National Fossil Day   Explore Nature
National Park Service
US Department of the Interior

What's on the logo?

The National Fossil Day logo features a titanothere. Download the logo here.

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.

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Titanotheres lived in open areas close to the nearly-tropical forests common in western and central North America during the Eocene. They were browsers, meaning they fed on leaves of trees or shrubs. Image courtesy of Badlands Natural History Association.

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.

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Dr. Hiram Prout, a St. Louis physician, described this titanothere jaw in 1846. It was the first scientifically described fossil specimen from the American West and discovered in what is now Badlands National Park. The jaw is in the collections of the Smithsonian Institution National Museum of Natural History in Washington, D.C.

Fossil Facts:

  • Titanotheres (or brontotheres) were large, herbivorous mammals.
  • They lived in open ares close to nearly-tropical forests in North America and Asia.
  • They went extinct at the end of the Eocene.
  • The first fossil scientifically described from the American West was a titanothere jaw.

    Go See Them!

    Titanothere fossil remains can be seen at our partner museums South Dakota School of Mines, Museum of the Rockies, and the Tate Museum. Their remains have been found at such NPS areas as Badlands, Florissant Fossil Beds, and John Day Fossil Beds. For more information on these partners, click on their links from our Partners tab.

    Word Origins:

  • Titanothere: titan refers to a Greek god, symbolic of brute force and large size. theros is Greek for "wild animal."
  • Brontothere: bronto is Greek for "thunder." theros is Greek for "wild animal."
  • Learn about more National Fossil Day artwork:

  • The NFD logo features a titanothere.
  • The 2011 artwork features a mosasaur and ammonites.
  • The 2012 artwork features a mammoth.
  • The 2013 artwork features Paleozoic marine invertebrates.
  • The 2014 artwork features Mesozoic ecosystems
  • The 2015 artwork features Cenozoic life and landscapes
  • The 2016 artwork features Pleistocene life and landscapes
  • Last updated: January 11, 2012