AMERICAN MOUNTAIN SHEEP 
105 
sheep (Ovis nivicola) is more nearly akin to the American 
sheep than it is to other Asiatic ones, and the occurrence 
on both sides of Bering Strait of such near relations 
forms one of the strongest buttresses for the belief in 
a geologically recent land connection between Asia and 
North America in the neighbourhood of Bering Sea. The 
various forms of American sheep are entirely confined to the 
western mountain region, where they are found from the 
Alaska mountains to the mountains on the long peninsula 
of Lower California, and eastward as far as Yellowstone Park. 
The home of the big-hom is the loftiest rim-rock of the high 
mountain plateaux, or the most rugged and forbidding bad¬ 
lands of the middle altitudes. In summer, says Dr. Horna- 
day,* its favourite pastures are the treeless slopes above the 
timber-line, and in winter it paws through the snows of the 
mountain meadows to reach the tallest spears of grass. When 
the raging storms and deep snows of winter drive the elk and 
deer down into the villages for food and shelter, the mountain 
sheep makes no perceptible change in its habitat. Its agility 
is nothing short of marvellous, and, from its wariness and diffi¬ 
culty of approach, it is a favourite object of pursuit of the 
experienced hunter. 
If, as it seems likely, the American mountain sheep has 
entered North America from north-eastern Asia within recent 
geological times, the fact of its having spread to Lower Cali¬ 
fornia and developed several distinct forms is an argument 
in favour of a pre-Glacial immigration. That sheep had 
already penetrated to North America in Pliocene times is 
also proved by the discovery of the horn cores of a sheep 
(Ovis scaphoceras) in northern Nicaragua.f 
The comparatively dull-witted Rocky Mountain goat (Ore- 
amnos montanus) shares with the big-horn the almost inac¬ 
cessible peaks and ridges of the Rocky Mountains, but, being 
clumsy and slow, it rarely ventures far from its usual haunts. 
Unlike the sheep, the Rocky Mountain goat has a very local 
and discontinuous range.$ It seems almost as if its original 
home had been in the coast ranges of Oregon and Washington, 
* Hornaday, W. T., “ Notes on the Mountain Sheep,” p. 77. 
t Lucas, F. A., “ Fossil Bison of North America,” p. 756. 
f Grant, Madison, “The Rocky Mountain Goat,” p. 9. 
