Do you know what kind of animal is on the National Fossil Day logo? Although it looks like a furry rhinoceros, it is a titanothere. Titanotheres are in a completely different family than rhinos. They are now extinct.
Titanotheres, also called brontotheres, were herbivorous, odd-toed ungulates (hoofed mammals) that lived during the Eocene between about 50 and 34 million years ago. Although the earliest titanotheres were relatively small, perhaps dog-sized, titanotheres eventually reached elephant-size, standing more than 2.5 meters (7 feet) tall! In addition to their large size, the later titanotheres also displayed a variety of bony, usually paired, appendages on the front of their skulls. These appendages may have been used for defense or to attract mates.
Titanothere fossils are mostly from North America, although some have been found in Asia. Titanothere fossils are so abundant within and surrounding Badlands National Park (South Dakota), that early paleontologists referred to the layers as the "titanothere beds." Those beds are now considered part of the Chadron Formation. Titanotheres went extinct at the end of the Eocene.
Global climate, already cooling for much of the Eocene, was cold enough at the end of the Eocene (34 million years ago) that permanent ice had formed on the south pole. This transition from a warm, lush "greenhouse" climate to a colder, drier "icehouse" led to a great reduction in the nearly-tropical ecosystems titanotheres called home.
Last updated: November 3, 2016