More than 65 million years ago, the Montana landscape was very different than it is today. A large inland sea covered much of the area that is now Montana. It created a semi-tropical flood plain not unlike the Everglades of Florida today.
During the last days of the dinosaurs, large herds of these massive beasts lived, migrated and nested in the upland areas surrounding the shallow sea. Duckbill dinosaurs and horned dinosaurs known as Triceratops are two of the plant eating varieties that inhabited the area.
The Triceratops was a herd animal; it is believed that large groups roamed North America. Their large beaks and long rows of teeth were well designed for chewing tough, low growing plants. It was likely the main predator of these animals was the Tyrannosaurus rex which means "tyrant lizard". A number of skeletons show bite and chew marks that match the teeth of T. rex.
The Central Montana's portion of the Montana Dinosaur Trail includes the following sites at Bynum, Chinook, Choteau, Havre, Harlowton and Rudyard.