THE LIFE OF MAMMALS 
branch dividing and subdividing into smaller and smaller branches, until 
the modern condition is attained.” 
It is plain, then, that to understand the history of the modern 
mammals we must learn something of the Creodonta. Professor 
E. D. Cope tells us that in the overflowing mam- 
malian fauna of the early Tertiary there was nothing 
which could be classed with the Carnivora of the present, which 
order did not appear before the Oligocene period. All the 
predatory beasts of that time differed from the Carnivora in 
various points of structure. Their brains were dispropor- 
tionately small and but little convoluted, indicating low intelli- 
gence. Their limbs were shorter, and the wrist and ankle 
joints less compact and strong; the feet less perfectly adapted 
to chasing and seizing; five-toed as a rule, and resting the heel 
upon the ground; and the tail was long and muscular. The 
teeth in most cases were of that small and primitive type still 
seen in the mouths of the Insectivora, adapted to feeding on 
insects and miscellaneous small things, both animal and vege- 
table. The smaller and more primitive creodonts, indeed, 
are almost indistinguishable from the contemporary insectivores. 
In their later and more advanced races we find certain teeth 
becoming more and more specialized for a flesh diet, but in 
only one family, the Miacidz, are these specialized teeth (car- 
nassials) the same ones as in the modern Carnivora. This 
likeness, with others, shows that our Carnivora are descended 
from the Miacide. The remaining families of creodonts could 
not compete with the miacids, because of their inferior equip- 
ment, and have left no descendants. 
The creodonts must have been big-headed, savage-looking 
animals, with jaws and teeth disproportionately large and long: 
short-legged, and long-tailed, resembling nothing in our world 
so much as the Tasmanian wolf and Tasmanian devil of Aus- 
tralia, to which, however, they were only remotely akin. Some 
were terrestrial, others dwelt and hunted on trees or in the 
80 
Creodonts. 
