THE LIFE OF MAMMALS 
cyon), which was more dog than civet, plus bearlike features; and later 
we find Hyznarctos still more ursine, so that these represent a line of change 
from bearlike dogs into doglike bears, and connect the Amphicyon stock 
with the true bears and raccoons. Ina similar way fossil forms of the Upper 
Eocene and Lower Miocene connect the civet stock with the apparent 
ancestors of the fur-bearers (weasels, badgers, otters, etc.). It is not, 
indeed, until the late Miocene, near the end of the Tertiary period, that the 
groups of Carnivora as we now see them became distinctly set apart from 
one another by the dying out of the old intermediate stock forms. 
Saber-Tooths and Other Ancient Cats 
The cats, although not the oldest, stand as the most per- 
fected or specialized of all the kinds of carnivores, and probably 
of all kinds of animals, not excepting man. This splendid and 
very compact series first definitely appears in the Oligocene 
era, from an unknown ancestor among the creodonts. Some- 
where in its early history arose a divergent branch, starting in 
the Oligocene with such forms as Pseudozlurus and Archelurus, 
which developed amazingly throughout most of the Tertiary 
period, and to which Cuvier gave the name of ‘‘saber-tooth 
cats.” They were especially numerous and powerful in the 
Americas, yet abounded throughout the Old World. From 
the first these beasts showed a tendency toward enlarging the 
upper canines, until finally in such genera as Smilodon, as re- 
stored by Wolf, they became huge tusks. Dr. W. D. Matthew, 
who has made a particular study of these creatures, has given 
me the benefit of his conclusions in the ensuing account: — 
“Our prehistoric ancestors could have told us of an animal 
much larger and more powerful than any lions or tigers known 
to us, — the great saber-toothed tiger Smilodon, — 
which seems to have realized very completely the 
idea of the King of Beasts as portrayed in medieval tradition. 
This great carnivore equaled the largest polar or Kadiak bear 
in size. It was related to the large cats, but distinguished by 
its enormous upper canine teeth, enlarged into curving, sharp- 
86 
Smilodon. 
