The classic view of Tyrannosaurus rex as a large and scaly dinosaur may be correct, scientists say, after some had suggested it may have had feathers.
Ever since T. rex graced our screens, most notably in 1993’s Jurassic Park, debate has raged as to what it really looked like. In 2012, the discovery of a giant tyrannosaur with feathers, Yutyrannus, lent credence to the idea that T. rex might also have been fluffy.
Not so, say researchers writing in the journal Biology Letters. They say they’ve found evidence for fossilized scaly skin on a variety of tyrannosaur species, including the T. rex, that supports the idea they had a reptilian-like appearance.
“These new findings demonstrate that extensive feather coverings observed in some early tyrannosauroids were lost,” the team wrote in their paper, led by paleontologist Dr Phil Bell from the Pipestone Creek Dinosaur Initiative in Alberta, Canada.
To make the findings, they looked at a variety of fossils, including the partial skull and skeleton of a T. rex. They also studied skin from other Late Cretaceous (100 to 66 million years ago) tyrannosaurids. In all the samples, the team found only scales, and no evidence of feathers.
Yutyrannus, which existed about 125 million years ago, was an ancestor to the T. rex, alive from about 85 to 66 million years ago. Thus, the discovery of feathers on the former suggested T. rex had a similar appearance.
These findings, however, suggest that if T. rex did have any fluff, it was likely confined to a small portion of its back. The rest of the beast resembled the fearsome creature that terrorized our screens in Jurassic Park.
Not everyone is fully convinced just yet, though. Matthew Baron, a paleontologist from the University of Cambridge told IFLScience that there is still a chance T. rex was “fluffy” and that “some, if not all, of the animal's body may have supported some feathery structures.”
“The presence of fossilized scales does not strictly prohibit the possibility that some feather-like structures remained on parts of the animal’s body," he said. "Think of an ostrich: feathery body, mainly, but with scaly legs.”
However, Bell noted to IFLScience that the samples available at the moment – namely skin of the belly, hips, and tail – are all scaly. “What the naysayers point out is that we don't know what's happening on the head or legs or back,” he said. “Maybe they had feathers, maybe they didn't. But right now all signs point to scales.”
If the scaly idea is correct, one key question remains: How and why did the tyrannosaurs lose their feathers? One possibility is that increased activity or higher athletic performance could have caused hair loss. Or it might be they were simply too big to shed enough heat with feathers.
“Possibly the loss of feathers is related to gigantism; big animals have trouble shedding excess heat, so having feathers is not a good idea because they are good insulators,” said Bell. “It's a reasonable theory, but there's more that we don't know than what we do.”