When Scientists Scanned A Jungle With Light Waves, They Discovered A Monumental Mayan Secret

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High above the canopy of a Belize wetland, researchers hover as they gather data about the earth below. They can’t see through the leaves to the ground – but the laser beams that they fire from their aircraft certainly can. And as the light bounces back up, it reveals a secret about the ancient Mayan people who once roamed here.

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The Birds of Paradise wetlands were just one place that the Mayans had once inhabited. The marshy covered a two-square-mile stretch of land, and it has been extensively studied by experts for decades. But modern technology allowed them to see this swathe of land as they never had before.

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And for those specializing in Mayan culture and civilization, such an advancement changed so much about what they knew about these people. What was once a massive population disappeared with the last city to fall in 1697: Nojpetén. Considering the wetlands that they once inhabited, it’s no surprise that much of their remnants faded away with them – or so we thought. Now experts have a new way of uncovering their tracks, and they’ve revealed some startling truths about Mayans.

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Hunter gatherers once roamed Central America, but the Pre-classic period – which stretched from 1800 B.C. to A.D. 250 – saw these wanderers put down roots. Among them were the Mayans, who began to build cities across the region. They inhabited all of modern-day Belize and Guatemala, as well as parts of Mexico, Honduras and El Salvador.

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Between A.D. 250 and 900, the Mayans hit the peak of their influence, and their rise to the top was more or less unmatched. In his 2011 book The Maya, Yale professor Michael Coe explained how they “reached intellectual and artistic heights which no other in the New World, and few in Europe, could match at the time.”

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Among the Mayans’ triumphs were their advances in both astronomy and math. For one thing, they created a calendar system, which counted 365 days per year. Obviously, that count was accurate. Plus, they used zero in their calculations, and the Mayans were the second population to do so. They discovered the figure separately from the Mesopotamians, who used zero in 4 B.C.: 700 years before the Mayans discovered the digit on their own.

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The Mayans’ advancements also included their art and architecture. Some of their creations still stand, and, interestingly, each Mayan city seems to have had its own signature style of construction. For instance, Tikal mastered the art of pyramid-building, and their leaders would order a new one to be built every 20 years.

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On top of that, the Mayans devised a system of hieroglyphic writing, which historians began to decipher in the mid-1900s. As such, they could understand the inscriptions left behind in Mayan art and sculpture. They also created books with tree bark, rubber and chocolate. So far, experts have their hands on four such texts.

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Finally, Mayans flourished in a land unlike any other ancient civilization. Most of the time, people gathered on arid lands where they diverted water flow to their cities and villages. The Mayans had no need for such infrastructure because they settled in lowlands. As Coe put it in The Maya, they developed “really effective farming” as evidenced by their “densely inhabited villages.”

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In spite of all of their triumphs, though, the Mayans dispersed between the eighth and ninth centuries from the lowlands, and, as we noted, their last city fell in 1697. They didn’t record their reasons for disappearing in their ancient tree-bark texts, but scholars have their own suspicions about what happened. Some say that they ran out of resources to support their massive cities, while others believe that conflict with other civilizations led to their breakdown.

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Some descendants of the Mayans reside in their ancestors’ former territory, with most calling Guatemala their home. But experts have spent centuries trying to study their ancient family members, with few remnants accessible to them. As previously mentioned, they only have four Mayan texts, plus the art and sculptures that give a glimpse into the civilization’s way of life.

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Finding more about the Mayans isn’t as simple as excavating their old stomping grounds, either. Much of their former territory hides beneath thick jungle foliage. As such, archaeologists have had to trek to former cities and villages and spent years mapping them. But now, technology is revolutionizing the way that they can uncover the secrets of these lands.

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Namely, scientists and archaeologists have lidar – light detection and ranging – on their side. This technology emits pulsed laser light, which it then uses to calculate the distance to the Earth’s surface. Meanwhile, the system gathers further information to paint a picture of what the terrain looks like below.

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On that note, most lidar systems are installed into airplanes or helicopters, so experts can gather data over sweeping stretches of the earth. They can use the technology over both water and terrain. Green light scopes out seabeds, while infrared laser beams can create a topographical map.

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Researchers have already used this technology to uncover new information about the Mayans. For instance, in 2018 researchers jetted over a one-time Mayan stronghold in the lowlands of Guatemala. They flew over and over the same land to map what lay beneath the thick canopy of foliage.

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Lidar gave researchers the ability to map the ground, even capturing the outlines of features a mere yard in size. Laser beams slipped through the gaps between jungle trees and traveled down to the ground, sending data back to scientists. Knowing how long it took for the light to hit the ground and bounce back showed them the ground’s elevation, even if they couldn’t see it.

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This particular project had scientists examining more than 770 square miles of former Mayan lands. According to Eos, the team called it “the largest single lidar survey of Mesoamerican technology.” And their findings uncovered a lot of new information about the everyday lives of this ancient civilization.

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Broadly, the researchers found a stunning number of Mayan structures in this stretch of the Guatemalan jungle – more than 61,000, to be exact. And they didn’t just find the shells of ancient Mayan buildings. Lidar also revealed roads that may have connected outlying areas to city centers, which hinted that these metropolises were more important than experts once believed.

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The roads and many other remnants of infrastructure – such as homes and gardens – told researchers that this settlement had been much larger than they thought, as well. They recalculated and realized that hundreds of people would have fit into every square mile of this settlement, just north of Tikal.

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Study co-author Thomas Garrison described, “In certain parts of these areas… every little rise and hillock in the landscape has a family living on it, extending for miles outside of places like Tikal. When you step out of your house in the morning, you look out, you’re seeing all of your neighbors right there, everyone’s right on top of each other.”

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Consequently, the lidar-based findings pushed estimates of the Mayan population’s size to new limits. Some figured that, during its peak, the civilization counted 10 million people among its ranks. Of course, it’s impossible to calculate the exact figure, but experts can agree that the Mayans dominated the lands that they had inspected with lidar.

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Other areas of Mayan territory have yielded less information for researchers. The north-of-Tikal settlement had plenty of buildings and signs of human innovation, such as roadways and agriculture. Meanwhile, researchers found areas with more fields than buildings. They also uncovered purely urban zones too.

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But that variation pointed to the complexity of Mayan society, according to study co-author Marcello Canuto. He said, “Like any map that you see of any modern nation or any populated ancient context or modern context, you’re going to have places where people congregate, and people live more closely together and are more dense, and places where they don’t.”

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Considering the wide swathe of land once held by the Mayans, the researchers have plenty of work to do in examining it all. Francisco Estrada-Belli explained it best to National Geographic in 2018, saying that lidar was “revolutionizing archaeology the way the Hubble Space Telescope revolutionized astronomy.” But it provided so much information that they’d “need 100 years to go through all [the data] and really understand what we’re seeing.”

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And that continues to be true – lidar has continued to uncover more secrets of the Mayan civilization. A laser-centric search of Belize’s Birds of Paradise wetlands revealed yet another surprising facet of life as the jungle-based population knew it. Namely, researchers revealed in 2019 that they found an extensive series of fields and canals beneath the canopy.

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These one-time fields played host to the crops the Mayans used to feed their massive population: maize, avocado and arrowroot among them. The study also uncovered when, precisely, the Mayans farmed these grounds. Their Belize-based agricultural pursuits took place between 1,800 and 900 years ago.

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Experts knew that the Mayans farmed, and they knew that the civilization had used this region of Belize to grow crops. However, lidar revealed four distinct agricultural areas, one of which was actually much larger than previously thought. And researchers didn’t know about one of them at all until the lidar results bounced back to them.

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And although lidar produces a surprisingly accurate picture of the ground below, researchers backed up their digitized findings with ground research. The team corroborated their agricultural assertions with evidence that they found hidden in the terrain. For instance, they found ancient ash, which indicated that the Mayans had burnt their fields before replanting them.

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Researchers also excavated the ancient canals that they had scoped from above. They performed radiocarbon dating of the soil, and that portion of the project revealed another interesting truth about the Mayans. Even without all of the chemicals and mass production methods of today, their ancient farming methods adversely affected the environment.

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According to Eos, lead author Tim Beach said that the Belize lidar project revealed “early and extensive human impacts on the global tropics.” Indeed, the Mayans had transformed wetlands into a fruitful farmland. Doing so may have created both methane and carbon dioxide emissions, unbeknown to the people tilling the land.

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As such, the Mayans may have been one of the world’s first human sources of greenhouse gas emissions. At the very least, the Mayans’ rota of crops affected the soil in their fields. Specifically, higher isotope levels indicate maize growth in the area, as well as other crops that humans would have grown at the time.

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Considering the massive scale of Mayan farming – which researchers finally grasped thanks to lidar – the ancient people may have produced carbon dioxide and methane in the process. And that paints a new picture of climate change, Beach explained. In a University of Texas at Austin press release, Beach said, “We now are beginning to understand the full human imprint of the Anthropocene in tropical forests.”

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Beach continued, “These large and complex wetland networks may have changed climate long before industrialization, and these may be the answer to the long-standing question of how a great rainforest civilization fed itself.” The lidar also revealed that they may have had trouble doing the latter, facing environmental challenges while they created atmospheric issues themselves.

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Specifically, the Mayans had to contend with rising sea levels, which crept up over a 2,000-year period. After that, they had droughts to worry about during a stretch from 1,200 to 900 years ago. That’s why these ancient civilizations popped up in wetlands: they could engineer canals to measure water quantity and quality too.

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Their efforts made Mayan settlements much less primitive than one might think. Instead, study co-author Sherly Luzzadder-Beach explained, “These perennial wetlands were very attractive during the severe Maya droughts, but the Maya also had to be careful with water quality to maintain productivity and human health.”

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What the Mayans may not have known, though, was that their activities were hurting the planet too. As they expanded their wetland fields to feed their large population, they created carbon dioxide when they burned plants. And they boosted methane levels to the highest that they would reach until the modern era rolled around.

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The Mayans weren’t the only ones producing methane, though. Ancient civilizations in China and South America did so as well. And, as Beach put it, “Even these small changes may have warmed the planet, which provides a sobering perspective for the order of magnitude greater changes over the last century that are accelerating into the future.”

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Perhaps even more surprising is the fact that researchers have only just scratched the surface when it comes to the Mayans’ footprint. They may have used even more of the Central American wetlands than researchers have found yet. So lidar could be deployed in the future to explore this possibility too.

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So far, though, research has only shown that the Mayans had an impact larger than previously thought – and, even before these discoveries, people knew how innovative and important the civilization had been. New discoveries point to Mayans as having a global role during their time, not just a Central American one.

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Beach concluded, “Understanding agricultural subsistence is vital for understanding past complex societies and how they affected the world we live in today.” So research into the Mayans’ lands will have to continue to paint that full picture – and clarify further the connections between the people of the past and us in the present.

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