At the beginning of the 21st century, South American scientists encountered mysterious and hidden underground tunnels. These underground passages deeply impressed the researchers, as they were not the result of human activity or a certain geological process. This discovery has generated significant interest throughout the scientific community, according to IFLScience.
Geology professor Heinrich Frank noticed an unfamiliar and unusual hole at the edge of the hill when he passed near a construction site in Brazil. Later, he returned and entered the inner part of the tunnel.
The passage stretched approximately 4.5 meters, and at its end, something even more unusual appeared that caught the scientist's attention: large nail marks were left on the ceiling and walls.
"There is no geological process in the world that creates long tunnels with circular or elliptical cross-sections, branching, rising and falling, with nail marks on the walls. "I have studied many inorganic caves, and in these cases, it is clear that animals did not participate in their creation," the professor said. His research showed that such complex structures could only be excavated by huge and powerful animals.
Evidence suggests that the secret creatures who dug these tunnels were giant sloths who perished and lived 8,000-10,000 years ago. Compared to modern sloths, they move much slower and are lighter, but prehistoric creatures were equal to African elephants and possessed the strength necessary to dig large tunnels.
In the Brazilian region of Rio Grande do Sul, Frank and his colleagues documented more than 1,500 such ancient underground passages. The longest among them stretched approximately 600 meters and had sufficient width for humans. These tunnels were probably dug by groups of lazybones for several generations.
In 2018, a study analyzing 200 petrified tracks in Utah showed that humans and sloths were in close contact with each other, and this is supported by evidence pointing to harassment and hunting.
