The story
Yutyrannus huali, described by Xu Xing and colleagues in 2012, is a tyrannosaur about 9 m long and about 1.4 tonnes from the Yixian Formation of Liaoning, China. Three specimens, found together, preserve long filament-like feathers up to about 15 cm long. Its name means beautiful feathered tyrant. It lived about 125 million years ago, some 60 million years before Tyrannosaurus rex.
Until then, the known feathered dinosaurs were small, mostly chicken- to dog-sized. Yutyrannus is many times heavier, so feathers could not have been used mainly for flight. Their likely roles were warmth and display: the Yixian climate was cool, with a mean annual temperature estimated around 10 C. The find raised the question of whether T. rex also had feathers as a young animal. Skin impressions from the adult T. rex show scales on parts of the body, so adults probably lost most of their feathers.
Why it mattered
- Yutyrannus showed that a very large predatory dinosaur could still be feathered.
- It supports the idea that feathers evolved first for insulation and display, not flight.
- It prompted restoration of tyrannosaurs, including the young of Tyrannosaurus rex, with more fuzz.
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