A quote from Walking on Eggs: "...coelurosaurs were feathered; even the colossal Tyrannosaurus must have had a feathered body at some early stage of its life. However, scientists do not believe that adult tyrannosaurs were feathered because the combination of this insulating covering and their large size might have posed a disadvantage in regulating the animal's body temperature."
OK, can anyone tell me what this belief is based on? Is there sound scientific evidence for it, or is it conjecture?
Thanks to anyone who can help!