Hyaenodon

## *Hyaenodon gigas*

> *Hyaenodon. Despite the name, these are not relatives of Hyenas. These are more dangerous by far.*
>
> Narrator, about *Hyaenodon*, Jaws like a Gillotine

***Hyaenodon*** (name meaning "*Hyaena Tooth")* is a genus of Hyaenodontidae that originated during the Late Eocene epoch in what is now North America, Europe, Asia, and Africa. Measuring 6 meters long, standing 2 meters tall and weighing 500 kilos, these fast and vicious canine-like rhinoceros-sized mammalian carnivores, despite the name, they were not at all related to Hyenas. Among the apex predators of their time, they hunted and killed in packs.

In the Series 2 episode "*Jaws like a Gillotine,*" a pack of *Hyaenodons,* consisting of six adults and five pups, were living from Oligocene Mongolia, 25 million years ago.

## Facts

### Era & Discovery

*Hyaenodon* first appeared in the Middle Eocene period, about 48 million years ago, and lived through to the Middle Miocene epoch, 15 million years ago. They were among the apex predators in their environment, often rivaled by the prehistoric hogs *Entelodon*.

*Hyaenodon* was first discovered in 1838. *Hyaenodon* translates into "*hyena tooth*" even though the animal is nowhere near related to any feliforms or any of the modern carnivores.

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. On the contrary, the two species *H. microdon* and *H. mustelinus* weighed 100 times less than *H. gigas*.

### Physical Attributes

A large, predatory, and territorial canine-like creature, *Hyaenodon* may seem smaller in appearance compared to larger creatures, such as a *Paraceratherium*. However, these carnivorous mammals were the size of modern rhinos, standing 5 – 6 feet (1.6 – 2 m) tall, measuring around 20 feet (6 m) long, weighing a total of 500 kg (1,000 lbs.), and were easily capable of killing a newborn *Paraceratherium* calf, assuming they could get passed the mothers. In addition to being deadly carnivores, they were also significantly fast and agile predators, able to quickly jump the length of a wide stairway to intercept fleeing prey. Their rivals in size were *Arctotherium* and *Andrewsarchus*.

*Hyaenodon* were not at all related to modern-day hyenas, despite their name. Nevertheless, they were even more dangerous. Typical of early carnivorous mammals, *Hyaenodon* has a massive skull, but only a small brain; it has a long skull with a narrow snout, its neck is shorter than its skull, while its body is long and robust and terminated in a long tail. With a powerful set of teeth, *Hyaenadon* had a bone-shattering bite force of over 1,300 lb psi and a design in the jaws that allowed the teeth to sharpen themselves throughout their entire life.

### Behavior & Traits

*Hyaenodon* was an apex predator, among the top predators of their environment. This animal preyed on the bizarre group of animals called *Chalicotherium*, newborn or juvenile *Paraceratherium*, bear-dogs and a large, omnivorous relative of swine, the *Entelodon*. Its sheer size and meat-shearing teeth would make a deadly combination, making it an efficient and successful predator. It would also hunt cooperatively with other members of its kind. However, like most other early carnivorous mammals, *Hyaenodon* wasn't the brightest of animals.

*Hyaenodon* were stalkers, preferring to spy on and stalk their prey from among cover and shadows, then abruptly leap in for the kill. *Hyaenodon* apparently lived in very close family units and had fierce parental instincts; mother *Hyaenodon* would follow and try to stay close to their pups wherever they went, ruthlessly attacking and killing any and all animals that could potentially threaten the young, while the father *Hyaenodon* would guard the family unit's current surrounding area.

## Gallery

A *Hyaenodon* pair are smelling the air for the scent of prey
## Trivia

* The sound effects for *Hyaenodon* are that of spotted hyena as well as grizzly bear, lion, tiger, wolf, leopard and cougar.
* It is coincidental that *Hyaenodon* has lived the same amount of time as hyenas, both being 21 million years ago.