Menoceras arikarense

Click here to see muscles and bones

North America used to be a major stronghold of the rhino clan up until about five million years ago. The pig-sized Menoceras roamed the plains of the mid-west during the Arikareean land mammal age of the lower Miocene epoch. Because of the massive accumulations of fossil bones of this animal, particularly at Agate Springs Nebraska, it seems safe to assume that they lived, and died in large herds.

Menoceras belonged to the genus Dicerorhinus whose only surviving member is the endangered Sumatran rhino. Male Menoceras sported two horns side by side at the tip of the nose, whereas the females had no horns. All other rhino genera have their horns arranged one behind the other.

This illustration shows a male Menoceras trotting up from the water hole, while a Paleocastor squawks  his protest over the tresspass.

Paleocastor is an ancestor of the modern day Beaver. The filled-in remains of their burrows are abundant in lower Miocene deposits of Nebraska. Also known as Daemonelix or "devils corkscrews" their origin remained a mystery until many paleocastor remains were eventually found in the living chamber at the bottom of the corkscrews.

 This painting is on display at the Science Museum of Minnesota.