These massive tunnels found in Brazil are called paleoburrows and were likely dug by extinct giant ground sloths over ten thousand years ago. These animals used powerful claws to excavate long underground passages for shelter and protection. Distinct parallel grooves on the walls match claw marks rather than geological processes, helping scientists confirm their origin and understand prehistoric ecosystems. Such structures can stretch for hundreds of meters, revealing surprising engineering abilities of these slow moving mammals in ancient South America. Source: Frank, Henrique T., et al. “Paleoburrows and Paleocaves in Southern Brazil.” Journal of South American Earth Sciences. Want more interesting content like this ? Follow gravitonomy :) Via : Unknown No copyright infringement intended. Kindly DM for Credit/Removal/Collaboration :) #giantsloth #science #caves #history #wildlife