The group is believed to be derived from a creodont allied to the Eocene Palaeonictis (see creodonta).
The well-known plantigrade tread of bears is a primitive characteristic which has survived from their creodont ancestry.
There are, however, other points of likeness which seem rather to point to a creodont origin.
Any of various extinct carnivorous mammals of the order Creodonta of the Paleocene to the Pliocene Epochs. Creodonts had long, low skulls with crests to which chewing muscles were attached. They were the dominant carnivorous mammals for millions of years, and were once believed to be ancestral to modern carnivores.