Tomarctus ("cutting bear") is an extinct genus of canine which inhabited most of North America during the Early Miocene to Middle Miocene 23 Mya to 16 Mya. Tomarctus is derived from the Nothocyon and gave rise to Borophaginae, a short-face, heavy-jawed canine usually massive in size. Tomarctus shared its period of time with a variety of bear dogs like the giant mustelid genus of bone-crushing canidae. As the bear dogs and giant mustelids became extinct, Tomarctus further radiated to fill a line… (More on Tomarctus)