Hell Pigs: Ancient Apex Predators of Prehistoric Earth : Weighing in at 2,000 pounds and sporting arm-sized fangs, the entelodont earned its status as the "hell pig" of prehistoric North America. Today, the entelodont live only in nightmares. The terrifying beasts went extinct between 19 and 16 million years ago. Originating in Mongolia in the middle Eocene epoch, these hell pigs spread to Europe and even to North America and existed for nearly 30 million years. Paleontologists have uncovered fossils from one of the largest breeds of entelodont, called Dinohyus or Daeodon, in Nebraska, with other fossils having been discovered in central states like South Dakota and Wyoming. It is believed the roaming hell pig likely enjoyed floodplains and woodlands. The fossils look just like the bones of an enormous dinosaur. The skeleton has huge teeth, a long snout, and deep-set eyes. In some cases, the head of the hell pig took up 35 to 45 percent of the creature’s total body mass and...