



Did Tyrannosaurus rex have feathers? The answer may surprise you!The answer is:Surprised? You shouldn't be. We only have a few small patches of tyrannosaurid skin from different parts of the body described so far (Bell et al. 2017), and we don't really know much about the interplay of feathers and scales (or reticulae, if you want to get into specifics) in coelurosaurian theropods. While there are good reasons to believe some feathers were present on Tyrannosaurus, the possibility remains that it had, for whatever reason, completely given up feathers the same way large ornithopods seem to have done.However, you can't just simply replace all the feathers on old rexy and be done with it. Tyrannosaurus persisted in a climate with a mean annual temperature of about 11 °C, which means it had to periodically deal with some unpleasantly cool temperatures for an uninsulated animal. How could scaly Sue survive in such an environment? The answer could be by getting fat. An insulating layer of blubber lets marine mammals to do without hair and appears to have enabled sauropterygians to thrive in frigid waters. Perhaps the scaly tyrannosaurids of yesteryear's paleoart aren't that inaccurate, they're just way too thin!This illustration aims to portray Tyrannosaurus rex (based on the Sue specimen, from a skeletal drawing by) the way it might have looked if it lacked feathers entirely (there are still some short quill-like highly modified ones left on the neck and arms, perhaps for display purposes or to discourage biting). Of course in the case of Tyrannosaurus, the scales are probably modified feather as well. The small patches of skin from Tyrannosaurus specimens show that the scales were so small, you'd have to get very close to the animal to actually see them. The "lumpy" look of Sue's face is based on Carr et al. (2017), who mention correlates for armor-like skin on several parts of the skull in Daspletosaurus, a close relative and possibly even a direct ancestor of Tyrannosaurus. Though very plump, Sue still has some loose skin folds around the neck and torso, as these regions need to be able to stretch to allow the swallowing of large food items and to engorge on a kill, that would presumably produce an even more rotund creature (while the meal is being digested anyway).Sources/Further reading:Bell et al. (2017) Tyrannosauroid integument reveals conflicting patterns of gigantism and feather evolution Carr et al. (2017) A new tyrannosaur with evidence for anagenesis and crocodile-like facial sensory system Arens and Allen (2014) A florule from the base of the Hell Creek Formation in the type area of eastern Montana: Implications for vegetation and climate