — with ad valorem and progressive components — should work better in terms of collection without putting at risk the feasibility of development projects,” Kracht said, without offering proposed rates.

He also said there’s considerable consensus on what has to be done in terms of decarbonization and social engagement.

One priority of the Boric team is to set up a development bank that helps fund technology in collaboration with the private sector. For example, the state could help fund a privately-run project for mines to convert to electric trucks, which could then be marketed as a solution in neighboring countries.

Boric’s program also prioritizes the development of state companies Codelco and Enami and will look to promote investments in local refining, as well as gradually raising carbon and fuel taxes.

(By James Attwood)
Massive comet exploding over Chile 12,000 years ago may have created strange glassy rocks


By Meghan Bartels 3 days ago

Dark silicate glass is seen against the Atacama Desert in northern Chile.
(Image credit: P.H. Schultz/Brown University)

Be grateful you weren't in what is now Chile's Atacama Desert 12,000 years ago.

Today, a 47-mile (75 kilometers) swath of the desert is strewn with strange dark, glassy rocks that have long puzzled scientists. New research finds that those rocks are quite similar to comet particles collected by a NASA mission. The scientists behind the work now think that all those years ago, one or more huge comets exploded together in the skies over the region, causing tornado-force winds, scorching a wet, grassy landscape, and scattering the area with warped and twisted glass that still contains minerals generally found only in meteorites.

"This is the first time we have clear evidence of glasses on Earth that were created by the thermal radiation and winds from a fireball exploding just above the surface," Pete Schultz, a geologist at Brown University in Rhode Island, said in a statement.

"To have such a dramatic effect on such a large area, this was a truly massive explosion," he said. "Lots of us have seen bolide fireballs streaking across the sky, but those are tiny blips compared to this."

Schultz and his colleagues wanted to compare the strange Chilean glass, which ranges from dark green to black, with the work of a NASA mission called Stardust, which launched in 1999. Stardust visited a comet called Wild-2 to trap particles of its dust, which the spacecraft delivered to Earth in 2006. The samples were scientists' first-ever pristine samples of cometary dust from out beyond the orbit of the moon, according to NASA.

For the new research, Schultz and his colleagues collected 300 pieces of the strange glassy rock to analyze from two patches of the region. In addition, the team cut thin, polished slices out of 20 of those samples to study under a microscope. In all of those slices, the researchers found dozens of grains and fragments that didn't match the region.

Those anomalies included a mineral called troilite, which is typically found in meteorites, and decomposed zircons that suggest the samples reached temperatures hotter than 3,000 degrees Fahrenheit (1,670 degrees Celsius). Other traits the researchers noted aren't exclusive to meteorites but are quite common in an extraterrestrial context and match what scientists have seen in meteorites or the Wild-2 samples.

"Those minerals are what tell us that this object has all the markings of a comet," Scott Harris, a planetary geologist at the Fernbank Science Center in Atlanta and a co-author on the new study, said in the same statement. "To have the same mineralogy we saw in the Stardust samples entrained in these glasses is really powerful evidence that what we're seeing is the result of a cometary airburst."

In addition, the researchers noted signs of a dramatic past on the glass, which show "sliding, shearing, twisting, rolling, and folding (in some cases, more than twice) before being fully quenched," the scientists wrote in the paper.

Scientists have considered other scenarios to explain the strange glass over the years. At the time, the region featured oases and grassy wetlands, so some have suggested that vast grass fires could have melted the sandy soil to form the glassy rocks.

"There may be lots of these blast scars out there, but until now we haven't had enough evidence to make us believe they were truly related to airburst events," Schultz said. "I think this site provides a template to help refine our impact models and will help to identify similar sites elsewhere."

Scientists can't yet precisely date the glassy rocks, although other research on the phenomenon has suggested the strange rocks formed between 12,300 and 11,500 years ago.

Intriguingly, that's close to the time when the remains of large mammals like horses and ground sloths stop showing up in the fossil record, and around when some scientists think humans started building settlements in northern Chile — although there's no way to know right now whether any of the three events are connected.

"It's too soon to say if there was a causal connection or not, but what we can say is that this event did happen around the same time as when we think the megafauna disappeared, which is intriguing," Schultz said. "There's also a chance that this was actually witnessed by early inhabitants, who had just arrived in the region. It would have been quite a show."

The research is described in a paper published Tuesday (Nov. 2) in the journal Geology.

An ancient fireball turned kilometres of the world's driest desert into glass

Ashley Strickland
CNNDigital
Thursday, November 4, 2021 


Researchers believe the Atacama Desert in Chile was the site of an ancient comet explosion intense enough to create giant slabs of silicate glass, according to a new study
. (P.H. Schultz/Brown University/CNN)

The Atacama Desert in Chile has been used as a way to simulate alien environments, like Mars on Earth. Now, researchers believe it was the site of an ancient comet explosion intense enough to create giant slabs of silicate glass, according to a new study.

The research published Tuesday in the journal Geology.

About 12,000 years ago, intense heat turned Atacama's sandy soil into vast areas of glass stretching for 75 kilometres, but researchers weren't sure what caused such a drastic change.

The Atacama Desert is the driest desert region on Earth, with incredibly little moisture or precipitation. The fragmented desert glass contains tiny mineral fragments that are often found in meteorites that land on Earth.

The minerals found in this glass matched up with particles collected by NASA's Stardust mission, which sampled a comet known as Wild 2.

The researchers are confident that the minerals found in the Chilean desert are what's left after a comet similar to Wild 2 exploded over the sands and melted them.

"This is the first time we have clear evidence of glasses on Earth that were created by the thermal radiation and winds from a fireball exploding just above the surface," said Pete Schultz, study author and a professor emeritus of geological science at Brown University and research professor at Brown's department of earth, environmental and planetary sciences, in a statement. "To have such a dramatic effect on such a large area, this was a truly massive explosion. Lots of us have seen bolide (bright meteor) fireballs streaking across the sky, but those are tiny blips compared to this."

The startling fields of glass, which appear dark green or black, stretch across an area east of the Pampa del Tamarugal plateau, located between the Andes Mountains and the Chilean Coastal Range.

While volcanic activity can create this kind of glass, there was no evidence to support that the Atacama glass was formed that way.

Previously, researchers have suggested that ancient fires were the cause.The area once hosted grassy wetlands derived from rivers. If those ancient grasses burned in widespread wildfires, some believe it may have created the glass.

However, the glass itself is more complicated. Up close, it appears the glass pieces had been twisted, folded, rolled and thrown while they were still molten. This, the researchers say, would only be possible with an airburst explosion that can unleash winds rivaling those of tornadoes.

A chemical analysis of the glass revealed zircons, or minerals that thermally decomposed to form baddeleyite crystals. This change can only happen when temperature spike above 3,000 degrees Fahrenheit or 1648 degrees Celsius, which would definitely exceed the heat generated by grass fires.

The analysis also showed minerals like cubanite and troilite, both found in the Wild 2 comet and meteorites.

"Those minerals are what tell us that this object has all the markings of a comet," said Scott Harris, study coauthor and a planetary geologist at the Fernbank Science Center in Georgia, in a statement. "To have the same mineralogy we saw in the Stardust samples entrained in these glasses is really powerful evidence that what we're seeing is the result of a cometary airburst."

The researchers want to focus on dating the glass to determine its exact age, as well as the potential size of the comet, but their current expectation that the impact occurred 12,000 years ago aligns with when large mammals disappeared from the area.

"It's too soon to say if there was a causal connection or not, but what we can say is that this event did happen around the same time as when we think the megafauna disappeared, which is intriguing," Schultz said. "There's also a chance that this was actually witnessed by early inhabitants, who had just arrived in the region. It would have been quite a show."

 MUTUAL AID VS SPENCERIAN SOCIAL DARWINISM

Sabre-toothed cats cared for each other when injured, fossil evidence suggests

A cat with a painful hip disability lived a long life, suggesting

 it had help on the hunt

This image is taken from the 1988 Mark Hallett mural Trapped in Time. It depicts saber-toothed cats digging into prey. A new study suggests that these ferocious killers shared their food with those unable to hunt for themselves. (La Brea Tar Pits)

Scientists have found that the fossilized remains of an adult sabre-toothed cat show signs that it lived with a congenital hip condition, suggesting that it lived in a social group with other cats who were able to help it hunt and feed.

The researchers identified the cat's pelvic bone showed evidence of long-term hip dysplasia, a developmental birth defect that is common in modern times in dogs and cats, but also well-known in humans.

The cat's fossilized remains were found in the La Brea Tar Pits in Los Angeles, an area the size of several city blocks. The pits have preserved the remains of animals that were trapped in sticky tar over tens of thousands of years.

Paleontologists have found a wealth of fossil remains in excavation of the pits.

The La Brea Tar Pits and Museum, which is part of the Los Angeles Natural History Museum, is home to a collection of the remains of about more than 2,000 extinct sabre-toothed cats, as well as many other animals, including other extinct animals like ground slots to mammoths.

Hips don't lie

The team of researchers, including paleontologist Mairin Balisi, decided to investigate a puzzling pattern.

A surprising number of fossils of Smilodon fatalis, the sabre-toothed cat that lived in the Los Angeles area up until about ten thousand years ago, showed evidence of hip damage.

The injuries were previously assumed to have been sustained from the aggressive hunting style required to bring down much larger prey than themselves, like bison.

But an in-depth study of that one pelvic bone found something else, which overturned that previous assumption.

Paleontologist Mairin Balisi holds a sabre-toothed cat pelvis. (Submitted by Mairin Balisi)

"A CT scan of this specimen at Cedar Sinai Hospital here in Los Angeles found no evidence of fractures," said Balisi, who is also a postdoctoral fellow at the La Brea Tar Pits and Museum.

"If this had been from an injury, there would have been fractures preserved in the bone. Instead, symptoms that supported the diagnosis of hip dysplasia were found," she told Quirks & Quarks host Bob McDonald.

Hip dysplasia occurs when the hip socket doesn't fully cover the ball portion of the thigh bone. Normally the top of the femur fits into the hip socket to create the hip joint. But in the case of hip dysplasia, there is an incomplete formation, or deformation of the hip socket.

"This condition would have degenerated over the animal's life, and so it would have started limping," Balisi said. "At some point, bone was rubbing on bone, and we see evidence of that in the skeleton. Hunting would have been painful and difficult."

The team's findings were published last month in Nature.

Why might big cats with bad hips be social? 

The fact that this sabre-toothed cat lived to adulthood with such a debilitating condition suggested to Balisi and her colleagues that it had help from other cats to survive.

This implied a degree of sociality in sabre-toothed cats not fully understood before. Cats today show a range of social behaviours but frequently live as largely solitary, territorial hunters. 

"It reached the same size as adult specimens that we have at the Tar Pits without this condition," Balisi said. "That suggests to us that it must have had enough food. We infer that it must have had help with some sort of food provisioning happening."

This may have taken the form of group hunting, in which the disabled cat wouldn't have had to take on the physically demanding role of taking down a large animal by itself.

This idea prompted Balisi to take a second look at some of the other sabre-toothed cat pelvic specimens in the collection. She wondered if they too had been mistakenly identified as having suffered an injury, instead of hip dysplasia. 

A three-dimensional scan of the pelvis and femur of a sabre-toothed cat showing hip dysplasia from the La Brea Tar Pits in Los Angeles. (La Brea Tar Pits)

"We did look at dozens of other specimens in the pathology collection at the La Brea Tar Pits, but it's difficult to make a definitive diagnosis of hip dysplasia without CT scans," she said.

"These specimens do show external signs that might be interpreted as hip dysplasia. Now with our study, we are prompted to reevaluate this."

If such reevaluation does find widespread evidence of hip dysplasia in sabre-toothed cats, it could help reinforce the case that these animals were consistently social. However, Balisi said other evidence will likely still be required, because it's difficult to be certain when it comes to understanding how extinct animals behaved.

"Sociality is very difficult to infer in the fossil record." she said.

"[However,] I think that it would be safe to say from our study that sabre-toothed cats lived in social groups. They were probably more social like lions rather than more solitary like tigers and leopards." 


Written and produced by Mark Crawley.