AMEEICAN 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-horn 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. J 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. 

 t Grant, Madison, "The Eocky Mountain Goat," p. 9. 



