Look at the fossil remains of this ancient creature and you might believe you're looking at a giant bear. In fact, these elephantine animals were ground sloths, most closely related to the slumbering modern-day three-toed sloth. They make good candidates for resurrection because they went extinct so recently — giant ground sloths may have still walked the Earth just 8,000 years ago at the dawn of human civilization. DNA samples have already been extracted from intact hair remains.
Because the only surviving relatives of the ground sloth are tiny by comparison, finding a surrogate mother is impossible. But it may someday be possible to develop a fetus in an artificial womb.