Hyaenodons, despite their similar names, were not related to present day hyenas. They also weren’t particularly hyena-like in their appearance or behavior, which likely bore a closer resemblance to modern day wolves. Hyaenodons were widespread apex predators in their time, and the largest of these was Hyaenodon gigas.
The genus Hyaenodon contains a wide size range of individual species, with some barely larger than weasels. Others, like H. gigas, were quite large and could weight over a thousand pounds. Hyaenodons had large skulls, long snouts, short necks, and relatively long and slender bodies. Despite the fact that their name means “hyena tooth”, Hyaenodon teeth were mostly suited for shearing meat from bone, whereas a hyena’s teeth are designed for crushing bones.
Height – 5 ft. (1.4 meters) at the shoulder
Length – 10 ft. (3 meters)
Weight – 1100 lbs. (500 kg)
Hyaenodon gigas was the apex predator of its time, playing an important ecological role in controlling prey populations. Many species of Hyaenodon likely competed with each other as they shared the same range and basic ecological niche. It’s been shown that some species of Hyaenodon would even prey upon other carnivores, and not just large herbivores.
History of Discovery
Hyaenodons were extremely successful predators that were able to spread across most of the world, with examples in Asia, North America, Europe and Africa. They also managed to span over 25 million years, longer than almost any other mammalian group in the fossil record, from the Eocene epoch to the Miocene epoch. Hyaenodon gigas lived in the Oligocene in Mongolia. Around this time, Hyaenodons in North America and Europe were dying out, though they persisted in Africa and Asia for many more millions of years.
The Princeton Field Guide to Prehistoric Mammals, Donald R. Prothero, 2017.