Miacis,genus of extinct carnivores found as fossils in deposits of early to late Eocene age the late Paleocene Epoch (65.5–55.8 million years ago) to the late Eocene Epoch (55.8–33.9 million years ago) in North America and of late Eocene age in Europe and Asia (the Eocene Epoch lasted from 57. 8 to 36.6 million years ago). Miacis is representative of a group of early carnivores, the miacids, that were the ancestors of the modern carnivores. Miacids retain primitive characteristics present in the creodonts, an older group of mammalian carnivores, such as low skulls, long, slender bodies, long tails, and short legs. Miacis retained the primitive number of teeth, 44, although some reductions in this number were apparently in progress; some of the teeth are reduced in sizemodern caniforms—which include the canids (that is, the dogs, coyotes, wolves, foxes, and jackals) and a large group made up of the bear, raccoon, and weasel families. Miacids were quite diverse, with body masses that ranged from about 1 to 7 kg (2.2 to 15.4 pounds). It is probable that the earliest members of the genus were at least partly arboreal (tree dwelling), capable of reversing their hind feet much as squirrels do when they climb. The hind limbs were longer than the forelimbs, and the pelvis was very doglike in form and structure. Some specialized traits are present in the vertebrae. Miacis and related forms had brains that were relatively larger than those of the more primitive creodonts; the increase in brain size as compared with body size probably reflects an increase in intelligence. Miacis was probably a forest dweller that preyed upon smaller animals; it was very weasel-like in formsome species were similar to civets in form, whereas others bore a resemblance to kinkajous.