The huge birds that lived in North America could take the saying, "I'm so hungry I could eat a horse," literally during the Eocene. Diatryma was one of these birds, along with Phororhachos and many others. Diatryma and its relatives were colossal flightless birds with parrot-like beaks and tremendous claws. It was almost seven feet tall, and since flying was too energy consuming for it, it had to run - especially after horses. These birds of terror died out when mammalian carnivores invaded their habitat. Apparently, the newcomers overpowered the birds. Despite this change, horses became none the better off. They were still terrorized by the other carnivores.

Cenozoic Era: Tertiary Period: Eocene Epoch: Creature Feature