ZOOLOGICAL POSITION AND STRUCTURE 43 



Mention has been already made of the fact that 

 sheep in the wild state are essentially mountain 

 animals whose headquarters are in Central Asia. 

 It has to be added that they shun forest, and feed 

 entirely by grazing, or by nibbling the shoots of 

 herbaceous plants, such as wormwood and heather. 

 This, of course, involves a life in the open, where, 

 in bright weather, they are exposed to the full sun- 

 light ; and to such an existence their type of colour- 

 ing is specially adapted. With the exception of the 

 all-white Alaskan bighorn, whose home is amid 

 snow and glaciers, all wild sheep have the upper 

 surface of the body much darker than the belly, 

 which is, in fact, white ; this arrangement of colour- 

 ing being designed to render the animals in which 

 it occurs as inconspicuous as possible when standing 

 in the open in full sunlight, owing to the fact that 

 the light belly neutralises the effect of the dark 

 shadow cast by the body. When the colour of 

 the upper-parts is fawn or rufous there is not 

 infrequently a black flank-band dividing the fawn 

 of the back from the white of the under surface, 

 and it is not unlikely that this may aid in breaking 

 up the outline of the animal when seen at a 

 distance. 



It is noteworthy that this protective type of 

 colouring disappears more or less completely in the 

 domesticated breeds, to which it would, of course, 

 be utterly useless. In a few instances, indeed, as 



