Hyaenodon translates into "hyena tooth" even though the animal is nowhere near related to any feliforms, or any of the modern carnivores. However, they were more dangerous. One of the features that differentiate Hyaenodon from hyenas is size. The genus Hyaenodon has several species all ranging in size. The largest species, H. gigas, is one of the largest terrestrial mammalian carnivores ever discovered. This species measured 5.5 meters (18 ft) in length and weighed a total of 500 kg (1,100 lb). On the contrary, the two species H. microdon and H. mustelinus weighed 100 times less than H. gigas, the species in the show.
Hyaenodon was an apex predator. This animal preyed on the bizarre group of animals called chalicotheres, newborn or juvenile indricotheres, bear-dogs and a large, omnivorous relative of pigs and wild boars, the Entelodonts. Its sheer size and meat-shearing teeth would make a deadly combination, making it an efficient and successful predator. However, like most other early carnivorous mammals, Hyaenodon wasn't the brightest of animals.
Next to large creatures such as an indricothere, Hyaenadon may have looked small, but they were as big as rhinos, and were easily capable of killing an indricothere calf, if they could get pass the mothers. Hyaenadon have a bone-shattering force of over 1,000 pounds per square inch.
A pair of Hyaenodon were seen watching a mother Indricotherium in labour giving birth to a male calf. The pair confronted and continuously attacked the mother and her calf but were unable to reach the calf in between its mothers legs. It is revealed that in the morning the mother and calf did indeed survive the Hyaenodon attack.
A Hyaenodon is seen stalking a herd of Chalicotherium. It successfully attacks and kills one by biting its neck. Before the animal could eat, a trio of Entelodonts appeared and challenged the Hyaenodon over the carcass. In a futile attempt to hide the scent of the carcass, the Hyaenodon defecated on it but it was worthless. The Hyaenodon was overpowered and was chased away by the Entelodonts.
A Hyaenodon being harassed by a trio of Entelodont. (Land of Giants)
During a downpour, a Hyaenodon is seen chasing an Entelodont but slips.
