"It's a juvenile, or teenage, gorgosaurus … that had eaten two young and small birdlike dinosaurs called Citipes." Gorgosaurus was a tyrannosaur that lived 75 to 77 million years ago, before the ...

Birds and non-avian dinosaurs are categories created by us, but in reality there’s no clear line distinguishing the two. Over millions of years, birds evolved signature features that collectively set ...