Entelodonts, known colloquially as “Hell Pigs,” “Killer Pigs,” or “Terminator Pigs,” were gigantic, fearsome omnivores known for their massive heads and impressive jaw strength. For 21 million terrifying years, these beasts crushed bones and ran through forests and floodplains all across North America, Asia, and Europe. Entelodonts walked among the other giant prehistoric animals of the Cenozoic Era until they went extinct more than 16 million years ago.
But Hell Pigs were not particularly vicious – nor, for that matter, were they actually pigs. Though they had piglike features, entelodonts were more closely related to other ungulates like hippos and whales. And they weren’t so much natural predators as they were opportunistic eaters who simply happened to be extremely large and powerful.
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Entelodonts Were Known For Their Bone-Crushing Teeth And Jaws
One telling relic of the entelodonts is a “pile of bitten-in-half camels” from the early Oligocene epoch. Renowned for their bite force, entelodonts possessed immense jaw strength and all four types of mammalian teeth. It is widely believed they were easily capable of crushing bone.
There were very few things the entelodonts couldn’t eat, thanks in large part to bony attachments on the skull and mandible.
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They Could Weigh Up To 2,000 Pounds
While sizes varied wildly between different genera, the overwhelming majority of entelodonts were substantially larger than any modern-day pig. The smallest grew to about 330 pounds, while the largest could weigh as much as 2,000.
The head took up a disproportionate amount of the animal’s total weight.
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They Had Extremely Large Skulls
The head of the largest type of entelodont, Daeodon, accounted for 35-45% of the beast’s full body length. When compared with Daedon’s comically scrawny legs, the massive entelodont’s head seems structurally impossible. However, bone structure and musculature helped distribute the weight of the head.
A solid sternum and tight rib cage coupled with huge, burly muscles not only supported the skull, but also provided a surprising amount of mobility and field of vision.
Photo: James St. John / Flickr / CC BY 2.0
They Had Distinct Bumps And Flanges On Their Heads
One of the entelodont’s most distinctive features was a collection of protruding bumps, ridges, and flanges on its face. The bumps were tusk-like in profile, and they served a number of purposes. The placement of the flanges helped protect their noses and eyes during fights, and may have even served as an offensive tool in their own right.
They also helped support the entelodonts’ powerful jaw muscles, perhaps contributing to their overwhelming strength.
Photo: Jay Matternes / Wikimedia Commons / Public Domain
Scientists Believe They Were Omnivores And Scavengers
Evidence suggests the entelodonts were omnivorous creatures, though the jury is still out on how often they caught and ate their own live prey. They had the pointed incisors and serrated canines of meat eaters; however, their jaw musculature and the wear on their molars suggests they ate plants, as well.
Due to their powerful jaw strength, they were capable of eating tough and hard foods. Much like the eating habits of modern pigs, the mixed diet of the entelodonts reflects a willingness to consume whatever was available.
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Their Legs And Necks Were Slender In Proportion To Their Heads
While their heads were tremendous in size, entelodonts had slender necks and tiny legs. Their thin necks were supported by compact, powerful muscles. As a species, entelodonts were cursorial, which means their limbs were adapted for running short distances. The radius and ulna, as well as the tibia and fibula, were fused together.
Despite their strange proportions, the entelodonts’ weight distribution optimized their ability to throw their massive bodies around while running very quickly.
Photo: Jay Matternes / Wikimedia Commons / Public Domain
Entelodonts Fought Each Other
There is a great deal of evidence to support the conclusion that entelodonts often fought one another. The tusk-like flanges and bumps on the sides of their faces were likely meant to protect the animals from the chomps and jabs of rival entelodonts.
These fights may have taken place as a method of asserting dominance, or possibly to take food from another member of the group. Due to the entelodonts’ preternatural ability to close their mouths around the heads of other animals, there’s no reason to believe they wouldn’t do so whenever possible.
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Despite Their Giant Heads, They Had Brains The Size Of An Orange
Entelodonts relied on strength and speed to ambush their prey, as they did not possess the wiles to play the long game of trapping and stalking their dinner. It didn’t hurt that many of their favorite targets – horses, camels, and rhinos – were quite unintelligent as well.
Dim wit was a major factor in the extinction of the enteledont family. The rise of fast and intelligent “bear dogs,” such as Amphicyon, created unfavorable competition for the enteledonts.
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Archaeotherium Was The First Of The Entelodonts
Archaeotherium and Daeodon are the two genera of entelodont that have been studied the closest. Archaeotherium, which means “ancient beast,” existed from the middle Eocene epoch to the late Oligocene epoch. While its territory extended across Asia and Europe, it was a dominant species in North America.
Approximately the size of a cow, Archaeotherium possessed a shallow skull, a powerful sense of smell, front-facing eyes, and jaws that could open very wide. Due to its small size in comparison to other entelodonts, the Archaeotherium was faster than its later relatives.
Photo: James St. John / Wikimedia Commons / CC BY 2.0
Daeodon Was The Largest Of The Entelodonts
Daeodon, also known as Dinohyus (“terrible pig”), was a massive, hulking creature that could grow to nearly two meters in height and more than four meters in length. It lived between the middle Oligocene and the early Miocene, and it was the last surviving genus of entelodont.
While its cheek flanges were small and blunt in comparison to that of Archaeotherium, Daeodon made up for it with its punishing bite force, which could easily crush bone. It would often use its sheer mass to intimidate or scare off other predators, which often included fellow Daeodon
Photo: Charles R. Knight / Wikimedia Commons / Public Domain
Though They’re Known As ‘Hell Pigs,’ Entelodonts Are Actually Related To Hippos And Whales
While they bear a strong resemblance to large pigs such as warthogs, entelodonts are more closely related to hippos and whales. Whales are the only remaining ungulates who prey on other animals, while hippos are scavengers. Though they were strictly terrestrial mammals, entelodonts were predators as well as scavengers, just like their descendants.
However, the reason for their undeniably pig-like attributes is not superficial. Entelodonts are an example of convergent evolution, a process through which largely unrelated animals develop similar features and tendencies due to similar environments and survival needs. As the habitat of the entelodonts more closely resembles that of a wild pig than the aquatic/amphibious environment of a whale or hippo, the name “hell pig” is still descriptively appropriate.
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They Likely Went Extinct Because Of Climate Change
Entelodonts went extinct between 16 and 19 million years ago, during the early Miocene. While numerous factors contributed to the entelodonts’ demise, climate change had the most immediately catastrophic effect. As global cooling began to take effect, the forests began to shrink and the vegetative plants favored by the entelodonts disappeared with them.
As the forests turned to grasslands, a new group of large ruminants emerged. These grass-eating herbivores were the ancestors of modern-day cows, sheep, horses, and goats. While the ruminants adapted to the new environment and diet, the entelodonts could not.
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Entelodont Fossils Have Been Found In South Dakota, Oregon, And Nebraska
Western North America is awash with entelodont fossils, as well as evidence of the creature’s hunting patterns. Many fossils of prey mammals featuring Archaeotherium bite marks have been found in Badlands National Park in South Dakota.
Archaeotherium was first discovered in the John Day Fossil Beds in Oregon, and a full-body skeleton of the Daeodon was found in what is now the Agate Fossil Beds National Monument in Nebraska.