True cats of the genus Felis were in existence before the close of the Miocene, and yet earlier related forms are known.  Throughout the greater part of the Tertiary the remarkable type known as sabre-toothed cats were numerous and widely spread, and in South America they even lasted so far into the Pleistocene that it is probably true that they existed side by side with man.  Some of them were as large as any existing cat and had upper canines six inches or more in length.  Cats have no near relations upon the American continent, nor do they appear to have ever had many except the sabre-tooths.  Of present species some fifty are known, inhabiting all of the greater geographical areas except Australia.  They are tropical and heat loving, but the short-tailed lynxes are northern, while both the tiger and leopard in Asia, and puma in America, range into sub-arctic temperatures, and it is a curious anomaly that while Siberian tigers have gained the protection of a long, warm coat of hair, pumas from British America differ very little in this respect from those of warm regions.

No other cat has so extensive a range as Felis concolor and its close allies, variously known as puma, cougar and mountain lion, which extends from the Atlantic to the Pacific, and from latitude fifty-five or sixty north, to the extreme southern end of the continent.  As far as is known, it is a recent development, for no very similar remains appear previous to post-tertiary deposits.

Bears of the genus Ursus are of no great antiquity in a geological sense, for we have no knowledge of them earlier than the Pliocene of Europe, and even later in America, but fossils becoming gradually less bear-like and approximating toward the early type from which dogs also probably sprung, go back to the early Tertiary creodonts.

Cats, as we have seen, are chiefly tropical, while bears, with two exceptions, are northern, one species inhabiting the Chilian Andes, while the brown bear of Europe extends into North Africa as far as the Atlas Mountains.

The family Procyonidae contains the existing species which appear to be nearest of kin to bears.  These are all small and consist of the well-known raccoon, the coatis, the ring-tailed bassaris and the kinkajou, all differing from bears in varying details of tooth and other structures.  The curious little panda (Aelurus fulgens) from the Himalayas, is very suggestive of raccoons, and as forms belonging to this genus inhabited England in Pliocene times, it is possible that we have pointed out to us here the origin of this, at present, strictly American family; but, on the other hand, evidence is not wanting that they have always been native to the soil and came from a dog-like stock.

As we have already seen, bears have the same dental formula as dogs, but as they are less carnivorous, their grinders have flatter surfaces and the sectorials are less sharp; in fact they have very little of the true sectorial character.  It is unusual to find a full set of teeth in adult bears, as some of the premolars invariably drop out.