Billions of Tyrannosaurus rex roamed North America during their fascinating reign as top predators, according to a team of researchers that went about the daunting task of making the calculation.

One Tyrannosaurus rex seems scary enough. Now picture 2.5 billion of them. That’s how many of the fierce dinosaur king probably roamed Earth over the course of a couple million years, a new study ...

A legendary fossil housed at the North Carolina Museum of Natural Sciences in Raleigh features skeletons apparently locked in prehistoric combat — an epic meeting of two of the world’s favorite ...