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Tag: anthropology

250,000-Year-Old Child Adds to the Mystery of Our Human Origins

Based on the small size of Leti’s skull and on the combination of baby teeth and unerupted adult teeth, researchers estimate that the Homo naledi child would have been 4-6 years old.

Look at the palm of your hand and spread your fingers wide. Now imagine squeezing your body through a gap narrower than the distance between the tip of your thumb and the tip your pinkie finger. Let’s make this a bit worse: the gap is in complete darkness, its walls are rough stone, and all you have is a tiny headlamp. Ok, now that you are there, all you have to do is carefully find and recover dime-sized fragments of an invaluable treasure.

That’s how researchers recovered the first Homo naledi child’s skull ever to be found.

The finding was revealed this week in two papers published in the journal PaleoAnthropology by an international team of 21 researchers.

Homo naledi are possibly our most mysterious long-lost cousins. They are an ancient human relative that lived in what is now South Africa, approximately 350 to 250 thousand years ago. They were first discovered in the Rising Star Cave system in 2013, in a research expedition led by Lee Berger, Professor and chair of Palaeo-Anthropology and Director of the Centre for Exploration of the Deep Human Journey at the University of Witwatersand.

The research team, which includes Steven Churchill, professor of evolutionary anthropology at Duke, named the child Leti (pronounced Let-e), after the Setswana word “letimela” meaning “the lost one”.

Leti was found in one of the previously unexplored narrow fissures that radiate from Rising Star’s known chambers. His resting site was a 15 cm wide and 80 cm long gap where only the smallest (and bravest) of explorers could fit.

Explorer Becca Peixoto wedges herself between cave rock walls to get to Leti’s skull.

Marina Elliot, lead author of the first paper and one of the explorers to first discover Homo naledi, said in a press conference that excavating Leti’s remains required explorers to wedge themselves practically upside down between two rock walls.

Finding yet another fossil in a prolific site may not seem groundbreaking, but finding a child’s skull is a major achievement. First of all, children’s bones are thin and fragile, and rarely withstand the test of time.

Second, finding a child’s skull gives researchers a precious glimpse into the development of Homo naledi.

“A child’s skull allows us to study how Homo naledi grew and developed, and how their growth rate and schedule compares to other hominid species, and to our own,” Churchill said.

In addition to skull fragments, researchers also recovered two worn baby teeth and four unworn adult teeth that were yet to erupt. These findings show that Leti would have been between four and six years old at the time of her or his death.

Based on similarities between the soil of the fissure where Leti was found and the better-known areas of the cave, Tebogo Makhubela, senior lecturer of Geology at the University of Johannesburg and author of the papers, estimated that Leti has been hidden in Rising Star for over 250,000years.

The discovery of Leti’s skull also deepens the mystery of how Homo naledi’s remains ended up in such a deep, dark, and treacherous cave.

Berger’s team had previously hypothesized that the first 15 Homo naledi individuals found in Rising Star had been disposed there by their own species, as a burial. This hypothesis created an uproar: could a small-brained hominin from over 300,000years ago bury their dead, just like we do?

Leti’s skull was found on a small shelf at the back of the cave’s fissure. No other bones were found, suggesting that Leti’s head may have been deliberately placed there. Leti, as well as all other Homo naledi fossils ever found, showed no evidence of being dragged by predators, carried by water, or tumbled around in any other way.

“Those were social individuals. Seeing one of their own being picked apart by animals could have been very distressing,” Churchill said. “Purposeful disposal of their bodies still seems like the most likely explanation.”

Berger is undeterred by nay-sayers. “This is science,” Berger said at a press conference. “We will continue testing and challenging our hypotheses with every piece of data that we get.”

The researchers hope that other teams around the world will study Leti and other Homo naledi fossils. To that end, Leti’s skull was CT-scanned, and its scans can be downloaded from Morphosource, an open access repository of museum specimens’ 3D scans hosted at Duke University.

Leti will probably not be the last treasure to come out of Rising Star’s spider web of narrow passages.

“I can’t wait to go back to South Africa and see what else is waiting for us in that cave,” said Juliet Brophy, Professor of Geography and Anthropology at Louisiana State University and lead author of the paper describing Leti’s skull.

“This finding makes us remember that exploration is always worth doing,” said Elliot, who is a researcher at Simon Fraser University and Witwatersand University. “There is a lot still out there to be found”.

The Rising Star cave system is known for being extremely dangerous to explore.

Elliot et al. was funded by the National Geographic Society, the Lyda Hill Foundation, the South African National Research Foundation, and the Gauteng Provincial Government, for funding the discovery, recovery and ongoing analyses of the material. Additional support was provided by ARC (DP140104282).

Brophy et al. was funded by the National Geographic Society, the Lyda Hill Foundation, the South African National Research Foundation, the South African Centre for Excellence in Palaeosciences, The University of the Witwatersrand, the Vilas Trust, the Fulbright Scholar Program, Louisiana State University, North Carolina State University, the Texas A&M University College of Liberal Arts Seed Grant program and the Texas A&M College of Liberal Arts Cornerstone Faculty Fellowship.

Citations:

“Expanded Explorations of the Dinaledi Subsystem, Rising Star Cave System, South Africa.” Marina C. Elliot,Tebogo V. Makhubela, Juliet K. Brophy, Steven E. Churchill, Becca Peixoto, Elen M. Feuerriegel, Hannah Morris, Rick Hunter, Steven Tucker, Dirk Van Rooyen, Maropeng Ramalepa, Mathabela Tsikoane,Ashley Kruger, Carl Spander, Jan Kramers, Eric Roberts, Paul H.G.M. Dirks,John Hawks,Lee R. Berger. PaleoAnthropology, November 2021. DOI: https://doi.org/10.48738/2021.iss1.68.

“Immature Hominin Craniodental Remains From a New Localityin the Rising Star Cave System, South Africa.” Juliet K. Brophy, Marina C. Elliot, Darryl J. De Ruiter, Debra R. Bolter, Steven E. Churchill, Christopher S. Walker, John Hawks, Lee Berger. PaleoAnthropology, November 2021, DOI: https://doi.org/10.48738/2021.iss1.64.

By Marie-Claire Chelini
By Marie-Claire Chelini

Paleo Fact and Fiction: the Key to Being Healthy

Humans have conquered smallpox and drastically reduced child mortality rates, yet we now face problems never seen before. Conditions like heart disease, obesity, cancer, and diabetes pose serious threats to our health. How can we overcome them? The answer may lie in our past.

Herman Pontzer, an associate professor of evolutionary anthropology at Duke, thinks we have something to learn by looking at hunter gatherers.

For most of human evolution, we had to work for our food. Recent developments like supermarkets and cities are strange and have flipped the script on daily life. Pontzer believes if we could live more like our ancestors, maybe we wouldn’t get sick.

Pontzer started off by studying a hunter gatherer group in Tanzania known as the Hadza. The Hadza cling tight to cultural traditions and live off the land in the African savannah. There are no domesticated animals, no guns, and no vehicles. Women spend their days digging for fibrous tubers and gathering berries and baobab fruits. When men aren’t hunting game, they collect honey. Honey plays a major role in the Hadza diet — around 15-20% of their caloric intake.

The Hadza live a very active lifestyle. They walk between 13,000 and 20,000 steps a day, compared to the generic Fitbit goal of 10,000 steps (which most of us don’t even meet, if we’re being honest).

Curious to see if the Hadza’s vigorous activity levels had something to do with their superior health, Pontzer used the doubly labeled water technique to measure total energy expenditure. Shockingly, he found that Hadza and Americans burn the same amount of calories on average.

All our lives we’ve been told exercise converts to burned calories. But evidence from the Hadza tells us this is not the case. What really happens is natural systems in our body adjust to suppress other activity, keeping total expenditure constant. This means that exercise alone is an ineffective tool for weight loss. But don’t quit the gym quite yet — while the Hadza spend most of their total energy being active, an inactive body will spend it on unhealthy things such as inflammation and stress reactivity. This constrained energy mechanism makes exercise essential for overall health. But in the words of Pontzer, “in order to end obesity, we need to fix our diet.”

Image result for paleo diet

The idea that the “paleo diet” is necessarily low-carb is a myth, Pontzer says. Hadza rely heavily on starches and fructose for sustenance. Furthermore, what you eat as a hunter gatherer is entirely dependent on geographical location. Hunter gatherer diets do things in common, though: they eat no processed foods, and energy dense foods are hard to come by. 

Never before have we had so much food high in energy available at such a low effort. In supermarkets, the cheapest food is the most rich in energy. In the wild, it’s the complete opposite. Pontzer says, “traditional diets are diverse, modern diets are perverse.”

Image result for supermarket cereal aisle

He calculated that an American can get twenty times as much food energy in an hour’s work as a Hadza could with the same effort. Plus, the Hadza don’t have irresistible Doritos they can’t stop eating. When the Hadza are full, they’re full.

The Hadza are naturally protected from the same “diseases of civilization” that we are likely to die from. A beautiful combination of diet and how they expend energy provides a shield that modernization seems to have taken from us. Energy has become too available. But staying healthy is still in our control. It’s about finding the right balance of exercise and eating right.  

There is still a lot to be learned from hunter gatherer societies. For now, let the Hadza inspire you to get outside, get active, and cut out processed foods!

Chronicling Migrant Deaths Along the US-Mexico Border

Science, especially social science, is rarely apolitical. Nonetheless, researchers are often hesitant to engage with the political implications of their work. Striving to protect their objective, scientific stance, they leave the discussing and at times the fighting to the politicians and legislators.

University of Michigan anthropologist Jason de León is not one of those researchers. Politics is not merely implicated in his work, but rather drives it. De León studies undocumented migration between Mexico and the United States.

University of Michigan anthropologist Jason De León directs the Undocumented Migration Project.

University of Michigan anthropologist Jason De León directs the Undocumented Migration Project.

As director of the Undocumented Migration Project, De León studies what happens to the bodies of migrants crossing the desert to reach the U.S. using “any genre I can steal from,” he told an audience at Duke University on April 5. Using tools from archeology, forensics, photography, and ethnography, de León and his team have been providing novel insights into one of the most urgent political challenges currently facing the nation.

De León acknowledged the political reality of his work immediately by opening his talk with a quote from President Trump about building a “great wall.” However, he was quick to clarify that the problem of missing migrants is not partisan. Rather, it has a long history that he argues started with the 1993 immigration enforcement policy, “Prevention through Deterrence.” This policy’s aim was to redirect illegal immigration to the desert rather than to stop it. Politicians hoped that in the desert, where security is weak and the terrain treacherous, the natural terrain would serve as a border wall. Inherent in this policy is the assumption that migrant life is expandable.

In the wake of this policy, the human smuggling industry in northern Mexico experienced a swift influx and the number of known migrant deaths began to rise. Since the 1990s, over 600 migrant bodies have been recovered from the Sonoran Desert of Arizona where de León conducts his research. Until his team conducted the first forensic experiments on the site, people could only speculate as to what was happening to the bodies of missing loved ones hoping to make it across the border. Now, de León can offer some helpful if heartbreaking data.


De León examines the human consequences of U.S. immigration policy in his book, “The Land of Open Graves”

De León’s archeological method, “desert taphonomy,” examines both the natural and cultural processes that determine what happens to a dead body. Anthropologists studying the body’s decomposition were initially interested only in natural factors like the climate and scavenging animals. Recently, they have realized that the decomposition process is as social as it is natural, and that the beliefs and attitudes of the agents involved affect what happens to human remains. According to this definition, a federal policy that leaves dead bodies to decompose in the Arizona desert is taphonomy, and so is the constellation of social, economic, and political factors that drive people to risk their lives crossing a treacherous, scorching desert on foot.

Guided by this new approach, de León studies social indicators to trace the roots of missing bodies, such as “migrant stations” made up of personal belongings left behind by migrant groups, which he says can at times be too big to analyze. De León and his team document these remnants with the same respect they pay to any traditional archeological trail. Items that many would dismiss as trash, such as gendered items including clothes and hygiene products, can reveal much needed information about the makeup of the migrant groups crossing the desert.

De León argues that human decomposition is a form of political violence, caused by federal policies like Prevention through Deterrence. His passion for his research is clearly not driven by mere intellectual curiosity; he is driven by the immense human tragedy of migrant deaths. He regularly conducts searches for missing migrants that families reach out to him about as a desperate last measure. Even though the missing individuals are often unlikely to be found alive, de León hopes to assuage the trauma of “ambiguous loss,” wherein the lack of verification of death freezes the grief process and makes closure impossible for loved ones.

The multifaceted nature of de León’s work has allowed him to inspire change across diverse realms. He has been impactful not only in academia but also in the policy and public worlds. His book, “The Land of Open Graves,” is accessible and poetic. He has organized multiple art exhibitions that translate his research to educate and empower the public. Through the success of these installations, he has come to realize that exhibition work is “just as valuable as a journal article.”

Backpacks left behind by undocumented immigrants in the exhibition,
“State of Exception.”

Hearing about the lives that de León has touched suggests that perhaps, all researchers should be unafraid to step outside of their labs to not only acknowledge but embrace the complex and critical political implications of their work.

Guest Post by Deniz Ariturk

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