The work of giant animals: what kind of monsters created the ancient caves of South America (8 photos)
The lands of South America, especially the lands of Brazil, Argentina and Paraguay, are riddled with tunnels whose origin is questionable. Some of them are narrow passages with a diameter of 80-90 centimeters 
Bachelors actually live in such conditions and do not see any problem in this...
. Others are real underground bases with several rooms, the passages between which can be up to 4 meters wide, and the total length of the tunnels can reach 500 meters! Moreover, the number of mysterious tunnels is astounding: by 2016, more than 2,000 strange caves were known. Let's figure out who or what created them.
At first glance, it is clear that geological processes have nothing to do with it. The neat and straight corridors are cut through ancient, but relatively soft rocks and cannot be of volcanic origin. In addition, there is no trace of rock erosion. But curved grooves are still visible on the walls. As if the creators of the tunnels scraped the stone with something sharp. 
Someone did a good job here...
"They were people" - you will say, and you will be wrong. After all, we have a channel about animals! Research shows that the very first tunnels began to appear 3-4 million years ago, when Australopithecus just began to conquer Africa. The tunnels were made by completely different creatures, much larger and much more unusual... 
Like if you also loved making piles in snow as a child.
2014. General Alvarado District, Southeast Argentina. A group of researchers is studying another artificial cave and, unexpectedly even for themselves, discovers the skeletons of two of its inhabitants in one of the rooms - the skeletons of two giant sloths. And this discovery immediately explains all the oddities of the caves. Only a monster weighing 4 tons would need a man-made cave 2 meters high and 4 meters wide. Only sloths with their 15-20 centimeter long claws can leave such long and wide furrows on the walls. 
I wonder if you could ride them?
Unfortunately, to this day it is not entirely clear why they did this. Despite the fact that giant sloths were much more active than their modern relatives, they had a fairly low metabolic rate, and digging a tunnel was hard work for them. Probably, one cave was created by several generations of sloths at once. And it all started with simple depressions in the ground to create a shelter. 
Giant sloths were quite different from modern sloths, because their evolutionary paths diverged about 20 million years ago.
They most likely used underground bases to safely raise their offspring. After all, if an adult giant sloth was almost invulnerable to predators, then small young sloths were easy prey for any predator the size of a wolf. In addition, the stable climate of the burrows smoothed out the sharp temperature changes typical of South America during the Ice Age. 
Notice the sloth's conti. They are half the length of a woman's shin!
The last couple of paragraphs explain the existence of large burrows that a person can fit into without any problems. The small ones, about 1-2 meters in diameter, were clearly not dug by sloths. However, we have suspects here too: extinct giant armadillos, like Doedicurus. 
Just in case: in our universe, hitting Doedicurus and any other armadillos with bats is prohibited.
Even modern, relatively small armadillos dig tens of thousands of burrows every year and open the strong walls of termite mounds with the help of powerful claws on short but strong legs. Their larger and more powerful relatives could easily create shelters for themselves even in dense rocks! 
So why did I go outside? I guess I'll just keep playing computer games at home...
