Few questions start more arguments at a museum than this one. The short answer: the closest relatives of Tyrannosaurus rex had feathers, but the fossil skin we have from T. rex and its big cousins shows mostly scales. Here is how scientists know.
Tyrannosaurs started out feathered
Tyrannosaurs were not always giants. Early members of the family were small, lightly built hunters, and some of them were preserved with feathers. Dilong paradoxus, a small tyrannosauroid described from China in 2004, was found with simple, hair-like filaments, a primitive kind of feather.
Then, in 2012, came Yutyrannus huali, also from China and about 125 million years old. It was big, around 9 meters long, and it was covered in long filamentous feathers. That find proved that even large tyrannosaur relatives could be fluffy. One idea is that the feathers helped keep it warm in a cool climate.
But T. rex skin shows scales
Fossil skin is rare, but in 2017 a team of paleontologists described skin impressions from Tyrannosaurus rex itself and from several close relatives, including Albertosaurus, Daspletosaurus, Gorgosaurus and Tarbosaurus. The patches came from the neck, hips and tail, and every one of them showed small scales, not feathers.
Their conclusion: the giant tyrannosaurs of the Late Cretaceous were mostly scaly. If T. rex had any feathers at all, they were probably limited to small areas such as the back, and we have no fossil evidence for them yet.
Why would a giant lose its feathers?
One common explanation is size. A seven-ton animal produces a lot of body heat and has relatively little skin surface to lose it through, so a thick coat of insulation could have been more of a problem than a help, much like elephants today have very little hair. This is a hypothesis, not a settled fact, and new fossils could still change the picture.
The other big update: lips
Movies show T. rex with its teeth permanently on display. A 2023 study comparing tooth wear, jaw anatomy and living reptiles argued that theropods like T. rex most likely had scaly lips that covered their teeth when the mouth was closed, the way lizards do. That is why our Plate 001 shows a T. rex with its teeth hidden.
See the evidence in our art
Every plate in the Deep Time Atlas is reconstructed from fossil evidence and published research. Compare the scaly Tyrannosaurus rex Moonlight tee with the feathered Yutyrannus Cold Forest tee, two cousins that tell the whole story side by side, or browse all T. rex, raptors and predators.