GIRAFFES AND MUSK OXEN 



observer of nature) I have never once seen a bird 

 feeding upon butterflies in Africa. 



The coloration of certain animals in the Arctic 

 and sub-Arctic Regions is somewhat remarkable, as 

 at certain seasons it is conspicuously out of harmony 

 with its surroundings, and cannot therefore be pro- 

 tective. The musk ox retains it dark brown coat 

 the whole year round, although it lives almost con- 

 stantly amidst a snowy environment. Mr. Wallace 

 tells us that the reason why the musk ox does not 

 turn white is because it has no enemies to fear, and 

 therefore has no need of a protective coloration. 

 He says : " Then we have that thoroughly Arctic 

 animal the musk sheep, which is brown and con- 

 spicuous ; but this animal is gregarious, and its 

 safety depends on its association in small herds. 

 It is therefore of more importance for it to be able 

 to recognise its kind at a distance than to be con- 

 cealed from its enemies, against which it can well 

 protect itself so long as it keeps together in a com- 

 pact body." As, however, according to the experi- 

 ence of Arctic travellers, large numbers of young 

 musk oxen are annually killed by wolves, this ex- 

 planation of a case in which an animal is manifestly 

 not protectively coloured does not seem altogether 

 satisfactory. Mr. Wallace, it may be noted, calls 

 special attention to the coloration of the giraffe, 

 which he considers to be protective ; yet nothing, I 

 think, is more certain than that a far smaller 

 percentage of giraffes are killed annually by lions in 

 Africa than of musk oxen by wolves in Arctic 

 America. If this is so, the musk ox has more need 

 of protective coloration than the giraffe. The 

 musk ox is, I think, the only one' amongst the few 

 truly Arctic mammals which does not turn white 

 during the winter months, for, unlike the barren 

 ground caribou, it does not migrate southwards in 

 the autumn to the dark spruce forests, which change 



