Look up any dinosaur, and chances are you will soon come across an estimate for how long it was. And chances are that estimate is wrong. That’s because, as Dave Hone from University College Dublin points out, our knowledge of dinosaur tails is woefully inadequate.

After searching through papers, museum collections, photos, and the minds of his colleagues, Hone found that among the thousands of dinosaur specimens that have been found, there are “barely two dozen complete tails”. These range from animals like Spinosaurus, where virtually no tail fragments have been found, to others where skeletons are missing an unknown number of vertebrae from the tips. Even in complete skeletons, Hone’s research showed that closely related species, and even individuals, can