One day 66 million years ago, life came to a sudden, apocalyptic halt when an asteroid impact violently closed the book on the age of dinosaurs. Birds are the only members of the dino family tree that survived the ordeal, and the open niches left behind gave them and our early mammal ancestors their time in the ecological spotlight.

But what if calamity hadn't befallen the dinosaurs? Would they still have gone out not with a bang, but a whimper?

Maybe not, according to a new study that says dinosaurs still had plenty of vim and vigor leading up to the mass extinction at the end of the Cretaceous period. Revealed using huge simulations that are new to