You probably know already that birds are descended from dinosaurs. It’s been well documented that dinosaurs, rather than being run-of-the-mill reptiles, were quite different to lizards or crocodiles. For a start, dinosaurs’ legs were beneath their bodies, whereas most reptiles have their legs splayed to the side. It’s also believed that dinosaurs were warm-blooded but reptiles are cold-blooded creatures. Finally, we know that many dinosaurs had feathers – not for flight, but to help keep them warm.
It has been thought for a long time that the most famous dinosaur of all, Tyrannosaurus Rex, also had feathers – although no T Rex fossil has yet been found with any evidence of feathers. There are a couple of reasons this might be – either they never had feathers or (just as likely), as soft body parts, feathers seldom become fossilised. Added to that, the fact that we’ve not found very many preserved Tyrannosaurs, casts doubt on the whole question.
Why then do most palaeontologists (those who study fossils) think that T Rex had feathers? Well, we have found feathers on some species of dinosaur very closely related to T Rex. Dilong paradoxus was an ancestor of T Rex which lived 60 million years or so before it. Fossils of Dilong paradoxus have a covering of simple feathers quite different to modern bird feathers, which were used to insulate them – just like modern mammals use fur. If its ancestors had feathers then surely T Rex itself did? Maybe – but it ain’t necessarily so!
The thing about Dilong paradoxus is that it was small – about the size of a dog. Small animals need to keep warm as they lose heat easily. Larger animals on the other hand, like T Rex, have more of a problem trying to stay cool. Just think of today’s largest land animal, the elephant. It’s smaller than a T Rex and it’s lost most of its fur in order to stay cool.
Wanting a final answer to the fluffy T Rex question, researchers have done a study of skin impressions on T Rex fossils. What they found, they believe, is scaly reptilian skin with no sign of feathers at all. This suggests that T Rex, just like the elephant, lost its layer of insulation as it got bigger.
Not all scientists are convinced by this theory, and there is a third option. Many animals change their appearance as they grow into adults. Young Tyrannosaurs would be prone to cold weather, just like their smaller ancestors. Perhaps baby T Rex had feathers which he lost as he grew up?
As is the way with science, there are many theories. All we can do is look at the evidence and use it to try and find the truth. Whether or not T Rex was fluffy may be a question we just can’t answer – well, not unless we find a way to either travel back in time to see for ourselves, or use DNA and cloning techniques to create a living T Rex in the lab. But both of these solutions add brand new problems of their own!
If you love science (or dinosaurs!) then take a look at Education Quizzes. There are science quizzes for every age group and free-to-play specialist quizzes too, like these ones on Nature. There really is something for everyone – why not take a look?