It’s a Bird! It’s a Plane! It’s a…Tyrannosaurus Rex?

Did Tyrannosaurus rex, the most famously terrifying dinosaur there is, look like a chicken?

It’s a question that has been circling around the field of paleontology for quite some time now. Well, maybe not the question of whether or not Tyrannosaurus looked like a 13-meter-long bloodthirsty chicken. Instead, paleontologists have questioned as to whether or not Tyrannosaurus had feathers or reptilian scales. Before you laugh off this seemingly ridiculous notion, let me present the arguments for and against this theory.

The theory of a feathered Tyrannosaurus stems from the fossils of two early tyrannosaurid species: Dilong and Yutyrannus. Dilong – which is less than two meters long and would have weighed about the same as my Cavalier King Charles Spaniel – is far from what you might expect to be a tyrannosaur. Nonetheless, Dilong represents an early genus of the tyrannosaur lineage that displays various forms of feathers along the tail and jaw, with more likely found across the body. The protofeathers of Dilong shows that feathers were a trait that, at some point, could be found within the tyrannosaur lineage.

The issue with using Dilong’s feathers to argue that Tyrannosaurus’ had them too is the notable difference in their sizes. Larger animals experience more difficulties with heat regulation than their smaller counterparts, which has led some paleontologists to theorize that the tyrannosaurids lost their feathers as they became the dominant predators across the northern hemisphere. The presence of feathers on Dilong, a dinosaur about the same size as Tyrannosaurus’ hatchlings, cannot be used to assert their presence on Tyrannosaurus.

However, Yutyrannus is different. At about ten meters long and weighing over a tonne, Yutyrannus represents a large genus and (at the moment) the largest confirmed feathered dinosaur. With such a large size, the overheating argument quickly goes out the window, as Yutyrannus’ environment of Cretaceous China was prone to humid summers seemingly unfit for a large, feathered dinosaur.

That’s not all. Dilong and Yutyrannus both come from the Yixian formation of Liaoning China and date to the same time during the early Cretaceous period. Their presence alongside one another means that feathers were not present on a specific branch of the tyrannosaurid lineage; rather, they appear to be a common trait in the family. If this is the case, then it would indicate that Tyrannosaurus and other genera such as Tarbosaurus and Albertosaurus all may have had feathers.

There is one flaw with this theory: no specimen of Tyrannosaurus – or Tarbosaurus and Albertosaurus for that matter –  has any traces of feathers. Fossilized scales are present on specimens of multiple advanced tyrannosaur species that make up most of the body, yet they contain no evidence of feathers. This lack of adequate material may change in the future as more specimens are dug up, but at the moment, the notion of a feathered Tyrannosaurus may be in jeopardy.

Except it isn’t. Taking specimens from multiple species spread across two continents and millions of years is a flawed way to eliminate the possibility of feathers for the whole family tree given that they are different animals and therefore have different patterns of skin and feathers. Additionally, there is virtually no fossil material on the skin of juvenile tyrannosaurids, so it is entirely possible that Tyrannosaurus started its life fluffy then grew into the scaly monster we are all familiar with. So while some will continue to undermine this theory, it is highly likely that Tyrannosaurus had feathers at some point in their lives.

Besides, feathered dinosaurs make paleoart way more engaging and awesome.

For such a seemingly innocent topic, this debate has racked up a lot of controversy. Take for example this article that I found in my research process that is strongly opposed to the notion of a feathered T-rex. It’s a good article that I recommend reading, but man the hatred of a feathered Rex is strong with this one. In another article I read, the author said he would have “cried” at the notion of a feathered Tyrannosaurus when he was younger.

I understand where this distain is coming from – to an extent. Most people grew up on the notion that dinosaurs like Tyrannosaurus and Triceratops looked like giant reptiles, so to suddenly be told that they may have looked like giant peacocks would surely come as a shock. A big one.

Some of my friends at school said it best. When I broached them with the notion that Tyrannosaurus may have been feathered, they told me that I “ruined their childhood.”

Talk about overly sensitive, am I right?

Works Cited

I do not take credit for any images in this article.

Header Tyrannosaurus courtesy of Franz Anthony, original source found here

Baby Tyrannosaurus courtesy of Julius Csotonyi, found here

Yutyrannus courtesy of Robert Powell, found here

1. Brusatte, Stephen. The Rise and Fall of the Dinosaurs: a New History of a Lost World. Thorndike Press, 2019.
2. Hecht, Jeff. “T. Rex Descended from Feathered Ancestor.” New Scientist, 6 Oct. 2004, http://www.newscientist.com/article/dn6500-t-rex-descended-from-feathered-ancestor/.
3. Katz, Brigit. “T. Rex Was Likely Covered in Scales, Not Feathers.” Smithsonian.com, Smithsonian Institution, 8 June 2017, http://www.smithsonianmag.com/smart-news/t-rex-skin-was-not-covered-feathers-study-says-180963603/.
4. Tarlach, Gemma. “Just Say No To Feathered Tyrannosaurs.” Discover Magazine, Discover Magazine, 23 May 2020, http://www.discovermagazine.com/planet-earth/just-say-no-to-feathered-tyrannosaurs.
5. Pilcher, Brandon S. “Why Tyrannosaurs Probably Didn’t Have Feathers After All.” Medium, The Startup, 8 Jan. 2020, medium.com/swlh/why-tyrannosaurs-probably-didnt-have-feathers-after-all-e0d91457d53b.
6. Hone, David. The Tyrannosaur Chronicles: the Biology of the Tyrant Dinosaurs. Bloomsbury Sigma, an Imprint of Bloomsbury Publishing Plc, 2017.