COLOURS AND COLORATION 37 



flakes if the hand be drawn along the back. The young 

 seals are quite uninjured by the sun, being protected, no 

 doubt, by the white colour of their coat." 



In discussing problems of coloration one runs the risk 

 of an unconscious bias towards one aspect only. We are 

 inclined to concentrate attention on the stripes and spots, 

 and their waxing and waning, and so lose sight of their 

 relation to the external world. This is a danger which 

 one must not allow to pass out of mind, for the two 

 aspects are mutually dependent on one another if we are 

 to arrive at a right understanding of the facts under 

 review. 



So far as the evidence goes in regard to mammals, it 

 would seem that such species as dwell amid cover afforded 

 by vegetation are striped, or spotted, those which dwell 

 out in the open are " self-coloured." But there are many 

 exceptions to such generalisations, and it must not be 

 forgotten that these patterns — forming as they do a 

 more or less perfect obliterative coloration, causing the 

 solid body to vanish, as it were, into thin air — are effective 

 only when the creatures so marked are at rest. But this 

 is when it is of greatest use. 



In many cases, by reason of the bulk of the animal, 

 or the development of efficient weapons of offence, a 

 patterned coat is of no importance as a means of pro- 

 tection, and accordingly gradually disappears. Yet it 

 maintains its purpose during the early stages of growth 

 before the weapons have developed ; and hence, as in 

 the case of the wild swine, the ancestral livery is revived 

 in the young. We may take it that so soon as these 

 patterns fail to serve any useful end — their purpose is 

 to " cut up " the solid appearance of the body, and so 



