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.