Humongous fuzzy dinosaur unearthed in China (+video)
An ancestor of Tyrannosaurus rex, Yutyrannus huali weighed 3,000 pounds and was covered in a downy fuzz.
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The researchers discovered fossils of the dinosaur's feathers and were able to clearly make out that the large dinosaur was one shaggy predator.Skip to next paragraph
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"The feathers of Yutyrannus were simple filaments," Xu said. "They were more like the fuzzy down of a modern baby chick than the stiff plumes of an adult bird." The hairlike feather filaments were about 6 inches (15 centimeters) long and probably covered the majority of the animal's body.
The feathers weren't used for flight, but to keep the giant lizard warm, an interesting adaption in dinosaurs, a group typically thought of as "cold-blooded," Xu said.
"The idea that primitive feathers could have been for insulation rather than flight has been around for a long time," study researcher Corwin Sullivan, a paleontologist at the Chinese Academy of Sciences, said in a statement. "However, large-bodied animals typically can retain heat quite easily, and actually have more of a potential problem with overheating. That makes Yutyrannus, which is large and downright shaggy, a bit of a surprise."
The explanation may be climate-related, the researchers say. While the Cretaceous Period was generally very warm,Yutyrannus lived during the middle part of the Early Cretaceous, when temperatures are thought to have been somewhat cooler than the Late Cretaceous, when T. rex lived.
The study was published today (April 4) in the journal Nature.
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