Have you ever hear of a Rhino roaming the plains of Wyoming? If not, that’s because they haven’t been alive on this continent for a very long time. In fact, the Running Rhino last walked through the Americas in the Oligocene period. These large grazing mammals benefited greatly from the growing grass lands that began to sprout up as the tropical jungles of the Eocene epoch. Not a tramendous amount is known about the Running Rhino. But they grew to be some 7-9 feet long and weighed 900 lbs, making them substantially smaller than the Rhinos of Africa. Because they did not have a nose horn, it is believed that these herbivores relied on their speed as a method of self defense. However, there is also some question about how much they needed to use this defense as they were one of the largest mammals of their time.

How do you measure up?

About the Fossil:

Name:	Running Rhino (Subhyracodon)
Fossil Type:	Skull
Age:	32 million years (oligocene period)
Location:	Converse County, Wyoming, White River Formation
Size:	15.4 inches