In the ancient badlands of North Dakota, the earth has finally yielded what generations of paleontologists could not find: the walking signature of an adult Tyrannosaurus rex. The trackway — with its surprisingly human-scaled footprints and 13-foot strides — offers something no skeleton ever could, a record not of what the creature was, but of what it actually did. It is a reminder that the deepest truths about living things are often found not in their bones, but in the marks they leave behind.