Entelodon (Ent-tell-oh-don), meaning "Perfect-Toothed", was a large ancestor of hoofed animals (mainly pigs). It could grow up to two meters tall, about the size of a rhino, and weighed up to one tonne. Entelodon has been described as the 'pig from hell'. They were aggressive, and could easily fight off many predators.
Entelodon was like a moving waste disposal unit, capable of eating anything from rotten fruit, to dead bodies. Its strong jaws could crush bones, but it may have resulted in broken teeth. Its teeth also have wear marks, resulting from eating nuts, and roots. Strong muscles made it a fast runner, making it a hunter of small, hoofed animals. Its strong neck muscles could crush even the most solid of bones to a pulp. When food was scarce, they would even turn cannibalistic, eating each other.
Entelodons were very aggressive towards each other. Males, being solitary, they fought fiercely with each other over territory, and food. Many fossilized skulls have been found with deep wounds on the snout, showing that many fights resulted in terrible wounds. In fact, the only threat to an Entelodon was another one. Females were found in small family units, protecting their young from predators and male Entelodons.
Entelodon belongs in a group of Artiodactyl (even-toed, hoofed) animals called 'Entelodonts'. The group consists of large, brutish-looking cousins of pigs (though a group of scientists, including Spalding, believe that they're closer to whales and hippos instead). The group filled the niches of hunters and scavengers. Despite their initial success, the whole group became extinct twenty three million years ago due to competition with other predators, such as Amphicyon and the other bear-dogs. The appearance of true pigs and a climate change may've contributed to the Enteldonts extinction as well.