Name Meaning: Hyaena tooth

Geologic Era: Oligocene

Location Found: Pennington County, South Dakota

Size: 40-60 kg, up to 3 meters long (for longest species…our specimen was considerably smaller)

Estimated Range: North America, Europe, Asia, Africa

Extinction: Early Miocene

This is a jaw fragment from a species of Hyaenodon, probably one of the mid to smaller ones. A likely candidate is Hyaenodon horridus. The teeth are still rather sharp, if small. This fragment came from the middle to back of the lower left jaw. Hyaenodon would have been a generalist predator, eating whatever it could catch and kill.

A variety of animals from the same time show damage that corresponds to Hyaenodon teeth. Based on this evidence, it seems that Hyaenodon aimed for the skull, and used its powerful jaw muscles to penetrate the skull of a prey item. This attack style is similar to modern big cats, many of whom are ambush predators. On the menu would have been early camels, oreodonts, and horses. A Dinictis skull (false saber tooth cat) shows puncture wounds that match the tooth pattern of Hyaenodon, showing that Hyaenodon was not above going after other predators. It is uncertain if this was active predation, or possibly the result of one animal trying to steal a kill from another.

Hyaenodon and its relatives, the creodonts, have no living descendants, though they are distantly related to modern mammals. Climate change was probably their undoing, as cooling global temperatures in the Miocene led to the shrinking of forests and the increase of grasslands. Many of the animals that Hyaenodon depended on for food disappeared, particularly the oreodonts. The final straw was the introduction of amphycyonids (beardogs) from Asia, which finally outcompeted Hyaenodon and its kin.

Image Credits:

Full Skeleton: By Daderot – Own work, CC0, https://commons.wikimedia.org/w/index.php?curid=17853648

Life Restoration: By Nobu Tamura email:nobu.tamura@yahoo.com http://spinops.blogspot.com/ – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=56197420