For some mammals, the evolutionary path to gigantism after the dinosaurs’ demise wasn’t always a straight road. Species of extinct, hefty, rhinoceros-like creatures called brontotheres evolved into ...

Breakthroughs, discoveries, and DIY tips sent every weekday. Terms of Service and Privacy Policy. After an asteroid that wiped out the dinosaurs struck the Earth, the ...

In the aftermath of the dinosaur-killing asteroid impact, a second explosion rocked the animal kingdom. This time, it was the mammals that blew up. Rhino-like horse relatives that had lived in the ...

At the end of the Triassic period, small-sized dinosaurs roamed Earth alongside other groups of archosaurs—that is, until a widespread extinction event cleared the way for dinos to put on some serious ...

Editor’s Note: Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more. Very large things often have small ...

The fossil record is filled with with land animals who grew to impossibly large sizes. Brontotheres, the ancient North American ancestors of the horse, is a giantism outlier as—growing from around 40 ...

Very large things often have small beginnings. That certainly was true for brontotheres, the enormous, rhino-like herbivorous mammals that lumbered across North America and Asia during the Eocene ...

Very large things often have small beginnings. That certainly was true for brontotheres, the enormous, rhino-like herbivorous mammals that lumbered across North America and Asia during the Eocene ...