The titanotheres are extinct relatives of horses, rhinos, and tapirs. Some titanotheres became quite large; the titanothere Brontops, reconstructed at right by the painter Bruce Horsefall, was nearly as massive as an elephant.

The "horns" of the titanotheres make them resemble rhinos. However, they do not have horns, or even structures of stiffened hair, as in true rhinos, but instead have bony structures covered in thick skin.