Short Wave - Why Chilean Mummies Are Decomposing After 7,000 Years

Episode Date: October 4, 2023

Here on Short Wave, we're getting into the Halloween spirit a little early with a look at the world's oldest mummies. They're found in modern-day northern Chile. The mummies are well-preserved, so over the past 7,000 years, some have been exhumed for scientific study. But recently, something startling happened: Some of the mummies started to decompose. Today on the show, Regina G. Barber talks to archeologist Marcela Sepulveda about the civilization that made these mummies: the Chinchorro people. We dig into the science behind their mummification techniques and how the changing planet is affecting archeologists' ability to study the past. Fascinated by a science mystery? Send us your tales — we're at [e-mail] pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave from NPR. Seven thousand years ago, the hunter-gatherer Chinchuro people thrived in the coastal bays of one of the world's driest deserts. But the rest of the world didn't know about them until the early 1900s when German archaeologist Max Ule visited the Atacama Desert in modern-day northern Chile. Today, archaeologist Marcella Sapovada studies the Chinchoro people, but she says there's not a lot of for researchers to work with. We don't have historic or writing information because they are so ancient. They are the first evidence of the inhabitants

of the coast of the northern Chile and the southern Peru. During Max Ule's first excavation of the Chinchuro Beach in 1917, he uncovered evidence of a civilization. And it was kind of eerie. What the team found for dozens of mummies. Now, Marcella says one port city in this region of northern Chile, Arika, is a necropolis, a graveyard built above these mummies.

And she says the Jinchoro mummies are about 7,000 years old. That's two millennia older than the Egyptian mummies. We don't have any similar mummification techniques present in other tradition or region in the world. Years after Max Ule's first excavation in 1917, the mummies were placed in a museum in Arica, Chile, where they sat, only studied by a few researchers. That is, until the last decade, when museum scientists noticed the mummies had started to decompose. Some of the specimens were even turning to black ooze. Now, more people were paying attention. Scientists like Marcella believe this decomposition has to do with the increased humidity-related

to climate change in this region. So today on the show, we dig into what we know about the Chinchura people, the science behind their mummification techniques, and how the future of our planet is affecting how archaeologists study the past. I'm Regina Barber, and you're listening to Shortwave from NPR. Before we get into why these mummies are decomposing, let's start with how the Chinchuro people actually mummified their dead. So Marcella, you said the German archaeologist, Max Ula,

was really surprised in the 20th century at the techniques they used, right? Like filling the bodies with natural materials. What did he see? They preserve the bone in some case and they preserve also the skin. In some case, they just preserve the bone and construct a body with clay and other materials around the bone. They use sand, clay, feather and the pigment. they use also digital fibers.

They use all that they can obtain from the environment. For a long time, scientists couldn't actually see inside the mummies. But archaeologists like Marcella are now figuring out how to use CT scans to see their bones, how they were constructed. So far,

Marcella says it seems like the Chinchuro people had an impressive understanding of anatomy. They know also how to take out their organs from the body. They put particular cut in the body to

extract all the organs and the muscle to take out them. It's surprising because we don't have archaeological information now about this type of

process and knowledge in other region of the world. Sometimes they even altered the bone structure of the deceased. And so you have a child, for example, from three or four years that appear to be bigger, like a child of six or seven years, they modify the bone structure. They also move the different bones of the body. They play with the body, with respect, of course. Marcella thinks that many of these changes to the body had to do with aesthetics.

But to some extent, these treatments may have also helped protect the mummies from the elements over thousands of years, keeping them safe so they wouldn't decompose. In the coast, we have lots of humidity, wind, and other natural factor that contribute to degradate the body and the skin. So it is very interesting to see that they could present. the skin without the degradation. It's like if they know how to interact the body with the environment, and they use the sand and other elements that contribute to preserve the body.

Marcella says the oldest of the Chinchuro mummies are actually fetuses and children, and that the mystery of why they mummified their youngest members may have to do with the local water source that the Chinchuro people live by. The river of the northern Chile are natural contaminate. They present lots of pollution like arsenic and other minerals because the water came from the Andean mountains and the Andean Cordillera de los Andes are naturally contaminate. And that contamination shows up in the mummified. bodies. The body present high level or arsenic or mercury or other chemical elements that indicate that they were exposed to high level of contamination of pollution. And that's why

maybe we can observe high child mortality. And that maybe explain why they begin. to mummify child. And the Chinchuro people didn't just mummify the youngest members of their society. They mummified everyone. If you see other mummification techniques present in the world, in general, the mummification concern the elite people. In the Chinchuro case, they mummificate all the individuals, babies, child, but also adults. And members of their community with physical disabilities.

You can observe that several bodies have a malformation or problems in bone structure, but they lived. So you can observe that they care about everybody during the life. Oh. And they also preserve and take care about the deaths. And these preservation methods worked for. a really long time, until now. In the last decade, museum scientists in Chile have seen the excavated mummy start to decompose rapidly. Marcella and other researchers think it might have something to do with climate change. In effect, you have the climatic change observed in all the

world, and you can observe an increase of natural humidity. That was the theory, that he Humidity was causing this decomposition. Marcella and a team from around the world wanted to test their hypothesis in the lab to see how mummy skin held up against humidity. And to do this, they had to think about what was on the skin. They figured out the culprit was microbes. But were the microbes coming from the environment or the skin? To figure this out, they took skin samples from the mummies, pulled out microbes they found, and attempted to grow these microbes in a lab.

Then, we're growing the microbiome and put it on the skin. When we increase the humidity, we observe that the degradation increase a lot and very fast. So we could identify at this moment that in effect the microbioma was sleeping, and wake up with some modification of the humidity. The microbes flourished in the high humidity, ultimately causing the skin samples to break down. Mystery solved. Even without the knowledge of the microbiome we have today,

it's clear that the Chinchura people's understanding of anatomy was impressive. They had lots of knowledge about the body, about not only how to prepare the body, and how to make the mummies, but also how to preserve the skin and stop the process. Wow. And it's amazing. But now, archaeologists are tasked with finding new ways

to preserve both the excavated and the buried mummies that may be at risk of being uncovered either by development or natural processes. In museums, Marcella and her colleague can do this by adjusting humidity levels, but for hundreds of mummies still in their arrids, often shallow burial sites, that's not an option. They're still vulnerable to the effects of climate change. And that's part of why Marcella hopes more people will learn about the mummies

and try to protect them in the years to come. So Marcella, these are the oldest mummies in the world that we know of, but they're not as well known as maybe the Egyptian mummies. Why do you think that is? In general, the team are Chilean researcher, and we don't have maybe the impact of other research in the world. Here in Chile, if you ask to people who live in Arrica, where the archaeological sites are,

lots of people don't know that Chilchuromami are there. So it is also not a responsibility of the researcher, it is also a responsibility of the country to share the knowledge about the Chinchoro and the importance to preserve this type of archaeological sites and mummies. Marcella, thank you so much for talking with me today. Thank you. I learned so much.

It was very nice to share about the Chinchor mummy and the amazing world of Chinchero culture. In 2021, the United Nations Educational Scientific and cultural organization, UNESCO, made the Chinchuro Mummies and Settlement a World Heritage Site. If you've been enjoying this episode, give us a follow so you can get alerted each time we publish a new episode. This episode was produced by Rachel Carlson and edited by Burley McCoy. Anil Oza checked the facts and the audio engineer was Maggie Luthor. Beth Donovan is our senior director and Anya Grunman is our senior vice president of programming.

I'm Regina Barber. Thank you for listening to Shortwave from NPR.