Welcome back, everybody!  This is Rick Pettigrew to share with you a whole new weekly batch of top news stories that appeared on Archaeologica!  Send us feedback on The Archaeology Channel Facebook page or post a message on our social networking site, ArchaeoSeek!

A medieval furnace in Cambodia reveals a previously unknown shift in the Earth’s magnetic field.  

A new study of a large sample of people suggests that a reduced water requirement was an adaptive advantage for our distant ancestors competing with other primates.  Examination of hunter-gatherer groups shows that many factors affected how women participated in hunting along with men.   And ancient use of a cave in Spain is reflected in some fragile footprints made clearer by new technology..

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Welcome to the Audio News from Archaeologica! I’m Laura Pettigrew, and these are the headlines in archaeological and historical news from Archaeologica for the week of March 7th through the 13th, 2021.       

Our first story takes us to Cambodia, where an ancient furnace at an iron-smelting site has given us insight into Earth’s changing magnetic field.

As reported at the website, Inside Science.org, a team of archaeologists and earth scientists drew new data from the thousand-year-old furnace site’s baked earth and slag to develop the first archaeomagnetism records from southeastern Asia.

Earth’s magnetic field is generated by metal flowing in the outer layer of the planet’s core, creating electrical currents.  The magnetic field surrounds the planet and protects it from harmful materials heading toward us from the sun and other cosmic entities.  We know that the field changes frequently in both direction and strength, but the record prior to 400 years ago is very spotty.  Some scientists have hypothesized that changes in the magnetic field’s direction or strength over time have caused major extinction events, and even changes in human behavior.  

Reconstructing the planet’s past magnetic fields and shifts helps determine how frequently such shifts have occurred on both global and localized scales.  Data from southeast Asia have been scarce, though, so the new research, led by geophysicists from Scripps Institute at the University of California San Diego and archaeologists from the University of Illinois, has been a welcome way to fill in some of the gaps. 

The team drew their data from three furnaces at a Khmer Empire iron-smelting site used between 1100 and 1300 AD.  By examining iron waste at the site, including furnace fragments, slag waste left over from iron smelting, and pipes used to bring air into the mix, researchers discovered that the field made a sharp directional change, westward and then eastward, between AD 1200 and 1300.  The field also seems to have significantly weakened during these centuries, suggesting anomalies at the Earth’s core fueled these changes. 

If it happened today, a weaker magnetic field would provide less protection against solar storms or cosmic rays, risking harm to power grids and satellite communication systems. 

The new findings from the past will help scientists understand how the planet’s magnetic field may change in the future, and how we could protect ourselves when it does.  The new research is published in Proceedings of the National Academy of Sciences.

Our next story takes us to the distant past, and evolutionary biology research showing that one key step in early human evolution - and out onto the savannas - was developing a lower water need compared to our primate kin. 

As reported by the science website, Phys.org, the study compared water turnover from 309 individuals spanning different lifestyles and occupations, from high-intensity farming and hunting work to desk jobs, with that of primates living in zoos and sanctuaries. 

The results showed that on average, a human processes about twelve cups of water each day, which is only half that of the average zoo gorilla or chimpanzee. 

The findings are surprising because humans are unique among primates in our ability to sweat much more than our primate cousins.  We have ten times more sweat glands than chimps, so in an hour workout, for example, we sweat out more than half a gallon of liquid.

The crucial change appears to be an adaptive shift that allowed us to use water more efficiently than other apes.  Researchers hypothesize that our thirst response shifted over time, so that we crave and consume slightly less water.  Human breast milk seems to back this up, for example, showing a 25 percent lower water-to-calories ratio than the milk of other primates. 

At the same time, fossil evidence also suggests that the change in the design of our noses helped us save water.  By 1.6 million years ago, human primates developed a nose that sticks out from the face.  Inside it, the nasal passages help conserve water by cooling and condensing exhaled air, so that liquid can be reabsorbed in the nose. 

Increased water efficiency would have allowed our hunter-gatherer ancestors to travel farther from streams and watering holes in search of food.  According to lead author Herman Pontzer, associate professor of evolutionary anthropology at Duke University, this would have been a big advantage as early humans started making a living in dry, savannah landscapes.

We could still only survive a few days without water, but as Pontzer put it, while the shift didn’t break that ecological leash, we got a longer one, letting early humans forage more widely than other primates. 

The next step, researchers say, is determining just how this physiological change happened.  More mysteries remain to be solved, but what’s clear is that we’re saving water.  Now we must figure out exactly when and why that’s the case.  

The new research appears in the latest issue of Current Biology.

Our next story began in Peru with the burial of a female hunter who contradicted old stereotypes about gender roles in hunting and gathering societies.  To gain more insight, we go to Malaysia, where data from a present-day hunting-gathering group suggests that women’s flexibility in gathering versus hunting roles involves considerations of childcare, risk and lifelong investments in expert knowledge.

As reported on the science website, Phys.org, excavations at the Wilamaya Patjxa site in the Andean highlands uncovered a 9,000-year-old burial site of a young adult female with big-game hunting paraphernalia like stone projectile points and animal processing tools.  This once again showed the problem with stereotypes that man is the hunter and woman the gatherer, and that hunting was key to development of chiefdoms and states, while gathering was unimportant and thus gave women gatherers low status.  

It’s long been known that none of these stereotypes are true.  Ever since the famous “Man the Hunter” symposium organized by Richard Lee and Irven DeVore in Chicago in 1966, research makes clear that women have always hunted as well as men, though in much lower numbers, and that gathering was often the key to survival and success.  The question, then, is what the factors are.  When and why do women decide to participate in hunting? 

Data from the Batek people of the Malaysian rainforests helps answer these questions.  

The Batek hunter-gatherers are noted for their extreme egalitarianism and peacefulness.  Their skills and knowledge in both hunting and gathering have long been studied by Dr. Vivek Venkataraman, from the department of Archaeology and Anthropology at the University of Calgary, in Canada.  Venkataraman’s research shows that gathering is physically intensive and challenging.  At the same time, the tribe has no prohibition on women hunting, and girls take an interest in blowpipe hunting that carries into their adulthoods.  Women sometimes hunt bamboo rats near the village, but hunting monkeys takes one farther into the forest and is more commonly done by men.

The factors in women’s decisions to hunt include the burdens of childcare, the location of available hunting, the levels of speed and strength that might be required, and the specialist skills and knowledge involved in both hunting and gathering activities.  In ancient Peru, the big-game hunting that the young women took part in relied on spear-throwing, a relatively easy technology to learn.  Among the Batek, however, both genders learn blowpipe hunting technology, but it’s mainly men who pursue it as adults.  Gathering skills, however, rely on knowledge of a complex diversity of plant foods that takes a lifetime both to learn and to constantly monitor.  Knowing when the camp will need to be moved in response to plant availability is crucial to the group’s survival.  

Hunting and gathering turn out to be just the far ends of the scale.  In between, women have often been involved in both gathering and hunting, by supporting male hunters through ritual, through crafting their tools and materials, and through working on the drive lines and processing the meat and hides.  A steadily increasing data-set on past and present hunter-gatherer decision-making suggests that these factors of skill, risk and knowledge, along with the needs of child care, play into women’s decisions on which role to take.  

Our final story of the week brings us to Spain, where researchers have used new technologies to examine 1200 footprints from over four thousand years ago. 

Researchers at the Ojo Guareña [O-ho gwar-EHN-ya] Karst Complex in Burgos, Spain have used high-tech tools to study fragile footprints left by ancient bare feet traveling the soft floor sediment of the Sala y Galerías de las Huellas [HWAY-yahs] site.  Dating at this site has shown that it was heavily trafficked during the Neolithic, Mesolithic and Upper Paleolithic eras, affirming that humans were traveling back and forth to this cave complex throughout prehistory. 

As reported on the science website, Phys.org, the latest study of the footprints reveals that a small group of about ten humans traveled into the cave between 4600 and 4200 years ago.  The footprints were originally discovered back in 1969, but were too fragile to examine using existing technologies.  New research with 3-D scans and digital photography, in combination with GIS techniques, has revealed their details.  The research also includes radiocarbon dating of residue left from the group’s torches. 

Access to this deep cave system is remarkably complex, and researchers are still determining how it was used, and for what purposes, by prehistoric people.  

The new research is one chapter in a new monograph published by Springer Nature, dedicated to the research and analysis of prehistoric human footprints preserved around the world. 

It seems there is still much more to discover about prehistoric people’s relationship with the subterranean world. 

That wraps up the news for this week!

For more stories and daily news updates, visit Archaeologica on the World Wide Web at www.archaeologica.org where all the news is history!

I’m Laura Pettigrew and I’ll see you next week!