Simocyon

The relationship of Simocyon to other carnivores has been controversial, but studies of the structure of its ear, teeth, and ankle now indicate that its closest living relative is the red panda, Ailurus, although it is different enough to be classified in a separate subfamily (Simocyoninae) along with related genera Alopecocyon and Actiocyon.

The species Simocyon diaphorus was described in 1832.

While the red panda is primarily herbivorous, the teeth and skull of Simocyon indicate that it was carnivorous, and it may have engaged in some bone-crushing, like living hyenas. The skeleton of Simocyon indicates that, like the red panda, it could climb trees, although it probably also spent considerable time on the ground. Simocyon and Ailurus both have a radial sesamoid, an unusual bone in the wrist that acts as a false thumb. Because Simocyon is considered carnivorous, the presence of a false thumb suggests that this structure likely evolved for climbing rather than for bamboo grasping and feeding. Its competitors during its time period were ailuropodine and tremarctine bears, nimravid false cats, and early canids and felids.