Hyaenodon: Paleogene Predator

Hyaenodon was a genus of large predatory mammal that appeared on Earth in the late Eocene through the Oligocene Epoch. Despite the name, hyaenodon was not related to modern-day hyenas, but rather belonged to a group of now extinct carnivores called creodonts. It was a very large mammal, the biggest of which stood 1.5 meters (4.9 feet) high at the shoulder, was ten feet long from nose to the tip of the tail, and weighed up to 1100 pounds. The smallest species were much smaller than this, standing only a foot tall at the shoulder. Fossilized remains of hyaenodon have been found on the continents of Asia, North America, Europe, and Africa, thus revealing a very wide range and high rate of success in the Cenozoic. The most common finds have been in Mongolia and regions of North America.

Like many other Paleogene mammal hunters, hyaenodon had a very large head capable of delivering a powerful bite. It is believed that this predator latched on to its prey's neck and used the crushing force of its jaws to suffocate the victim. Fossilized skull remains also reveal that hyaenodon probably had a keen sense of smell in order to locate prey. Despite the size of the skull, the brain cavity of this animal was quite small for its body mass. The majority of the skull size must have been used to anchor powerful tendons to open and close the enormous jaws, leaving very little room for much intelligence in the hyaenodon.

The larger species of this genus were unlikely to have hunted in groups due to their metabolic requirements and need for large amounts of food to maintain their great size. However, the smaller species could well have been pack hunters, using numbers to intimidate and bring down larger prey or swift herd animals. Also, because of their size, it is likely that they were unsuited to live in the forests and instead inhabited the Paleogene scrub plains of Asia and North America, hunting big game. It is likely that hyaenodons were opportunistic carnivores, meaning that they would eat whatever meat was available to them, whether fresh meat or carrion. Given the powerful, doglike build of these animals, it is likely that at least some species were definite predators.

Eventually the hyaenodons and all creodonts for that matter fell victim to competition from more modern predators such as dogs and big cats. Unable to preserve their status at the top of the food chain, hyaenodons went extinct by the end of the Pliocene Epoch.