The red panda is the only surviving descendant of an extinct genus of bears, Protursus. It belonged to the Ailuridae family and evolved from Ursavus elmensis 10 million years ago. Sometime between 5 to 6 million years ago, it branched off into Ursus minimus.

There are very few fossils of Protursus. A single molar tooth gave rise to the original description. A bear that was more advanced than Ursavus yet not as developed as Ursus.

The only known species of the genus is Protursus Simpsoni. This bear was the size of a large dog, with square molars, heavy limbs, and a short tail.

In 1976, Miquel Crusafont-Pair and Bjorn Kurtn assigned Protusus to the Ursidae family. And in 2005, Stephane Peigne moved it to the Ailuridae family.