| Named By: | Edward Drinker Cope in 1873 |
| Time Period: | early to middle Miocene 20.43-13.6 Ma |
| Location: | Across North America |
| Size: | About 1.2 meters long |
| Diet: | Carnivore |
| Fossil(s): | Multiple individuals |
| Classification: | | Chordata | Mammalia | Carnivora | Canidae | Borophaginae | |
| Also known as: | | Aelurodon francisi | Aelurodon simulans | |
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 other bear dogs like the giant mustelid genus of bone-crushing canidae, Cynarctoides. As the bear dogs and giant mustelids became extinct, Tomarctus further radiated to fill a line of dogs which filled the hyena-like fruit eating and bone-crushing niches.