DOMESTIC ANIMALS 335 
living in Europe, Asia, or Northern Africa in the wild state, 
and in some cases still to be found in that condition. Gen- 
erally speaking, they were brought into captivity in prehistoric 
times, some thousands of years ago. Our domestic cattle 
were probably derived from at least three different species 
found wild in Europe in early times, as the bison, the elk, and 
the deer still occur in America at present. The horse was 
associated with man long before the beginning of historic 
times and its ancestry is largely a matter of speculation. But 
we recognize three very different families: the ponies of the 
Shetland Islands and other northern lands, the heavy horses 
found in the larger part of Europe in early historic times, and 
the lighter and swifter horses of Arabia and Northern Africa ; 
and it is possible that each of these families descended from a 
different species of which we have no knowledge in the wild 
state. The ancestry of our hogs is clearer. It is generally 
assumed that they originated from the wild boar of Europe, 
North Africa, and Asia Minor. Of sheep there are more than 
twenty wild species in different parts of the world, one of 
them being the well-known Rocky Mountain sheep or bighorn 
of our own country. But it is not known for certain whether 
our domestic breeds were derived from one of these species or 
from still another that is no longer found in the wild state. 
The origin of our various kinds of poultry is discussed in 
another place in this book. 
Of all the domestic animals, the New World has contrib- 
uted only our turkey and the llama of South America. The 
bison, elk, deer, antelope, prairie chicken, wild ducks and 
geese are readily domesticated, but their use has not yet 
attained to any great degree of practical importance. 
How Man Has Improved the Animals He Has Domesti- 
cated. — From the time when animals were first reared by 
