Uintatherium

Uintatherium ("Beast of the Uinta Mountains") is an extinct genus of herbivorous mammal that lived during the Eocene epoch; two species are currently recognized, U. anceps from the United States during the Early to Middle Eocene, and U. insperatus of Middle to Late Eocene China. Uintatherium went extinct about 37 million years ago, presumably due to climate change and competition with perissodactyls, such as brontotheres and rhinos.

Uintatherium was a large browsing animal. With a length of about 4 m (13 ft), a height of 1.70 m (5.6 ft), and a weight up to 2.25 tons, they were similar to today's rhinoceros both in size and in shape, although they are not closely related. Its legs were robust to sustain the weight of the animal and were equipped with claws. Moreover, unlike the rhinos today , the sternum was made ​​up of segments of Uintatheres horizontal planes, and compressed and vertical segments.

As with other early mammals of the Eocene epoch, Uintatherium didn't exactly excel in the intelligence department, with an unusually small brain compared to the rest of its bulky body.