Plithocyon ursinus Head detail

Plithocyon could be referred to as a "dog-bear"

Belonging to an extinct subfamily of the Ursidae called the Plithocyoninae, cursorial bear relatives that show specializations in a manner that leads away from other carnivorous families. These predators are found from north America, to Mongolia, and Europe. Their exact region of origin is unknown however.

These aberrant carnivores were the dominant cursorial predator in the upper Miocene and Pliocene epochs. Their presence on the great plains of north America seems to have overshadowed the true canid forms, such as wolves and coyotes, whose fossils eventually become more common at the end of the Pliocene when the dog-bears dwindled towards oblivion.

The genus pictured here, bear-sized Plithocyon ursinus, whose remains are known from New Mexico, Nebraska and California, is Characterized by a heavy spinal column, short massive limbs, stubby tail and five-toed spreading digits suggesting a semi-digitigrade stance. The jaws contained  heavy stout canine teeth and large bone-crushing molars. It is not known if Plithocyon was a solitary predator or if it hunted in small groups or packs.