Were dinosaurs warm- or cold-blooded? New research may end the debate with an answer from dinosaur eggshells.

Volcanoes had nothing to do with K-Pg, the mass extinction event in which dinosaurs perished, researchers say. That was all an asteroid's doing.

New research indicates climate warming and mercury contamination at the time of the Deccan Traps volcanism.

"These fossils tell us for the first time how exactly our planet recovered from this global cataclysm."

"The T. rex had a skull that's 6 feet long, 5 feet wide, and 4 feet high, and bites with the force of about 6 tons."

"It was a momentous day in the history of life, and this is a very clear documentation of what happened at ground zero..."

Alligator skulls suggest how the Tyrannosaurus rex kept itself from overheating with two holes in its head.

"When I first saw this animal back in 2004, I knew instantly it was a new kind that had never been seen before and was very excited about it."

New fossil evidence of mammals from the time of the dinosaurs "overturns a classical interpretation of how mammals evolved."

A new dinosaur "gives us a glimpse into the evolution of tyrannosaurs just before they take over the planet."