Science, Tech, Math › Animals & Nature Amphicyon Share Flipboard Email Print Wally Gobetz/flickr Animals & Nature Dinosaurs Prehistoric Mammals Basics Paleontologists Carnivores Dinosaurs & Birds Herbivores Marine Reptiles Amphibians Birds Habitat Profiles Mammals Reptiles Insects Marine Life Forestry Evolution View More By Bob Strauss Science Writer B.S., Cornell University Bob Strauss is a science writer and the author of several books, including "The Big Book of What, How and Why" and "A Field Guide to the Dinosaurs of North America." our editorial process Bob Strauss Updated March 04, 2019 Name: Amphicyon (Greek for "ambiguous dog"); pronounced AM-fih-SIGH-on Habitat: Plains of the northern hemisphere Historical Epoch: Middle Oligocene-Early Miocene (30-20 million years ago) Size and Weight: Varies by species; up to six feet long and 400 pounds Diet: Omnivorous Distinguishing Characteristics: Large size; bear-like body About Amphicyon Despite its nickname, the "Bear Dog," Amphicyon was directly ancestral to neither bears nor dogs. This was the most prominent genus of the family of mammalian, vaguely canine-like carnivores that succeeded the larger "creodonts" (typified by Hyaenodon and Sarkastodon) but preceded the first true dogs. True to its nickname, Amphicyon looked like a small bear with the head of a dog, and it probably pursued a bear-like lifestyle as well, feeding opportunistically on meat, carrion, fish, fruit, and plants. The front legs of this prehistoric mammal were especially well-muscled, meaning it could probably stun prey senseless with a single well-aimed swipe of its paw. Befitting a mammal with such a lengthy provenance in the fossil record--about 10 million years, from the middle Oligocene to the early Miocene epochs--the genus Amphicyon embraced nine separate species. The two largest, the appropriately named A. major and A. giganteus, weighed up 400 pounds fully grown and roamed the expanse of Europe and the near east. In North America, Amphicyon was represented by A. galushai, A. frendens, and A. ingens, which were slightly smaller than their Eurasian cousins; various other species hailed from modern-day India and Pakistan, Africa, and the far east. (The European species of Amphicyon were identified in the early 19th century, but the first American species was only announced to the world in 2003.) Did Amphicyon hunt in packs, like modern wolves? Probably not; more likely this megafauna mammal stayed well out of the way of its pack-hunting competitors, contenting itself with (say) piles of rotting fruit or the carcass of a recently deceased Chalicotherium. (On the other hand, oversized grazing animals like Chalicotherium were themselves so slow that elderly, sick or juvenile herd members could easily be picked off by a solitary Amphicyon.) In fact, it's likely that the Bear Dog faded from the world scene 20 million years ago, at the end of its long reign, because it was displaced by better-adapted (i.e., faster, sleeker, and more lightly built) hunting animals.