What Dug this 10,000 Year old Burrow?

Giant Sloths? Giant Armadillos? They’re called paleoburrows, they’re 10,000 years old, and Brazillian geologist Heinrich Frank and his students are trying to figure out what dug them. Here’s more from Discover Magazine:Surveying a 45-mile stretch of highway construction near the city of Porto Alegre, for example, Frank and his students...