Tucson Scientists Unveil Ancient Footprints of Colossal SlothsTucson Scientists Unveil Ancient Footprints of Colossal Sloths In a groundbreaking discovery, scientists at the University of Arizona in Tucson have unearthed a remarkable series of ancient footprints left by giant sloths that roamed the Sonoran Desert millennia ago. The footprints, belonging to the extinct genus *Paramylodon*, were found at the Rancho Pensamiento archaeological site on the outskirts of Tucson. They range in size from approximately 12 inches to over 2 feet in length, indicating the presence of massive sloths that dwarfed their modern counterparts. “These footprints provide a glimpse into a time when the Sonoran Desert was a lush, subtropical environment that supported diverse megafauna,” said Dr. Emily Lindsey, lead author of the study published in the journal Quaternary Science Reviews. The footprints were found in a layer of sediment that dates back to the Late Pleistocene epoch, approximately 13,000 to 50,000 years ago. This was a period of significant environmental change, with major shifts in climate and vegetation. Examination of the footprints revealed that the sloths walked in a plantigrade manner, with the entire sole of their foot touching the ground. The footprints also exhibit characteristic claw marks, which provide insights into the anatomy and behavior of these extinct animals. “The footprints suggest that these giant sloths were herbivores that walked on their hind legs, using their powerful forelimbs to reach up and grasp branches from trees and shrubs,” said Dr. Lindsey. The discovery of these footprints has shed new light on the paleoecology of the Sonoran Desert during the Late Pleistocene. It adds to the growing body of evidence that the Southwest was once home to an astonishing array of megafauna, including mammoths, mastodons, giant ground sloths, and saber-toothed cats. “These footprints are a testament to the incredible biodiversity that once existed in our region,” said Dr. Lindsey. “They serve as a reminder of the dynamic and ever-changing nature of our planet.” Further research on the Rancho Pensamiento footprints and the surrounding environment is expected to provide valuable insights into the ecology, behavior, and extinction of giant sloths in the Sonoran Desert.