'Viking' was likely a job title among diverse people, says DNA study
"The results change the perception of who a Viking actually was," said project leader Professor Eske Willerslev.
17 September, 2020
Västergötlands Museum
- A team of international researchers spent years analyzing the DNA of 442 people, most of whom lived during the Viking age.
- It's the largest DNA analysis of Viking remains to date.
- The results show that Vikings were more genetically diverse than previously thought.
<p>In the late 8th century, a seafaring people from modern-day Scandinavia began to earn the name <em>víkingr</em>, which meant "pirate" in early Scandinavian languages.<br></p>
<p>Today, Vikings are often thought of as barbaric blonde-haired invaders who violently changed the course of European history. And that's mostly true: Vikings were cruel and skilled warriors, innovative shipwrights, and they not only colonized many parts of Europe, but also became the first Europeans to settle in North America. </p>
<p>But a new study published in <a href="https://www.nature.com/articles/s41586-020-2688-8" target="_blank" rel="noopener noreferrer">Nature</a> offers a more nuanced understanding of the Vikings, suggesting they were more genetically diverse than previously imagined. For the study, an international team of researchers examined the DNA of 442 people who lived from roughly 2,400 B.C. to 1,600 A.D. The remains were collected from Viking burial sites, and most dated back to the Viking Age from roughly 800 to the 1050s.</p>
<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDQyMTQ4MC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYyODU1OTc2M30.SVafazLuFStjdgXAQofRvqv4sSsVNy9j9Xp9xC7EFFk/img.jpg?width=980" id="89116" class="rm-shortcode" data-rm-shortcode-id="dc3270f61f18230efc1e3e696ba0f5c5" data-rm-shortcode-name="rebelmouse-image" alt="Vikings" />
An artistic reconstruction of 'Southern European' Vikings emphasising the foreign gene flow into Viking Age Scandinavia.
Credit: Jim Lyngvild
<p>The results deal a blow to our modern image of Vikings.</p><p style="margin-left: 20px;">"We didn't know genetically what they actually looked like until now," project leader Professor Eske Willerslev, director of The Lundbeck Foundation GeoGenetics Centre, University of Copenhagen, said in a <a href="https://www.eurekalert.org/pub_releases/2020-09/sjcu-wld091120.php" target="_blank">statement</a>. "We found genetic differences between different Viking populations within Scandinavia which shows Viking groups in the region were far more isolated than previously believed. Our research even debunks the modern image of Vikings with blonde hair as many had brown hair and were influenced by genetic influx from the outside of Scandinavia."</p><img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDQyMTQ4Mi9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY1MjQxNDIyMH0.h08BKRDY-xbUvk7UrRCJJL7yQr5DhqHvxBXXu64oyGs/img.jpg?width=980" id="2c993" class="rm-shortcode" data-rm-shortcode-id="27a0567762ba3b937d59fa0d0747dc01" data-rm-shortcode-name="rebelmouse-image" alt="Viking burial" />
A mass grave of around 50 headless Vikings from a site in Dorset, UK. Some of these remains were used for DNA analysis.
<p>Part of that genetic influx came from afar. The team's genetic analysis — which is the most comprehensive ever conducted on Viking remains — revealed influences from Southern Europe and Asia. For example, some Viking remains showed influences of mixed European and Sami heritage. (Known for reindeer herding throughout Scandinavia, the Sami people <a href="https://www.nature.com/articles/ejhg200888" target="_blank">share some genetic links with Asian populations</a>.)</p><p>Findings like these suggest the Vikings might have had less hostile interactions with some groups than previously thought.</p><p style="margin-left: 20px;">"We have this image of well-connected Vikings mixing with each other, trading and going on raiding parties to fight Kings across Europe because this is what we see on television and read in books - but genetically we have shown for the first time that it wasn't that kind of world," Willerslev said. "This study changes the perception of who a Viking actually was — no one could have predicted these significant gene flows into Scandinavia from Southern Europe and Asia happened before and during the Viking Age."</p>Redefining the 'Viking' identity
<p>What's more, some of the people who received Viking burials weren't genetically related to the Vikings, suggesting the term "Viking" might have referred more to a job description or cultural identity rather than genetic heritage.</p><p style="margin-left: 20px;">"Importantly our results show that 'Viking' identity was not limited to people with Scandinavian genetic ancestry," study co-author Søren Sindbæk, an archaeologist from Moesgaard Museum in Denmark, said in a <a href="https://www.eurekalert.org/pub_releases/2020-09/sjcu-wld091120.php" target="_blank">statement</a>. "Two Orkney skeletons who were buried with Viking swords in Viking style graves are genetically similar to present-day Irish and Scottish people and could be the earliest Pictish genomes ever studied."</p><p>Although Vikings idolized warrior culture, took slaves, and focused much of their energy on conquering Europe, they also <a href="https://www.historyonthenet.com/vikings-as-traders" target="_blank" rel="noopener noreferrer">helped expand trade throughout the continent</a>, developed <a href="http://www.sourcinginnovation.com/archaeology/Arch07.htm" target="_blank" rel="noopener noreferrer">innovative farming and crafting techniques</a>, and were <a href="https://www.bbc.com/news/uk-scotland-46194699" target="_blank" rel="noopener noreferrer">relatively egalitarian in terms of women's rights</a>. Using a genetic framework, the new study adds a deeper layer to history's understanding of the Vikings.</p><p style="margin-left: 20px;">"The results change the perception of who a Viking actually was," Willerslev said in the statement. "The history books will need to be updated."</p>
Keep reading
Show less
Are mental health disorders ever purely biological?
Two anthropologists question the chemical imbalance theory of mental health disorders.
26 August, 2020
- Two physical anthropologists argue that you cannot pin most mental health disorders on brain chemistry alone.
- As antidepressants will soon be a $16B industry, the chemical imbalance theory suits business interests better than health interests.
- An etiology of depression should include behavioral observation, cross-population comparisons, cultural transmission, and evolutionary theory.
<p><br></p>
<p>Twentieth-century science was supposed to change everything. Indeed, thanks to vaccinations, antibiotics, and improved sanitation, humans thrived like never before. Yet in that mix was thrown pharmacological treatments for mental health disorders. On that front, little progress has been made.</p><p>It can be argued—it <em>is</em> being argued, in a <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/ajpa.23965" target="_blank">new paper</a> in American Journal of Physical Anthropology—that we're regressing in our fight against mental health problems. As Kristen Syme, a PhD student in Evolutionary Anthropology, and Washington State University anthropology professor Edward Hagen argue, psychopharmacological treatments are increasing alongside mental health disorder diagnoses. If the former worked, the latter would decrease. </p><p>There are numerous problems with the current psychiatric model. Journalist Robert Whitaker has <a href="https://bigthink.com/mind-brain/antidepressants-dangers" target="_self" rel="dofollow">laid out the case</a> that antidepressants, antipsychotics, and other pharmacological interventions are the real culprit behind chemical imbalances in the brain—a psychiatric talking point that's <a href="https://bigthink.com/mind-brain/chemical-imbalance" target="_self">been challenged</a> for over a half-century. Patients suffering from minor anxiety and depression are placed on <a href="https://bigthink.com/surprising-science/antidepressant-effects" target="_self" rel="dofollow">ineffective drugs</a>, often being placed on a cocktail of pills. With many consumer advocacy groups being <a href="https://bigthink.com/politics-current-affairs/pharma-lobbying" target="_self">funded by pharmaceutical companies</a>, we've reached a tipping point in mental health protocols. </p><p>As Syme and Hagan write, consumer advocacy groups are not the only compromised organizations. One <a href="https://pubmed.ncbi.nlm.nih.gov/16199844/" target="_blank">review</a> of 397 clinical trials discovered 47 percent of these studies reported at least one conflict of interest. As Whitaker has <a href="https://bookshop.org/books/anatomy-of-an-epidemic-magic-bullets-psychiatric-drugs-and-the-astonishing-rise-of-mental-illness-in-america/9780307452429" target="_blank" rel="noopener noreferrer dofollow">written about</a> before, when pharmaceutical companies don't like the results of their trials, they're scrapped until more suitable results are recorded. </p><p>Humans proliferated as never before during the last century, yet technological innovation does not always equate to better outcomes. We live by a perpetual illusion of progress. Severing ties with nature has had profound consequences on our health. This drives to the heart of Syme and Hagan's paper: brain chemistry is heavily influenced by society. Sure, some people are born with genetic-based developmental dysfunctions. This doesn't account for increasing numbers of people on Zoloft and Xanax and dozens of other medications today. </p>
EarthRise 91: Do antidepressants create more mental illness than they cure? (with Robert Whitaker)
<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="8f49b126e8733bbd95c21de0476fb1f8"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/UnB7tXvztT4?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p>Physical anthropology and evolutionary biology are essential fields of study when contemplating all facets of health. Historical perspective is important. The authors point to a previous battle: in 1900, roughly half of all deaths in the U.S. were attributed to infectious diseases. A century later, the number of deaths due to such diseases was negligible. </p><p>That's because the etiologies of a number of infectious diseases were discovered thanks to <a href="https://en.wikipedia.org/wiki/Germ_theory_of_disease" target="_blank">germ theory</a>. There has never been a holistic etiology of anxiety or depression, however. Psychiatrists, in coordination with pharmaceutical companies, exploited that fact by creating and marketing a singular etiology—the chemical imbalance theory—and selling the world on pharmacology.</p><p>Think about the basic framework of this proposition: an animal that has evolved for millions of years, roughly 350,000 in the present form, experiences its greatest century to date in terms of population expansion, while simultaneously billions of our brains are suddenly chemically compromised. This narrative boggles the mind, yet it's exactly what's being sold by psychiatrists and medical doctors around the world. </p><p>As the authors write, the chemical imbalance theory, first widely discussed in the late forties, became part of a public health campaign designed to destigmatize mental health issues in the aughts. In reality, the campaign accomplished the opposite. </p><p style="margin-left: 20px;">"First, a systematic review found that an endorsement of biogenetic causes of mental disorders does not reduce stigma and, in fact, might even increase stigmatizing attitudes among mental health professionals and the mentally ill themselves. Second, there is little evidence that psychopharmaceuticals correct specific chemical imbalances or neurobiological deficits."</p><p>While mental health is a broad term with numerous categories, the authors divide disorders into <a href="https://www.madinamerica.com/2020/08/anthropologists-question-legitimacy-mental-disorders/" target="_blank">four subsets</a>: </p><ul><li>Disorders which are genetic-based developmental dysfunctions</li><li>Disorders associated with senescence/aging</li><li>Disorders caused by a mismatch between modern and ancestral environments</li><li>Disorders which are adaptive responses to adversity, however undesirable</li></ul><img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzU4MjIwOS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYwNzg2Njc5NX0.9HRqkOB3VPX9RThKJi_bSbOeWAlZhy-MQYXKp1UnXQY/img.jpg?width=1245&coordinates=0%2C598%2C0%2C144&height=700" id="72bc9" class="rm-shortcode" data-rm-shortcode-id="e0f87a0af4791d0dd3426d78e4db0593" data-rm-shortcode-name="rebelmouse-image" />
Photo: Everett Collection / Shutterstock
<p>The first two account for many common diseases, such as dementia, autism, and schizophrenia. The second pair represent disorders that modern psychiatry has exploited. By failing to consider environmental, racial, economic, familial, and societal forces, we've been sold a story that we're broken from birth. </p><p>This story serves a purpose: the global antidepressant industry is <a href="https://www.prnewswire.com/news-releases/antidepressant-drugs-market-to-reach-15-98-bn-by-2023-globally-at-2-1-cagr-says-allied-market-research-873540700.html" target="_blank" rel="noopener noreferrer dofollow">expected to reach</a> $16B by 2023. Thanks to concerted marketing and lobbying efforts, an uptick in prescriptions coincides with an increasing number of disorders—and increasing numbers of children on these drugs. When one market is exploited, create another. </p><p>Pharmacological interventions for Parkinson's, Alzheimer's, and autism might be valuable to patients of these disorders. The problem isn't with drug development, which is a necessary field of research for combating such confounding diseases. As has long been known—since at least the 19th century, though likely much longer—most anxiety and depression alleviates with time, especially when interventions such as <a href="https://bigthink.com/21st-century-spirituality/your-diet-might-be-causing-anxiety-and-depression" target="_self">proper diet</a>, <a href="https://bigthink.com/surprising-science/exercise-mental-health" target="_self" rel="dofollow">exercise</a>, and <a href="https://bigthink.com/mind-brain/depression-universal-basic-income" target="_self">improved economic conditions</a> are put into place. As Syme and Hagan conclude, </p><p style="margin-left: 20px;">"A final group of disorders, such as anxiety, depression, and PTSD, have low heritability, are caused by adversity, and involve symptoms that seem to be adaptive responses to adversity. Because they are relatively common throughout adult life, they account for a substantial fraction of disease burden attributable to mental illness. These might not be disorders at all, however, but instead aversive yet adaptive responses to adversity."</p><p>That is, anxiety and depression are largely social problems, not medical disorders. The authors write that it would be unethical to prescribe pain medication for a broken bone without first setting the bone. Why then do psychiatrists and doctors churn out scripts without identifying the source of suffering that brought the patient into the office in the first place?</p><p>Though we don't yet have reliable etiologies of most mental health disorders, the authors conclude that they could be within reach. Their discovery relies not on brain chemistry alone, but on epigenetics, behavioral observation, cross-population comparisons, cultural transmission, evolutionary theory, and much more. </p><p>Humans are complex animals. Perhaps Occam's razor isn't as sharp as we believe.</p><p>--</p><p><em>Stay in touch with Derek on <a href="http://www.twitter.com/derekberes" target="_blank">Twitter</a>, <a href="https://www.facebook.com/DerekBeresdotcom" target="_blank">Facebook</a> and <a href="https://derekberes.substack.com/" target="_blank" rel="noopener noreferrer dofollow">Substack</a>. His next book is</em> "<em>Hero's Dose: The Case For Psychedelics in Ritual and Therapy."</em></p>
Keep reading
Show less
Why are there so many humans?
Having lots of kids is great for the success of the species. But there's a hitch.
03 August, 2020
Photo by chuttersnap on Unsplash
Something curious happened in human population history over the last 1 million years.
<p> First, our numbers fell to <a href="https://www.pnas.org/content/107/5/2147" target="_blank">as low as 18,500</a>, and our ancestors were more endangered than chimpanzees and gorillas. Then we bounced back to extraordinary levels, far surpassing the other great apes.
</p><p>
Today the total population of gorillas, chimpanzees, bonobos, and orangutans is estimated to be only around 500,000, according to the <a href="https://wwf.panda.org/knowledge_hub/endangered_species/great_apes/" target="_blank">World Wildlife Fund</a>. Many species are critically endangered. Meanwhile, the human population <a href="https://www.un.org/development/desa/en/news/population/world-population-prospects-2019.html" target="_blank">has surged to 7.7 billion</a>. And the irony is: Our astonishing ability to multiply now threatens the long-term sustainability of many species, including ours.
</p><p>
What happened? Why do we live in the Anthropocene and not a world resembling <a href="http://www.planetoftheapes.com/" target="_blank">Planet of the Apes</a>? We share around 99 percent of our DNA with our great ape cousins, chimpanzees and bonobos. So, what makes us different from our closest relatives that gives us our staggering capacity for reproducing and surviving?
</p><p>
As an evolutionary anthropologist, these questions have led me to live and study among the Yucatec Maya of Mexico, the Pumé hunter-gatherers of Venezuela, and the Tanala agriculturalists of Madagascar. My research,<a href="#note">*</a> combined with genetic data and other studies, offers clues to what developed in the deep past that has made humans so successful—for better or for worse.
</p>
<p>In the 1970s, the isolated village of Xculoc, in Mexico's Yucatan Peninsula, was home to about 300 Maya people. The maize-farming residents had no electricity or running water. Women hauled water from a 50-meter-deep well using ropes and buckets. They ground maize—the mainstay of their diet—in hand-cranked grinders.</p><p>Then two technologies were introduced that changed these Maya's lives and, ultimately, their population: a gas-powered water pump and two gas-powered maize grinders.</p><p>Using these devices, young women saved about two and a half hours of labor and 325 calories a day. In addition, younger siblings could more easily fetch water and crush maize, freeing up their older sisters' time and literally decreasing their daily grind. That's important because studies have found that heavy subsistence work <a href="https://www.jstor.org/stable/10.1086/499550?read-now=1&seq=3#page_scan_tab_contents" target="_blank">suppresses ovarian function</a>, whereas reducing labor and raising women's energy balance is associated with a bump in fertility.</p>
<p>Subsequently, the age at which women in Xculoc first gave birth dropped by two years. And according to my long-term research, women who started childbearing after these machines arrived produced significantly larger families than prior generations. By 2003, women who started reproducing in the 1970s had eight to 12 children.</p><p>Saving women time and energy is central to increasing the population. And humans have developed numerous technological and social ways of accomplishing this that differ from our great ape relatives.</p><p>It's important to note that scientists must be cautious about drawing direct analogies between contemporary people or apes and our ancient ancestors. But modern humans and primates are our best tools for inferring how the underpinnings of our numerical success may have evolved.</p><p>Somewhere along the evolutionary road, humans started to favor new ways of having and raising their young. Mothers began weaning their infants earlier. In modern societies where infants rely on their mother's milk and not bottle feeding, babies nurse for two to three years. By contrast, great ape mothers nurse their young for four to six years.</p><p>Breastfeeding is calorically expensive. It takes a mother about 600 extra calories a day to produce milk. So, the sooner she stops nursing, the sooner she can biologically support another pregnancy. In modern societies without contraception, mothers give birth on average every three years. Other great apes may wait as many as six to eight years between births.</p>
<p>Our ancient ancestors also fed, sheltered, and cared for youngsters who were weaned but still growing. This gave them a better chance at surviving than nonhuman great ape young, which fend for themselves after they're weaned. Today a child living in a hunter-gatherer society is twice as likely as a wild chimpanzee to survive to age 15.</p><p>Novel ways of parenting, compared to earlier hominins, meant human mothers were in the unique situation of having multiple dependents of different ages to care for at the same time. I cannot underscore enough how much this sets human mothers and children apart from the other great apes.</p><p>Having lots of kids is great for the success of the species. But there's a hitch. Mothers don't have enough hours in the day to care for their babies full time while providing for their older offspring. That's especially true because the unique aspects of the human diet give mothers a lot of tasks to juggle</p><p>When these ancient life history traits were evolving, our ancestors made their living as hunter-gatherers, who typically eat diverse fare, including fruits, nuts, tubers, roots, large and small game, birds, reptiles, eggs, insects, fish, and shellfish. Cobbling together such a menu requires modern hunter-gatherers to travel, on average, 13 kilometers per day. By contrast, chimpanzees and gorillas roam, on average, 2 kilometers per day.</p>
<p>What's more, hunter-gatherers process most of their food to make it more digestible or to boost the bioavailability of nutrients. And as everyone who prepares food knows, that takes a significant amount of time.</p><p>Among the Pumé hunter-gatherers from the savannas of Venezuela, women spend about three hours a day cracking, mashing, grinding, pounding, sifting, winnowing, butchering, and cooking food. The same is true of Efe women—hunter-gatherers living in the Ituri forest of Central Africa.</p><p>That prep time is in addition to the hours the Pumé and Efe spend foraging and then carrying ingredients back to camp. Furthermore, each processing task requires a specialized technology, which means someone has to collect raw materials and make tools. !Kung women and men in the Kalahari Desert of Southern Africa spend about an hour each day making and repairing tools. Savanna Pumé women devote nearly two hours to toolmaking—twice as much as the men.</p><p>Hunter-gatherers also build shelters and hearths to provide a safe place to process ingredients, to store food and tools, and to leave children who may be too young to accompany others on long foraging trips. Plus, they must haul water, chop firewood, fashion clothing, and maintain the social and information networks needed to access geographically dispersed resources.</p>
<p>There are simply not enough hours in the day for any one person to accomplish all this. So, our ancestors came up with a solution.</p><p>That solution was cooperation—but not the kind of task-sharing many species engage in. Hunter-gatherers developed a distinct feature called intergenerational cooperation: Parents help kids, <em>and</em> children help parents.</p><p>This is not a trait we share with the other great apes, who aren't particularly good at sharing food, helping mothers or offspring who aren't their own, or even supporting their own children after they reach a certain age. Nonhuman great ape mothers rarely share meals with their juvenile offspring once they're weaned, and juvenile apes don't offer food to their moms.</p><p>But among humans, intergenerational cooperation means it really does take a village to raise a child. Across cultures, mothers in hunter-gatherer and agricultural societies offer only about half of the direct care an infant receives. Savanna Pumé infants, for example, have an average of nine caretakers besides their mother. Efe infants have an average of 11.</p><p>Fathers and grandparents certainly play important roles in supporting their families. But it's not enough. An average Maya mother is 60 by the time her last child leaves home, so she has very few years after that to be a babysitting or food-collecting grandmother.</p><p>My research suggests a much more obvious source of help has been overlooked: kids. Other than mothers, children provide most of the child care in many cultures. And 7- to 10-year-olds do the bulk of the babysitting.</p><p>Children are also responsible for processing much of the food and running the household. A Pumé boy carries home an average of 4.5 kilograms of wild fruit on days he forages. That's the equivalent of 3,200 calories—enough to feed himself and at least some of his family. (And that's in addition to any snacking he does in the field.) His sister can bring home more than a kilogram of roots (worth about 4,000 calories)—some of which she will eat, but most of which she shares. Among the Hadza hunter-gatherers of East Africa, children forage for five to six hours a day. By age 5, they can supply about 50 percent of their own calories during some seasons.</p>
<p>Children in agricultural communities are also hard workers. Yucatec Maya between the ages of 7 and 14 devote two to five hours a day to domestic and field work. Teens between the ages of 15 and 18 labor about 6.5 hours a day—as much as their parents.</p><p>By the time a Maya mother is 40, she has an average of seven children at home. These children contribute a combined 20 hours of work a day and supply 60 percent of what the family consumes.</p><p>Thanks to this multigenerational help, a woman can spend time doing what only she can do: have more children. So, children increase the population, but their labor is also a built-in engine to fuel their community's fertility and speed up reproduction.</p><p>With intergenerational cooperation and a diversity of dietary strategies, our ancestors multiplied and weathered population bottlenecks. Just after 1800, the human population hit 1 billion.</p><p>The global population then expanded exponentially, largely due to the enhanced survival of both infants and older people. It reached 2 billion in 1927, 3 billion in 1960, 4 billion in 1974, 5 billion in 1987, 6 billion in 1999, 7 billion in 2011, and today is at over 7.7 billion.<br><a target="_blank"></a><br>These figures intrigue me as an evolutionary enigma and deeply concern me as a contemporary issue. There is no question, though, that humans have been incredibly successful. The question is: How long can we maintain that success and still be sustainable? The answer, like our secret to growth in the past, stands on the shoulders of cooperation.</p><p><em>* Editor's note: The author derived much of this essay from </em><em>her 47th JAR Distinguished Lecture, "How There Got to Be So Many of Us," which was published in the Winter 2019 issue of the </em>Journal of Anthropological Research<em>.</em></p><p>This work first appeared on <a href="https://www.sapiens.org/" target="_blank">SAPIENS</a> under a <a href="https://creativecommons.org/licenses/by-nd/4.0/" target="_blank">CC BY-ND 4.0 license</a>. Read the <a href="https://www.sapiens.org/evolution/human-population-evolution/" target="_blank">original here</a>.<img src="https://www.sapiens.org/track/12597-1596466362813/?dt=Why+Are+There+So+Many+Humans%3F&dl=https%3A%2F%2Fwww.sapiens.org%2Fevolution%2Fhuman-population-evolution%2F" alt=""><span></span></p>
Keep reading
Show less
48,000-year-old bone arrowheads and jewelry discovered in Sri Lankan cave
Artifacts uncovered in southeast Asia offer clues on early complex human cultures.
23 June, 2020
Langley et al., 2020
- Archaeologists discovered a trove of bone tools used roughly 48,000 years ago in a Sri Lankan cave.
- Uncovered artifacts include the earliest known bow-and-arrow devices found out of Africa, weaving utensils, and decorative beads chiseled from the tips of marine snail shells.
- The findings underline the necessity of looking for early Homo sapien innovation in regions outside of the grasslands and coasts of Africa or Europe, where much of the research has been focused.
<p>A group of archaeologists have discovered a remarkable trove of bone tools used roughly 48,000 years ago in a Sri Lankan cave, according to new research published in the journal <a href="https://advances.sciencemag.org/content/6/24/eaba3831" target="_blank">Science Advances</a>.</p>
New discoveries
<p>The study was led by Michelle Langley, an archaeologist at Australia's Griffith University, along with other researchers from Griffith, Max Planck Institute for the Science of Human History (MPI-SHH), and the Sri Lankan Government's Department of Archaeology.</p><p>The scientists examined tools and artifacts used between 48,000 and 4,000 years ago that were discovered in the Fa-Hien Lena cave site located in Sri Lanka's southwest tropical forests, an area that has become one of the most important archaeological sites in South Asia since the 1980s. The assemblage of artifacts included 130 of the earliest known bone-arrow tips found out of Africa along with 29 utensils likely used to make clothing or bags. Also excavated were decorative beads chiseled from the tips of marine snail shells and the world's oldest known beads made of red ochre — an ancient pigment used for a variety of things from body paint to sunscreen.</p><p>Archaeologists believe that these tools correspond to four phases of ancient human habitation of the site. Using radiocarbon technology to date thirty items from the site, researchers were able to create a timeline detailing how the tools evolved to become more sophisticated over time.</p><p>"Most of these tools were made out of monkey bone, and many of them appear to have been carefully shaped into arrowheads," <a href="https://experts.griffith.edu.au/8914-michelle-langley" target="_blank">Langley</a> told Tim Vernimmen of <a href="https://www.nationalgeographic.com/science/2020/06/tools-human-early-migration-rainforest-sri-lanka/" target="_blank">National Geographic</a>. "They are too small and light to have been spearheads, which need some weight to gain force, and too heavy and blunt to have been blow darts."</p><p>On close inspection, the size, forms and fractures found on many of the bone points led the researchers to believe that they were used as arrow tips for bow-and-arrow hunting to catch swift and nimble rainforest prey like monkeys and other tree-dwelling creatures. The arrow points increased in length over time for the purpose of hunting larger mammals like deer. If the researcher's conclusions are correct, this finding marks the earliest definitive proof of high-powered projectile hunting in a tropical rainforest environment.</p><p>Additionally, the team uncovered a range of other bone and tooth tools used for scraping and piercing. They were likely used for making nets and working animal skins or plant fibers in the tropical environment.</p><p>"Evidence for the construction of nets is extremely scarce in artifacts many thousands of years old, making this aspect of the Fa-Hien Lena assemblage a startling find," Langley said in <a href="https://news.griffith.edu.au/2020/06/15/discovery-of-oldest-bow-and-arrow-technology-outside-africa/" target="_blank">a Griffith University press release</a>. Because this wasn't a cold region, the authors opine that the clothing made with the assemblage of tools may have been used for protection from insect-borne diseases.</p><p>Other tools discovered at the site were identified as implements probably associated with freshwater fishing.</p>Out of Africa and into the rainforest
<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzQxMDExMS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY1NTQ3NjQ4N30.6JVTKeCHRhzvg5lejtnsxf-2y0n1pHAch0MrxJSre1Y/img.jpg?width=980" id="56032" class="rm-shortcode" data-rm-shortcode-id="8a86a57e2bb25a4caa3d1777fbcd060b" data-rm-shortcode-name="rebelmouse-image" alt="assortment of bone arrowheads and tools" />"Bone projectile points (A to H) and scrapers (I to K) from Fa-Hien Lena. (A and B) Geometric bipoints, with (B) coming from phase D context 146; (C and F) hilted bipoint, red arrows indicate cut notches; (D and E) hilted unipoints, red arrows and red circle indicate wear indicating fixed hafting; (G and H) symmetrical bipoints"
Langley et al., 2020
<p>Before the great migration out of Africa, smaller groups of humans began to leave the continent between 200,000 and 100,000 years ago eventually migrating into South Asia. These findings offer clues as to how our ancient ancestors adapted to diverse, precarious environments during their global expansion, such as the tropical rainforest. Though the early humans of South Asia likely didn't make their abode in the densely vegetated forest right away, opting instead for the coast, their decedents eventually would. And that move required some nifty new survival technology. </p><p>The researchers pointed out that their discoveries of these ancient tools underline the necessity of looking for early <em>Homo sapien</em> innovation in regions outside of the grasslands and coasts of Africa, or Europe where much of the research has been focused.</p><p>"[T]his traditional focus has meant that other parts of Africa, Asia, Australasia and the Americas have often been sidelined in discussions of the origins of material culture, such as novel projectile hunting methods or cultural innovations associated with our species," <a href="https://news.griffith.edu.au/2020/06/15/discovery-of-oldest-bow-and-arrow-technology-outside-africa/" target="_blank">said Patrick Roberts</a> from MPI-SHH. </p>Complex human societies
<p>The shell beads that the team found indicate that the ancient forest dwellers traded with the populations that stayed along the coast. The beads were rounded and pierced, suggesting that they were strung. Earlier dated beads (around 8,700 years old) were made from red ochre nodules. The ancient jewelry is gauged to be similar in age to other "social signaling" materials found in Eurasia and Southeast Asia, according to the authors, which was around 45,000 years ago. This highlights the importance of establishing social connections for these early people through trade and symbol. </p><p>"Together, these artifacts reveal a rich human culture in the tropics of South Asia which was creating and utilizing complex hunting and social technologies to not only survive, but thrive, in demanding rainforest environments," concluded study co-author Patrick Roberts, Ph.D., a researcher at the University of Queensland.</p>
Keep reading
Show less
Neanderthal bones: Signs of their sex lives
Inbreeding leads to a problematically small gene pool.
27 May, 2020
PIERRE ANDRIEU/AFP via Getty Images
In a cave tucked into the limestone hills of the Asturias region of Spain, there lie the remains of a group of 13 Neanderthals that date to between 50,600 and 47,300 years ago.
<p> The site is infamous among anthropologists who study the Paleolithic period for the evidence of what appears to be the <a href="https://www.nytimes.com/2010/12/21/science/21neanderthal.html" target="_blank">massacre</a> and <a href="https://www.thoughtco.com/el-sidron-evidence-for-neanderthal-cannibalism-172640" target="_blank">possible cannibalization</a> of a family: Their bones seem to have been hacked at by stone tools and hammers, probably by another group of Neanderthals, to remove their flesh and marrow.</p><p>But more importantly, for this story, those bones also reveal something of the sex life of the cave's inhabitants. Anomalies and deformations, along with the DNA buried within their bones, suggest that the members of this group (and their parents) were mating with their close kin.</p><p>Lately, much news from the field of paleoarchaeology and anthropology has centered on Neanderthal bedfellows. You would be forgiven for thinking that paleoanthropologists think about little other than paleo-sex. Within the past several years, genetic evidence has emerged that Neanderthals interbred on more than one occasion with both <a href="https://www.sciencemag.org/news/2016/02/humans-mated-neandertals-much-earlier-and-more-frequently-thought" target="_blank">anatomically modern humans</a> and our newfound ancient relative, <a href="https://www.livescience.com/63400-neanderthals-denisovans-mated-leg-bone.html" target="_blank">the Denisovans</a>. One finger bone fragment from Denisova Cave in Siberia is now famous for belonging to a <a href="https://theconversation.com/ancient-teenager-the-first-known-person-with-parents-of-two-different-species-101965" target="_blank">teenage girl</a> who had a Neanderthal mother and a Denisovan father.</p>
<p>But evidence also shows that while some Neanderthals were apparently breeding well outside of the family group, some were also finding mates much closer to home.</p><p>In the remains from El Sidrón Cave, paleoanthropologist Luis Ríos and colleagues found <a href="https://www.nature.com/articles/s41598-019-38571-1" target="_blank">17 examples</a> of congenital anomalies—structural malformations of various body parts that occur while an individual is developing in the womb.</p><p>One young El Sidrón individual, for example, had an oddly shaped patella, the bone that forms the kneecap: It had three lobes rather than just one. This Neanderthal probably had a limp. An adult male in the same cave had a markedly narrow nasal passage and a "retained deciduous mandibular canine," writes Ríos and his co-authors—this adult Neanderthal never lost one of his lower canine baby teeth. That tooth developed a painful cyst, which left its mark on the bone of his jaw. Microscopic striations on the tooth itself suggest that he coped with the pain by avoiding chewing on that side of his mouth.</p><p>One possible explanation for these skeletal abnormalities is that they resulted from extremely stressful environmental conditions, such as brutally cold weather and scarce food. A pregnant mother experiencing a lot of physical stress and nutritional deprivation might give birth to an infant with some of the same conditions seen at El Sidrón.</p>
<h3>Inbreeding leads to a problematically small gene pool</h3><p>But DNA tests from these bones indicate that inbreeding and a small population size were likely factors contributing to the physical peculiarities in this family. The 13 El Sidrón Neanderthals share much longer segments of their DNA than would be expected if they were the offspring of non-relatives.</p><p>Genetically, the three adult males in the group were closely related enough to be brothers, cousins, or uncles, while the four adult females in the group came from three distinct genetic lines. While all individuals were likely distantly related to one another (think third or fourth cousins), it is likely that the <a href="https://www.nytimes.com/2010/12/21/science/21neanderthal.html" target="_blank">males exchanged females</a> with another local, slightly less closely related group.</p><p>Today inbreeding carries connotations of "kissing cousins" or intimacy between even closer familial relations. But the term simply means mating between relatives, which increases the number of common ancestors in a family tree and the likelihood of inheriting deleterious genes from those common ancestors. Even third or fourth cousins are genetically similar enough for issues to arise.</p>
<p>The younger El Sidrón individuals (ranging in age from 5 to 15 years of age, along with one infant) were likely the offspring of at least some of the adults. At least one of these children, the young male mentioned above, possessed skeletal malformations that were likely passed down from parents who were fairly closely related.</p><p>The tangled familial ties of the El Sidrón Neanderthals are not a unique situation; DNA evidence from other Neanderthals <a href="https://www.sciencedaily.com/releases/2016/06/160606103654.htm" target="_blank">elsewhere in Eurasia</a> also shows elevated instances of shared DNA segments around this time, suggesting that mating between individuals who shared recent ancestors was fairly frequent, and possibly unavoidable, if local populations were small.</p><p>In general, inbreeding leads to a problematically small gene pool. Rare harmful traits that might disappear in larger populations tend to be amplified if close kin interbreed. Yet inbreeding has happened throughout human history, especially in the royal families of different cultures. Just look at the <a href="https://www.livescience.com/3504-inbreeding-downfall-dynasty.html" target="_blank">Habsburg family line</a> in Spain or the <a href="https://www.ancient-origins.net/news-general/study-presents-evidence-extensive-inbreeding-among-ancient-egyptian-royalty-003045" target="_blank">royal families of Ancient Egypt</a> to see the effects of keeping family bloodlines "pure."</p>
<p>Neanderthals were not the only ancient hominins to mate with their close relatives. Anatomically modern humans have also been found with <a href="https://www.sciencemag.org/news/2018/11/frequent-inbreeding-may-have-caused-skeletal-abnormalities-early-humans" target="_blank">skeletal evidence of inbreeding</a>, such as abnormally bowed thigh bones, deformed arm bones, and even a case of a toddler with a swollen brain case <a href="https://www.mayoclinic.org/diseases-conditions/hydrocephalus/symptoms-causes/syc-20373604" target="_blank">consistent with hydrocephalus</a>.</p><p>At the time that these congenital malformations appear, between 100,000 and 50,000 years ago, modern humans were traveling out of Africa. They fanned out across vast geographical regions, and, at times, were quite isolated from one another. Populations might have been separated by hundreds of kilometers at a time, only rarely encountering one another. This might be a simple reason why inbreeding occurred: Pickings were slim.</p><p>During the time that the El Sidrón Neanderthal family occupied their cave, it is likely that they were also fairly isolated. Their mating patterns probably had much more to do with small population size and low population density than any sort of cultural practice. There is no way to know if cultural taboos against mating with close relatives existed back then.</p><p>Interestingly, most of the individuals in the El Sidrón family group lived well past infancy despite physical conditions that, in some cases, would have made it difficult for them to get around and perform their day-to-day tasks. This family cared for one another, sharing physical burdens and helping each other to survive. Their relations, and their care, are recorded in their bones.</p><p><em>This column is part of an ongoing series about the Neanderthal body: a head-to-toe tour. See our <a href="https://www.sapiens.org/column/field-trips/neanderthal-anatomy/" target="_blank">interactive graphic</a>.</em></p><p>This work first appeared on <a href="https://www.sapiens.org/" target="_blank">SAPIENS</a> under a <a href="https://creativecommons.org/licenses/by-nd/4.0/" target="_blank">CC BY-ND 4.0 license</a>. Read the <a href="https://www.sapiens.org/column/field-trips/neanderthal-sex-lives-bones/" target="_blank">original here</a>.<img src="https://www.sapiens.org/track/10451-1590563253735/?dt=Neanderthal+Bones%3A+Signs+of+Their+Sex+Lives&dl=https%3A%2F%2Fwww.sapiens.org%2Fcolumn%2Ffield-trips%2Fneanderthal-sex-lives-bones%2F" alt=""><span></span></p>
Keep reading
Show less
Popular
