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Brain cells that give humans higher cognitive abilities are linked to neurological disorders

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Brain cells that give humans higher cognitive abilities over other animals are also linked to neurological disorders like schizophrenia, autism and epilepsy, a new study finds

  • Scientists have been on a quest to find what in the brain gives humans higher cognitive abilities over other animals
  • A team from Yale analyzed brain cells of humans and primates
  • They found five that are unique to humans, specifically a brain immune cell
  • This cell is also linked to neurological disorders, but experts say it could be what gives us our abilities  

By Stacy Liberatore For Dailymail.com

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Scientists have identified an immune brain cell unique to humans that gives us higher cognitive abilities over other animals, but what makes us specials also leaves us vulnerable to neurological disorders like schizophrenia, autism and epilepsy, a new study finds.

A team of neuroscientists from Yale analyzed cells found in the dorsolateral prefrontal cortex, the region involved in executive control functions, which is shared among humans and primates and narrowed it down to just five found only in the human brain, including an immune cell called microglia.

Microglia helps maintain the brain rather than warding off diseases and includes a gene, not present in primates, associated with neuropsychiatric diseases.

Lead author Nenad Sestan stated that we can ‘view the dorsolateral prefrontal cortex as the core component of human identity, but still we don’t know what makes this unique in humans and distinguishes us from other primate species.’

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Scientists have been on a long quest to find what in the brain gives humans higher cognitive abilities over other animals. A team from Yale says they found clues in the dorsolateral prefrontal cortex – a brain immune cell

The dorsolateral prefrontal cortex is tasked with switching and task-set reconfiguration, prevention of interference, inhibition planning, and working memory

Microglia is present from development and into adulthood, but scientists suspect it has implications for vulnerability to certain psychiatric disorders as individuals mature through adolescence.

‘Comparative studies suggest that human neurobiological development is unique,’ according to the team.

‘For example, humans differ from other primates in extending a rapid, fetal-like brain mass growth rate into the first postnatal year, thereby achieving relatively large adult brain size.’

The team found that the prefrontal cortex is present in humans and primates

The team analyzed more than 600,000 cell groups from the dorsolateral prefrontal cortex in both the primates (pictured) and humans. The results showed a single immune cell tasked with mainting the human brain could be involved with our high-level of cognition 

However, they wanted to find clues to what gives us higher cognition.

The team looked at more than 600,000 single-nucleus transcriptomes from adult human, chimpanzee, macaque and marmoset in the dorsolateral prefrontal cortex (dlPFC).

This led them to identifying which cells are unique to which species.

‘We humans live in a very different environment with a unique lifestyle compared to other primate species; and glia cells, including microglia, are very sensitive to these differences,’ Sestan said in a statement.

‘The type of microglia found in the human brain might represent an immune response to the environment.’

When the team analyzed the microglia they found the presence of the gene FOXP2 and variations of it have been linked to verbal dyspraxia, a condition in which patients have difficulty producing language or speech. 

Other studies have also shown that FOXP2 is associated with other neuropsychiatric diseases, such as autism, schizophrenia and epilepsy.

Sestan and colleagues found that this gene exhibits primate-specific expression in a subset of excitatory neurons and human-specific expression in microglia.

Shaojie Ma, a postdoctoral associate in Sestan’s lab and co-lead author, said in a statement: ‘FOXP2 has intrigued many scientists for decades, but still we had no idea of what makes it unique in humans versus other primate species.

‘We are extremely excited about the FOXP2 findings because they open new directions in the study of language and diseases.’

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Scientists discover how mosquitoes can ‘sniff out’ humans | Animal behaviour

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Whether you opt for repellant, long sleeves or citronella coils, the dreaded drone of a mosquito always seems to find its way back to you.

Now researchers say they have found the mechanism behind the insect’s ability to home in on humans.

Humans give off a fragrant cocktail of body odour, heat and carbon dioxide, which varies from person to person and mosquitoes use to locate their next meal. While most animals have a specific set of neurons that detect each type of odour, mosquitoes can pick up on smells via several different pathways, suggests the study, which is published in the science journal Cell.

“We found that there’s a real difference in the way mosquitoes encode the odours that they encounter compared to what we’ve learned from other animals,” said Meg Younger, an assistant professor of biology at Boston University and one of the lead authors of the study.

Researchers at the Rockefeller University, in New York, were baffled when mosquitoes were somehow still able to find people to bite after having an entire family of human odour-sensing proteins removed from their genome.

The team then examined odour receptors in the antennae of mosquitoes, which bind to chemicals floating around in the environment and signal to the brain via neurons.

“We assumed that mosquitoes would follow the central dogma of olfaction, which is that only one type of receptor is expressed in each neuron,” said Younger. “Instead, what we’ve seen is that different receptors can respond to different odours in the same neuron.”

This means losing one or more receptors does not affect the ability of mosquitoes to pick up on human smells. This backup system could have evolved as a survival mechanism, the researchers say.

“The mosquito Aedes aegypti is specialised to bite humans, and it is believed that they evolved to do that because humans are always close to fresh water and mosquitoes lay their eggs in fresh water. We are basically the perfect meal, so the drive to find humans is extremely strong,” said Younger.

Ultimately, the researchers say, understanding how the mosquito brain processes human odour could be used to intervene in biting behaviour and reduce the spread of mosquito-borne diseases, such as malaria, dengue and yellow fever.

“One major strategy for controlling mosquitoes is to attract them to traps to remove them from the biting population. If we could use this knowledge to understand how human odour is represented in the mosquito antennae and brain, we could develop blends that are more attractive to mosquitoes than we are. We could also develop repellants that target those receptors and neurons that detect human odour,” said Younger.

Dr Olena Riabinina, from the Insect Neuro Lab at Durham University, who was not involved in the research, said: “We already knew that mosquitoes are hard-wired to bite humans, but this research tells us that their olfactory system is different and more complex than we thought. Interventions based on this new information could be very promising.”

Dr Marta Andres Miguel, from University College London, who was also not involved, said: “This is a remarkable discovery not only from a fundamental biology perspective, but also from a disease-control perspective, as it opens new paths for the development of novel tools to control mosquitoes, either to attract them to traps, or to repel them and avoid human biting.”

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Humans may have passed monkeypox to their dog, report says

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The first suspected case of human-to-dog transmission of monkeypox has been reported in Paris, leading the U.S. Centers for Disease Control and Prevention to update its website to include dogs among animals susceptible to catching the virus.

The disease can spread between people and animals, said the CDC, which is studying which animals can contract monkeypox, which the United States declared a public health emergency this month. The CDC lists 10 animals, including dogs, that can be infected with monkeypox.

The evidence of spread from humans to dogs, published in the Lancet, could lead to further guidance on how pets should be cared for if they’re in a living space with an infected person, Rosamund Lewis, the World Health Organization’s lead on monkeypox, told The Washington Post on Monday.

Monkeypox usually spreads from human to human through direct contact with infectious rashes, scabs or bodily fluids. It can also be transmitted from respiratory secretions during prolonged face-to-face contact, or during intimate physical contact, such as kissing, cuddling or sex.

Monkeypox is ‘a public health emergency,’ U.S. health secretary declares

The potential case of human-to-dog transmission was discovered in a 4-year-old Italian greyhound 12 days after its owners had an onset of monkeypox symptoms, according to the Lancet report.

The dog had lesions on its skin and mucous membranes, pustules on its abdomen and a thin anal ulceration. Medical staffers matched one of the dog owners’ infections to the one detected in the animal.

Researchers said the dog belonged to two men who were in a nonexclusive, cohabiting relationship with each other. One of the partners is a 44-year-old man, and his partner is a 27-year-old man, according to the report.

The couple reported that they let their dog sleep in the bed with them and that they had prevented their pet from being in contact with other humans and pets based on the onset of their own symptoms.

Monkeypox has been roaring through communities of men who have sex with men, increasing anxiety and concern in cities with high populations of gay and bisexual men, and prompting the WHO to advise those groups to limit sexual partners to reduce risk of exposure.

What to know about monkeypox symptoms, treatments and protection

About 99 percent of monkeypox cases worldwide are found in men, and 98 percent of those cases involve men who have sex with men, Lewis said Monday, shortly after the Lancet report surfaced.

Lewis also addressed transmission of the monkeypox virus between humans and animals, sharing that there have been cases of people getting the virus from newly acquired pets.

“This is the first incident that we’re learning about where there is human-to-animal transmission,” she said of the Lancet report’s findings. “So, on a number of levels, this is new information. It’s not surprising information, and it’s something that we’ve been on the watch out for.”

World ignored monkeypox threats, including signs of sexual transmission

In the report, researchers called for further investigation on secondary transmissions via pets.

“Our findings should prompt debate on the need to isolate pets from monkeypox virus-positive individuals,” they said.

Lewis said messaging has encouraged people to isolate their pets from family members who may be infected with monkeypox — a precautionary approach as scientists continue to study the virus’s spread, she said.

“So again, we don’t know if that dog can go and transmit the infection to anyone else, for example,” she said. “This is an example where most pets will not be at risk. It may only be those who are actually in the household of someone who’s infected.”

Rosamund Lewis, MDCM joins Washington Post Live on Monday, Aug. 15. (Video: The Washington Post)

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Corneas made from pig skin restore sight in humans: study – The Hill

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Story at a glance

  • Corneal implants made from pig skin have restored eyesight into 20 people with damaged or diseased corneas, a new study claims. 
  • The cornea is the clear part of the eye that covers the iris and pupil and allows light to enter the eye. Corneal impairments are the fourth leading cause of blindness, according to the WHO.
  • Researchers hope that the study’s findings mean the implants can serve as an alternative to corneal transplants from humans which can be hard to come by, especially in some countries in Asia, Africa and the Middle East. 

Implants made from pig skin have restored sight in the blind, according to a new study.

The implant used in the study replicates the human cornea — the transparent part of the eye that covers the iris and pupil allowing light to enter — and is made from collagen protein found in pigs.  

In the pilot study, published in journal Nature Biotechnology, the implants were able to restore sight in 20 people with damaged or diseased corneas. Fourteen participants were completely blind prior to the procedure.  

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Patients, who lived in India and Iran, had a condition called keratoconus where the cornea gradually becomes thinner and bulges outward.  

After 24 months of receiving the implants, all the patients had improved vision, according to the study.  

The study crafters, a team of researchers from Sweden, India and Iran, hope that the implants could be a replacement for corneal transplants from humans, which can be hard to come by.  

Experts estimate that there are about 12.7 million people who are waiting for donated corneas, with only one cornea available for every 70 people in need of a transplant, the study states.  

Lack of access to donated corneas is even more severe in lower to middle-income countries in Asia, Africa and the Middle East.  

“The results show that it is possible to develop a biomaterial that meets all the criteria for being used as human implants, which can be mass produced and stored up to two years and thereby reach even more people with vision problems,” said Neil Lagali, co-author of the study and professor at Linkoping University in Sweden. 

“This gets us around the problem of shortage of donated corneal tissue and access to other treatments for eye diseases.” 

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Science

How quirk of primate evolution gave humans the voice apes lack | Evolution

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Scientists have identified evolutionary modifications in the voice box distinguishing people from other primates that may underpin a capability indispensable to humankind: speaking.

Researchers said on Thursday that an examination of the voice box, or larynx, in 43 species of primates showed that humans differ from apes and monkeys in lacking an anatomical structure called a vocal membrane: small, ribbon-like extensions of the vocal cords.

Humans also lack balloon-like laryngeal structures called air sacs that may help some apes and monkeys produce loud and resonant calls, and avoid hyperventilating, they found.

The loss of these tissues, according to the researchers, resulted in a stable vocal source in humans that was critical to the evolution of speech – the ability to express thoughts and feelings using articulate sounds.

This simplification of the larynx enabled humans to have excellent pitch control with long and stable speech sounds, they said.

“We argue that the more complicated vocal structures in nonhuman primates can make it difficult to control vibrations with precision,” said primatologist Takeshi Nishimura of Kyoto University’s Centre for the Evolutionary Origins of Human Behaviour in Japan, lead author of the research published in the journal Science.

“Vocal membranes allow other primates to make louder, higher-pitched calls than humans – but they make voice breaks and noisy vocal irregularity more common,” said evolutionary biologist and study co-author W Tecumseh Fitch of the University of Vienna.

The larynx, a hollow tube in the throat that is connected to the top of the windpipe and contains the vocal cords, is used for talking, breathing and swallowing.

“The larynx is the organ of voice, which creates the signal we use to sing and speak,” Fitch said.

Humans are primates, as are monkeys and apes. The evolutionary lineage that led to our species, Homo sapiens, split from the one that led to our closest living relatives, chimpanzees, roughly 6m to 7m years ago, with the laryngeal changes occurring sometime after that.

Only living species were included in the study because these soft tissues are not apt to be preserved in fossils. This also means it is unclear when the changes took place.

Fitch said it is possible the laryngeal simplification arose in a human forerunner called Australopithecus, which combined ape-like and human-like traits and first appeared in Africa roughly 3.85m years ago, or later in our genus Homo, which first appeared in Africa about 2.4m years ago. Homo sapiens originated more than 300,000 years ago in Africa.

The researchers studied laryngeal anatomy in apes including chimpanzees, gorillas, orangutans and gibbons, as well as Old World monkeys including macaques, guenons, baboons and mandrills and New World monkeys including capuchins, tamarins, marmosets and titis.

While this evolutionary simplification of the larynx was pivotal, it “did not give us speech by itself”, Fitch noted, pointing out that other anatomical traits mattered for speech over time, including a change in the position of the larynx.

Sound production mechanisms in people and nonhuman primates are similar, with air from the lungs driving oscillations of the vocal cords. Acoustical energy generated this way then passes through the pharyngeal, oral and nasal cavities and emerges in a form governed by the filtering of specific frequencies dictated by the vocal tract.

“Speech and language are critically related, but not synonymous,” said primatologist and psychologist Harold Gouzoules of Emory University in Atlanta, who wrote a commentary in Science accompanying the study.

“Speech is the audible sound-based manner of language expression – and humans, alone among the primates, can produce it.”

Paradoxically, the increased complexity of human spoken language followed an evolutionary simplification.

“I think it’s pretty interesting that sometimes in evolution ‘less is more’ – that by losing a trait you might open the door to some new adaptations,” Fitch said.

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A Common ‘Forever Chemical’ Has Just Been Linked to Liver Cancer in Humans : ScienceAlert

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A common ‘forever chemical’ known as PFOS (perfluorooctanesulfonic acid) has been linked to liver cancer in humans in a worrying new study.

Once a key ingredient in the water-repelling product commercially known as Scotchguard, PFOS was finally phased out soon after the turn of the century following concerns over its toxicity and environmental impact.

Still, it didn’t earn its label of ‘forever chemical’ for nothing, with environmental levels of this and closely related substances remaining alarmingly high around the globe.

Now a study by researchers from the University of Southern California and the Icahn School of Medicine at Mount Sinai in the US have confirmed an association between PFOS and the development of a particularly deadly form of liver cancer.

Hepatocellular carcinoma (HCC) accounts for more than four out of five cases of liver cancer in the world. With a five-year survival rate of less than 20 percent, it’s also regarded as one of the most deadly of cancers any of us could get.

Although the total incidence of HCC has declined over the past decade in the wake of dropping hepatitis infections, a rise in non-alcoholic fatty liver disease – a condition exacerbated by obesity and high cholesterol – could confound efforts to keep cases down.

On the back of research like this new study, we might also add contaminated drinking water to that list of risk factors.

The long-chains of synthetic compounds known as perfluoroalkyl substances (PFAS) are now widely recognized as particularly nasty saboteurs of our body’s hormonal and liver systems.

In spite of a succession of bans of PFAS in jurisdictions around the globe over recent years, a regrettable amount of damage might already be seeded.

Along with substances like perfluorooctanoate (PFOA), and perfluorohexane sulfonate (PFHxS), PFAS and PFOS take their time breaking down in the environment, with half-lives of up to seven years.

That means in spite of efforts to slowly wind down their production and replace their use in anything from cosmetics to fabric protection to fire-fighting foam, today’s population continues to be exposed to whatever was being dumped into waterways decades ago. And will for some time yet.

With more than 98 percent of the adult US population having detectable concentrations of these compounds in their blood, researchers are now turning their attention to questions of what might be considered a ‘safe’ level of contamination.

Animal studies have demonstrated clear links between PFAS and liver damage. But what was really needed was a population-scale analysis of exposure and risk of ill health.

“Part of the reason there has been few human studies is because you need the right samples,” says Veronica Wendy Setiawan, a cancer epidemiologist from the Keck School of Medicine at the University of Southern California.

“When you are looking at an environmental exposure, you need samples from well before a diagnosis because it takes time for cancer to develop.”

As part of a collaboration with the University of Hawai’i called the Multiethnic Cohort Study, the researchers analyzed blood taken from 50 individuals a diagnosis of non-viral HCC.

These were compared with a carefully matched sample of bloods taken from 50 volunteers without a diagnosis.

Measuring levels of various types of PFAS in blood samples taken prior to the development of liver cancer, the researchers identified a strong association between PFOS and HCC.

Those in the top 10 percent of blood-PFOS levels, in fact, were 4.5 times more likely to develop HCC than those with lower blood-PFOS levels, providing the strongest evidence yet that we’re capable of absorbing dangerous levels of these notorious substances.

“This study fills an important gap in our understanding of the true consequences of exposure to these chemicals,” says the study’s lead author, Keck School of Medicine public health researcher Leda Chatzi.

Knowing where we can draw the line on a safe level of exposure will go a long way to refining regulations and supporting measures on monitoring environmental levels, without resorting to panic or risking the spread of misinformation.

Forever chemicals might be with us for a while to come, but the sooner we can learn just how bad they are, the better off future generations will be.

This research was published in JHEP Reports.

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Langya virus: China discovers potentially fatal new virus passed to humans from shrews

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China has discovered a potentially fatal new virus that is believed to have been passed to humans by shrews, according to reports.

The Langya Henipavirus, known as “Langya,” has already infected 35 people, although no one has died or suffered a serious illness, says Taiwan’s Centers for Disease Control as per a report in The Taipei Times.

The outlet also noted that the virus has so far been found in China’s Shandong and Henan provinces, and human-to-human transmission has not yet been reported.

Twenty-six of the patients have reportedly been hit by flu-like symptoms, including fever, tiredness, cough, headache, and vomiting.

The new virus is in the Henipavirus family, which has two previously identified viruses, the Hendra virus and Nipah virus. There is no vaccine and, in severe cases, it can have a fatality rate of up to 75 per cent, according to the World Health Organization.

The development of the new henipavirus has also appeared in a study titled “A Zoonotic Henipavirus in Febrile Patients in China” which was published in the New England Journal of Medicine last week.

“There was no close contact or common exposure history among the patients, which suggests that the infection in the human population may be sporadic,” the study stated.

The study found that of 25 species of wild small animals tested, the virus was predominantly found in shrews (27 per cent) and stated it was “a finding that suggests that the shrew may be a natural reservoir of LayV.”

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Langya virus: China discovers potentially fatal new virus passed to humans from shrews

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China has discovered a potentially fatal new virus that is believed to have been passed to humans by shrews, according to reports.

The Langya Henipavirus, known as “Langya,” has already infected 35 people, although no one has died or suffered a serious illness, says Taiwan’s Centers for Disease Control as per a report in The Taipei Times.

The outlet also noted that the virus has so far been found in China’s Shandong and Henan provinces, and human-to-human transmission has not yet been reported.

Twenty-six of the patients have reportedly been hit by flu-like symptoms, including fever, tiredness, cough, headache, and vomiting.

The new virus is in the Henipavirus family, which has two previously identified viruses, the Hendra virus and Nipah virus. There is no vaccine and, in severe cases, it can have a fatality rate of up to 75 per cent, according to the World Health Organization.

The development of the new henipavirus has also appeared in a study titled “A Zoonotic Henipavirus in Febrile Patients in China” which was published in the New England Journal of Medicine last week.

“There was no close contact or common exposure history among the patients, which suggests that the infection in the human population may be sporadic,” the study stated.

The study found that of 25 species of wild small animals tested, the virus was predominantly found in shrews (27 per cent) and stated it was “a finding that suggests that the shrew may be a natural reservoir of LayV.”

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Science

Discovery in paleontologist’s backyard reveals evidence of North America’s early humans

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Butchering marks can be seen on the mammoth ribs. The top rib shows a fracture from blunt force impact, the middle rib shows a puncture wound and the bottom rib shows chopping marks. (Timothy Rowe et al., The University of Texas at Austin)

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AUSTIN, Texas — The surprising discovery of mammoth fossils in a paleontologist’s backyard have led to an even more unexpected finding.

The roughly 37,000-year-old remains of a female mammoth and her calf show distinct signs of butchering, providing new evidence that humans may have arrived in North America much earlier than believed.

Paleontologist Timothy Rowe first learned of the fossils in 2013 when a neighbor noticed something sticking out of a hillside on some New Mexico property belonging to Rowe.

Upon closer inspection, Rowe found a tusk, a bashed-in mammoth skull and other bones that looked deliberately broken. He believed it was the site where two mammoths had been butchered.

“What we’ve got is amazing,” Rowe said in a statement. “It’s not a charismatic site with a beautiful skeleton laid out on its side. It’s all busted up. But that’s what the story is.”

Rowe, a professor at the University of Texas at Austin’s Jackson School of Geosciences, is an expert in vertebrate paleontology and doesn’t typically study mammoths or early humans. But he couldn’t help but work on the research due to the discovery’s location.

Two six-week excavations took place at the site in 2015 and 2016, but analysis in the lab has taken much longer and remains ongoing, Rowe said. He is the lead author of a new study providing an analysis of the site and its implications, which was published in the journal Frontiers in Ecology and Evolution in July.

What we’ve got is amazing. It’s not a charismatic site with a beautiful skeleton laid out on its side. It’s all busted up. But that’s what the story is.

–Timothy Rowe, paleontologist

“I have yet to fully process the cosmic coincidence of this site appearing in my backyard,” Rowe wrote in an email.

Analyzing the site

Multiple finds at the site paint a portrait of what took place there thousands of years ago, including bone tools, evidence of a fire, bones bearing fractures and other signs of animal butchering by humans.

Long mammoth bones shaped into disposable blades were used to break down the animal carcasses before a fire helped melt down their fat.

Fractures created by blunt force can be seen in the bones, according to the study. No stone tools were at the site, but researchers found flake knives made from bones with worn edges.

A chemical analysis of the sediment around the mammoth bones showed that the fire was sustained and controlled rather than caused by a wildfire or lightning strike. There was also evidence of bone that had been pulverized as well as burned small animal remains, including birds, fish, rodents and lizards.

Close up of the bone pile during excavation. This random mix of ribs, broken cranial bones, a molar, bone fragments, and stone cobbles is a refuse pile from the butchered mammoths. It was preserved beneath the adult mammoth’s skull and tusks. (Photo: Timothy Rowe, University of Texas at Austin)

The research team used CT scans to analyze the bones from the site, finding puncture wounds that would have been used to drain fat from ribs and vertebrae. The humans who butchered the mammoths were thorough, Rowe said.

“I have excavated dinosaurs that were scavenged, but the pattern of bone disarticulation and breakage from human butchering was unlike anything I had seen,” Rowe said.

The most surprising detail about the site is that it’s in New Mexico — and previous evidence has suggested that humans weren’t there until tens of thousands of years later.

Retracing early human steps

Collagen taken from the mammoth bones helped the researchers determine that the animals were butchered at the site between 36,250 and 38,900 years ago. This age range makes the New Mexico site one of the oldest that ancient humans created in North America, researchers said.

Scientists have debated for years about when early humans first arrived in North America.

A recent study on the butchered remains of a mother and baby mammoth shows that humans lived in North America tens of thousands of years earlier than conventionally thought. (Photo: National Park Service)

The 16,000-year-old Clovis culture is known because of the stone tools it left behind. But an increasing amount of evidence suggests that older North American sites were home to a pre-Clovis population that had a different genetic lineage. The older sites have a different kind of evidence, such as preserved footprints, bone tools or animal bones bearing cut marks older than 16,000 years ago.

“Humans have been in the Americas for more than twice as long as archaeologists have maintained for many years,” Rowe said. “This site indicates that humans attained a global distribution far earlier than previously understood.”

This site indicates that humans attained a global distribution far earlier than previously understood.

–Timothy Rowe, paleontologist

The position of the site, which is well within North America’s western interior, suggests that the first humans arrived well before 37,000 years ago, according to the study. These early humans likely traveled over land or along coastal routes.

Rowe said he wants to sample the site to look for signs of ancient DNA next.

“Tim has done excellent and thorough work that represents frontier research,” retired Texas State University professor Mike Collins said in a release. “It’s forging a path that others can learn from and follow.”

Collins was not involved with the study. He led research at the Gault archaeological site, which contains both Clovis and pre-Clovis artifacts, near Austin, Texas.

“I think the deeper meaning of early human attainment of a global distribution is an important new question to explore,” Rowe said. “Our new techniques provided nuanced evidence of a human presence in the archaeological record, and I suspect that there are other sites of comparable age or even older that have gone unrecognized.”

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Science

New Mexico mammoths among best evidence for early humans in North America – HeritageDaily

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Bones from a mammoth butchering site record how humans shaped pieces of their long bones into disposable blades to break down their carcasses, and rendered their fat over a fire.

But, a key detail sets this site apart from others from this era. It’s in New Mexico – a place where most archaeological evidence places the first human activity tens of thousands of years later.

A recent study led by scientists with The University of Texas at Austin suggests that the site offers some of the most conclusive evidence for humans settling in North America much earlier than conventionally thought.

 

The researchers revealed a wealth of evidence rarely found in one place. It includes fossils with blunt-force fractures, bone flake knives with worn edges, and signs of controlled fire. And thanks to carbon dating analysis on collagen extracted from the mammoth bones, the site also comes with a settled age of 36,250 to 38,900 years old, making it among the oldest known sites left behind by ancient humans in North America.

“What we’ve got is amazing,” said lead author Timothy Rowe, a palaeontologist and a professor in the UT Jackson School of Geosciences. “It’s not a charismatic site with a beautiful skeleton laid out on its side. It’s all busted up. But that’s what the story is.”

Rowe does not usually research mammoths or humans. He got involved because the bones showed up in his backyard, literally. A neighbour spotted a tusk weathering from a hillslope on Rowe’s New Mexico property in 2013. When Rowe went to investigate, he found a bashed-in mammoth skull and other bones that looked deliberately broken. It appeared to be a butchering site. But suspected early human sites are shrouded in uncertainty. It can be notoriously difficult to determine what was shaped by nature versus human hands.

This uncertainty has led to debate in the anthropological community about when humans first arrived in North America.

 

Although the mammoth site lacks clearly associated stone tools, Rowe and his co-authors discovered an array of supporting evidence by putting samples from the site through scientific analyses in the lab.

Among other finds, CT scans taken by the University of Texas High-Resolution X-ray Computed Tomography Facility revealed bone flakes with microscopic fracture networks akin to those in freshly knapped cow bones and well-placed puncture wounds that would have helped in draining grease from ribs and vertebral bones.

“There really are only a couple efficient ways to skin a cat, so to speak,” Rowe said. “The butchering patterns are quite characteristic.”

In addition, chemical analysis of the sediment surrounding the bones showed that fire particles came from a sustained and controlled burn, not a lightning strike or wildfire. The material also contained pulverized bone and the burned remains of small animals – mostly fish (even though the site is over 200 feet above the nearest river), but also birds, rodents and lizards.

Based on genetic evidence from Indigenous populations in South and Central America and artefacts from other archaeological sites, some scientists have proposed that North America had at least two founding populations: the Clovis and a pre-Clovis society with a different genetic lineage.

The researchers suggest that New Mexico site, with its age and bone tools instead of elaborate stone technology, may lend support to this theory. Collins said the study adds to a growing body of evidence for pre-Clovis societies in North America while providing a toolkit that can help others find evidence that may have been otherwise overlooked.

“Tim has done excellent and thorough work that represents frontier research,” Collins said. “It’s forging a path that others can learn from and follow.”

Co-authors include Jackson School professor Richard Ketcham and research scientists Romy Hanna and Matthew Colbert, as well as scientists from the Gault School of Archaeological Research, the University of Michigan, Aarhus University, and Stafford Research.

The University of Texas at Austin

Header Image Credit: Timothy Rowe / The University of Texas at Austin

 

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