An illustration shows what Duonychus tsogtbaatari might have looked like. Unlike its therizinosaur brethren, the new species ...

Dinosaurs are the extinct relatives of birds that roamed the lands and seas of ancient Earth. They first appeared around 240 ...

Fossils of alvarezsaurid dinosaurs show bird-like air sacs in their bones. Scans revealed hollow spaces connected to their ...

"We see this cascade of changes that happened along the dinosaur to bird transition," Holliday said. "A large part of it hinges upon when birds evolved a relatively large brain. Just like in ...