3 i2 THE WILDERNESS OF THE UPPER YUKON 



though in regions and localities the rock colors vary 

 equally throughout their range in the north. 



Owing to the character of the country in which these 

 sheep live and to their habits, it is of the utmost impor- 

 tance to their enemies to detect them from a distance by 

 sight before making an attempt to capture them. The fol- 

 lowing observations are based upon the angle of vision 

 from which sheep are seen by man. The broken, moun- 

 tainous country which sheep inhabit, however, is such 

 that their enemies more often see them against a back- 

 ground of rock, slope, or ground surface (looking down 

 on them from above), rather than against a background 

 of cloud and sky. Hence for purposes of detection, these 

 observations apply for the most part to all the enemies 

 of sheep. For purposes of capture, they apply to all 

 enemies of sheep except the wolf; but even to the wolf, 

 they usually apply. 



If the pelage of white sheep were to remain immacu- 

 late, the animal would be conspicuous in summer any- 

 where above timber. But, except for a short time during 

 the month of November, the pelage is badly stained, and 

 this staining causes the white sheep to become quite 

 inconspicuous in some regions where the rock colors are 

 in harmony with it as in the Ogilvie Rockies, for ex- 

 ample. But in other regions, where the rock colors are 

 darker, the stained white sheep are so extremely con- 

 spicuous that on mountain-slopes they can be easily seen 

 two and three miles distant, and nearer than half a mile 

 they form a striking contrast to the background. This is 

 true among the mountains bordering the coast ranges in 



