Tomarctus is a canid genus of the extinct subfamily Borophaginae which inhabited most of North America during the late Early Miocene to the Early Barstovian age of the Middle Miocene (23—16 million years ago). Tomarctus existed for approximately 6.83 million years. This animal shared a period and ecology with a variety of bear dogs, giant mustelid genera, and the genus of bone-crushing Canidae, Cynarctoides. As the bear dogs and giant mustelids became extinct, Tomarctus were a hyena-like fruit-eating canidae.