Preying upon this great assemblage of hoofed animals was a corresponding array of Carnivora, most of which were indigenous and derived from American stocks, but there was a considerable migrant element also, such as the bears and badgers. Nearly all the modern kinds of flesh-eaters found in the North America of to-day were already here in the Pleistocene, minks, weasels, martens, skunks, otters, badgers, wolverenes, raccoons, foxes, wolves, coyotes, pumas, etc., etc., but there were several others which are either now extinct or no longer to be found in this continent. Of the extinct types much the most striking were the several species of †sabre-tooth tigers (_†Smilodon_, see Frontispiece) which have been found in the greater part of the United States and no doubt ranged over the whole. These were massive, short-tailed and rather short-legged, but very muscular and powerful, cat-like animals, in which the upper canine teeth were converted into great, recurved, scimitar-like tusks. These large beasts of prey, which about equalled the Leopard in height, but were far heavier, belonged to a group which, at one time or another, spread over nearly the whole world and persisted much later and attained a larger size and higher development in the western hemisphere than in the eastern. They had a very long American ancestry, from the lower Oligocene to the end of the Pleistocene, but the place of their origin is still unknown. In addition to the pumas and lynxes, there were some very large true felines (_Felis †atrox_ and _F. †imperialis_), which closely resembled the Lion (_F. leo_) in size, appearance and structure, and have been found in California and the Mississippi Valley; probably these great cats were immigrants, but they may represent a native development of Miocene and Pliocene stock; the history of the family is too imperfect for a decision of this question. Besides coyotes and wolves which are indistinguishable from existing species, there were some very large wolves, now extinct, of which the commonest and most widely distributed was _Canis †dirus_ (also called _C. †indianensis_) so abundant in the asphalts of southern California. Bears were not so common in the middle Pleistocene and have not been found in the older part of that epoch, though they probably had already reached North America from the Old World, where they originated. Their absence from the older Pleistocene (Equus Beds) may be accounted for by the fact that those beds contain a fauna of the open plains, while bears are chiefly forest-living animals. An extinct type of the family is the group of species which constitute the †short-faced bears (_†Arctotherium_), very large and powerful creatures, with remarkably shortened jaws, which have been found from ocean to ocean. The smaller beasts of prey, badgers, weasels, etc., were, as intimated above, substantially the same as now.