Beneath the magical rainforest of Brazil lies a mystery that has long been overlooked. In the 30s, a group of archaeologists ventured deep into the rainforest, originally looking for the remains of the Mayan civilization, but accidentally discovered a series of puzzling tunnels. The intricacies of these tunnels, which vary in length and number in the tens of thousands, raise doubts about human causes.
After careful study by scientists, they have carefully determined the structure and age of these tunnels, and the results have surprised the world – these tunnels are 13,000 years old! Such a long time seems to have gone beyond the scope of human civilization. The tunnel is covered with animal paw prints, which apparently have nothing to do with humans. So, how exactly are these tunnels formed? What are the mysteries they hide?
Discovery and suspicion of tunnels
It was the mid-1930s when a group of aspiring archaeologists arrived in faraway South America. Their goal is to follow the traces of the Mayan civilization that disappeared hundreds of years ago in the mysterious country of Brazil, which is covered in tropical rainforests.
After an arduous expedition to finally reach their destination, the archaeologists eagerly began to explore the area. They followed the clues they already had and groped their way through the dense forest, hoping to find traces of where their Mayan ancestors once lived.
However, the deeper it goes, the more disappointing it becomes. Despite several days of exploration, they have yet to find any ruins or artifacts that correspond to the Mayan civilization. Hungry archaeologists began to doubt the significance of the expedition, almost drowsy.
At this moment, someone stumbled upon a tunnel entrance that seemed to have been dug by hand! After seeing this discovery, the originally depressed archaeological team was immediately ignited by the flame of hope that was burning brightly. They scrambled to the entrance to the tunnel, hoping for some clue.
Upon entering the tunnel, the archaeologists were amazed by the sheer scale of the tunnel. The tunnel is tall and straight, and there are even branch tunnels on both sides. The inner walls of the tunnel are covered with faint scratches, which look like they were chiseled by animals.
The archaeologists were excited, but they couldn't help but be suspicious. Who built this one-of-a-kind tunnel? With such a huge amount of civil engineering, it seems that it was no longer possible for the Mayans to complete. And the age of the tunnel seems too old, according to some traces of the scene, it is speculated that this tunnel may even be tens of thousands of years old!
After this shocking discovery, the entire archaeological team members were excited, but at the same time, it pushed them into a whole new mystery. Who is the owner of this prehistoric project? What are the mysteries they hide? Archaeologists can only begin to work hard to unravel this mystery with full of doubts.
Mysterious creatures digging tunnels
Ever since the discovery of the massive prehistoric tunnel, archaeological teams have been working hard to unravel its mysteries.
First, they took a closer look at the scratches on the inner walls of the tunnel. The scratches are evenly spaced and regularly shaped, as if they were formed by some kind of creature repeatedly gouging into the rock with its own claws. Surprisingly, the distance between these scratches is the same, as if they were being dug according to a certain standard.
This phenomenon is of great interest to archaeologists. At the time, it was suggested that prehistoric humans were toiling on rocks with rudimentary tools. But soon, this statement was denied by everyone. This is because no traces of man-made tools or artifacts have been found in the tunnel, and they are so old that they seem to predate the known history of human civilization.
Archaeologists then turned their attention to other populations of organisms that lived on the South American continent at the time. After searching and comparing the ecological environment at that time, someone finally discovered a highly probable species - a giant prehistoric sloth.
According to geologists, the behemoth lived about 13,000 years ago and was tall and stout, covered in hair, hundreds of times larger than modern sloths. What's more, the structure of the sloth's claws closely resembles the scratches on the inner walls of the tunnel, suggesting that it was these creatures who excavated the tunnel in South America at the time.
To confirm this hypothesis, the archaeological team began searching the tunnels for other traces left by sloths. Sure enough, they found some intact fossilized sloth footprints in one of the corners of the tunnel. It can be seen that these giant sloth creatures must have moved freely through the tunnel at that time.
The length and size of the tunnels may seem huge, but it is not surprising for a more gregarious sloth population. Archaeologists speculate that the entire population may have worked together to carve out the tunnel little by little with its large claws.
As for the reason why the sloths dig tunnels underground, archaeologists have also given a reasonable explanation. It was during the Ice Age, when surface temperatures plummeted, and tropical sloths had to find a warm shelter. They chose to dig holes underground and use geothermal heat to maintain their body temperature to survive that cold period.
After careful analysis and argumentation by archaeologists, this statement seems absurd, but it is convincing. Otherwise, it would be difficult to explain why such a large-scale tunnel project took place. Humanity seems to have been far from mastering such capabilities at that time.
Characteristics and evidence of land sloths
Although it was only a bold conjecture at first, through further field investigation and analysis, the archaeological team became more and more convinced that those prehistoric giant tunnels were the masterpieces built by the earth sloths of that year.
The first is the dense scratches on the inner walls of the tunnel, neatly shaped and evenly spaced, which surprisingly match the construction of the sloth paws. Obviously, these traces are ironclad evidence left by the giant creature during the long excavation process.
Secondly, the structural layout of the tunnel is also extremely unique. The main road is straight and wide, and there are numerous branch tunnels on both sides, which are connected to each other to form a complex underground network system. This is in line with the characteristics of the land sloth habit of being more withdrawn and preferring to live in groups.
It is conceivable that these huge creatures may have worked together to expand their underground territory, with some digging in the main roads and others opening new branches on both sides to expand their underground territory. As a result, such a vast group of underground tunnels was gradually formed.
In addition, the archaeological team also found some supporting physical evidence in the depths of the tunnel. It was a well-preserved fossil of a giant creature and traces of a squirrel, and judging from the skeletal structure and body size, it was most likely the sloth of the earth.
Based on these clues, scientists have gradually painted a true picture of the land sloth. They are huge, up to 6 meters long, with a green body, rough fur, a strong waist and feet, and exceptionally well-developed claws. Obviously, it was with such a stout and powerful physique and sharp claws that they were able to carve out such a magnificent tunnel project in the hard rock.
So, why did the sloth dig such a massive tunnel underground? By analyzing the geological environment at that time, scientists came up with a possible explanation.
During the Ice Age, about 13,000 years ago, global temperatures plummeted, and even tropical regions were hit by icy cold snaps. As a creature that happens to adapt to the high temperature environment, the survival of the ground sloth has been severely tested.
Tunneling and new discoveries
In order to further verify the hypothesis of the construction of the tunnel by the sloth, the archaeological team decided to explore the interior of the tunnel.
They started by modeling the overall structure of the tunnel in 3D. It turned out that the combined length of these tunnels amounted to a staggering 8,000 kilometers! It is equivalent to digging a network of underground tunnels around the entire Earth's equator twice.
The structure of the tunnel itself is unique. In addition to its sheer scale, the tunnel does not extend in a straight direction, but winds and turns underground. Scientists explain that this structure is likely to increase the strength of the tunnel to withstand ground impact and weathering.
Surprisingly, at the corners of the tunnel, the archaeological team found some huge cavities with a diameter of more than 3 meters, which are suspected to be the nests of the earth sloths. These cavities are so large that they can accommodate the bodies of a dozen large giant beasts, so it's no wonder that the earth sloths were able to thrive here back then.
In the process of exploration, the archaeological team also found a large number of new fossils and biological traces, not only the ground sloth, but also the fossils of other kinds of creatures on the South American continent at that time, such as ancient tree species, bird footprints, huge earthworm caves and so on.
Based on these findings, scientists initially deduced that the South American continent at that time should have been an extremely fertile tropical rainforest environment, with a warm and humid climate and an unusually prosperous ecosystem. Countless creatures, including the earth sloth, thrive in such a unique environment, composing a glorious epic of life together.
However, it was at this time that a sudden global climate change pushed the glorious ecosystem to the brink of destruction.
According to geological chronology, about 13,000 years ago, the world entered a violent ice age, with temperatures dropping dramatically, and at least one-third of the land mass was covered with permanent ice and snow. Even the equatorial Amazon region has been severely damaged, with the rainforest environment severely damaged.
The cold killer and the struggle for survival
When extremely harsh cold weather hit, the ecosystems of the entire South American continent fell into an unprecedented crisis.
The tropical rainforest, which was originally warm and rainy, was ravaged by cold winds and snowstorms almost overnight. The dense trees were crushed by snow and ice, and the green meadows turned into barren ice fields. Countless insects and lower animals were the first to die in this weather change, and the upstream food chain was seriously threatened.
Even the massive sloth, which was supposed to be able to withstand the cold, suffered a devastating blow. The creature originally lived in a warm, humid environment and was defenseless. When the forest becomes a cold, barren land, their food source is completely cut off, and even the most basic living conditions are lost.
In the face of such ferocious weather, the earth sloths are also trying their best to survive. They gave up their territory on the ground, and entire populations began to migrate underground. Using their massive bodies and well-developed claws, they dug a vast network of tunnels into the ground, leaving their former shelter above the ground.
The underground is relatively warm and rich in geothermal heat, which alleviates the existential crisis of the ground sloth. But when they leave the ground, they also lose access to food. In order to survive, the sloths have to use up the last remaining fat in their bodies and struggle to survive.
The entire ice age lasted for tens of thousands of years. For the earth sloth, this is a protracted struggle for survival. Generations of individuals struggled to survive in the tunnels, huddling each other to keep warm with the last bit of strength until their last breath was exhausted.
Finally, after 10,000 years, the period of cold ice and snow is over. With the reawakening of nature, the ground is once again full of life. But those earth sloths who survived underground back then have lost signs of life one after another in the long and cruel struggle, and have become the eternal guardians of the underground world.