The even-toed ungulates became quite successful. Numerous forms appeared, including a variety of pigs, deer, antelope, pronghorns, and giraffes. The elephants also diversified. Many developed long trunks and some had shovel-like lower tusks in addition to the upper tusks.

This detail of a Smithsonian mural by the great paleontogical artist Jay Matternes shows how hoofed ungulates flourished in the open grasslands of the Miocene. Two horse genera are depicted here: Pliohippus (tan with stripes) and Neohipparion (solid brown).