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 ...

We know dinosaurs were big, but how big were they? And how do we even know? Luckily, paleontologists and other scientists know how to find the answers. By measuring fossils, comparing them to the ...

Thunder beasts were among the first mammals to truly live large. The biggest of these rhino-like creatures, called brontotheres by experts, stood taller than eight feet at the shoulder and weighed ...

Paleoartist Roman Uchytel has created a gallery of size-comparison images that highlight the radical evolutionary journey that modern day animals have undergone when compared to their long-extinct ...

Researchers have unearthed the remains of a new species of gigantic marine turtle in northern Spain. Weighing about two tons and measuring 12 feet long, the prehistoric creature is the largest of its ...

Scientists have used a combination of ancient fossil remains and the scans of a great white shark to create a 3D model of a prehistoric megalodon. Armed with this model, the researchers figured out ...

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 ...

CNN — 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 ...