Brontotheres were rhino-like animals which bony, horn-like prominences on the front of their heads. They lived from 53 million years ago until 34 million years ago and were among the first, large, plains-living animals to evolve when North America’s Great Plains forests started to open up about 40 million years ago.
While Brontotheres look somewhat like a rhino, they are really more closely related to horses. They have four toes on their front feet and three toes on their hind feet. Their teeth are adapted to cutting nonabrasive vegetation.
Shown below are the Brontotheres displays in the Raymond M. Alf Museum of Paleontology on the campus of the The Webb Schools, a private residential high school, in Claremont, California.
Each time a brontothere skull was found, the discoverer got to name it. Hence the names of the skulls displayed.
With regard to the horns, the Museum display reports:
“Most paleontologists think that the horns were used in mating displays or wrestling matches. They speculate that males had larger horns than females.”
According to the museum display:
“We don’t know how these brontotheres from Wyoming died, but we do know that their bones were scattered by scavengers or water and left lying on the ground a while before burial and fossilization. At least three animals are here, because parts of three different skulls are present.”