Look down toward the river, and we may see an exception. That two-meter (six-foot) high “pig” walking away from the river, covered with mud, is heading right toward the _Moropus_. His name is _Dinohyus_ (“terrible pig”), and he’s just as short-tempered and stupid as _Moropus_. He looks like a giant peccary, but his size and over-large head give him away as an entelodont (“complete tooth”). These are pig-like animals, usually of large size, that aren’t related to the domestic pigs at all. _Dinohyus’_ skull is nearly one meter (three feet) long, and those tusks are as thick as a man’s wrist. Though we missed seeing him earlier, he must have been wallowing in the mud under the overhanging willows. Now he’s heading away from the river in search of lunch. He’s not very choosy about what he eats; it might be succulent leaves or fruits, or even the carcass of a dead animal. _Dinohyus_ is an omnivore, eating almost anything that has nourishment.
Right now it looks as though he’s on a collision course with the _Moropus_. He’s seen the larger animal, has stopped in his tracks, and is pawing the ground with his front feet. Up goes his head—and listen to that roar! He’s getting a good temper worked up. Off he goes at a full gallop, right toward the _Moropus_. It’s hard to believe that an animal as big as that pig could charge so fast. And look at the _Moropus_! He’s finally realized in his dim way that he’s about to be attacked. Up he goes on his hind legs, holding his front legs out ready for a downward blow with all eight claws. But suddenly _Dinohyus_ shifts his course just slightly, lets out another loud bellow as he avoids the _Moropus_, and thunders off toward the open prairie.
_Dinohyus_ has a smaller relative around here somewhere, a little fellow just over one meter (three feet) high, called _Entelodon_. His head is long and low and has flaring cheekbones and bumps along the underside of the jaw like his larger cousin’s. Another pig that lives along the Niobrara is _Desmathyus_ (“bond [filling a gap] pig”), a true North American pig or peccary. Its appearance probably wouldn’t surprise anyone; it looks very much like the peccaries that live in the American Southwest today. Its distant cousin, the domestic pig, was domesticated in the Old World from a European species of wild hog, and it was spread throughout the world by European colonists. In America, peccary evolution has run a long and conservative path. This group has changed relatively little in the 35 million years since it first appeared in the Late Eocene.