Megatherium americanum was one of the largest species of ground sloth, a group of closely related animals once common in the Americas, particularly South America. Its scientific name translates as ‘a big animal from America’.There were once many different kinds of ground sloth but all are now extinct. They were a widespread and successful group of mammals - their fossils have been found from Patagonia to Alaska. The last ground sloths seem to have died out about 10,000 years ago when humans colonised the Americas.