King of Cretaceous Carnivores

In its time, Tyrannosaurus rex was the largest meat eater in western North America. It feasted on dinosaurs large and small—including Triceratops, as seen here—gulping down flesh and bone in massive bites. Weighing in at more than 15,000 pounds and 42 feet long, no other carnivore could touch the “king of the tyrant lizards” (as its name means in Latin). This skeleton, found in 1988 by a Montana rancher, includes the first complete T. rex arm ever recovered. How T. rex used its puny arms remains a mystery, but the beast had more formidable weapons, such as thick, serrated teeth that could crush its prey’s bones.

An ancient reptile resembling long-snouted, fish-eating modern crocodilians, Champsosaurus laramiensis filled a similar ecological role in its environment. Champsosaurus survived for 30 million years after the end-Cretaceous extinction.

The alligator Stangerochampsa snagged prey with its front teeth and crushed bones with its rear ones. It died out with the dinosaurs.

The six-inch-long serrated tooth of Tyrannosaurus rex could cut like a steak knife.