Scientists have uncovered tyrannosaurus rex bones in the areas of western North America. Paleontologists have uncovered bones in Canada, Wyoming, Utah and Montana.
Before the continents stood where they stand today, dinosaurs roamed around an island called Laramidia. Geological changes, including the rise of mountain ranges and the expansion of the sea, caused the tyrannosaurus rex to become enclosed in the area of what is now western North America.
Dinosaurs caught on the southern part of the mountain ranges may have ventured into areas of South America. Those caught on the northern part of the mountain ranges may have ventured to Asia by way of Alaska.