I ALASKA AND THE YUKON TERRITORY ii 



has been at least as potent a factor in bringing 

 about the white coloration of these animals in 

 winter as the necessity for protective coloration. 

 At any rate, in Alaska and the Yukon Territory of 

 Canada, where the country is covered with snow for 

 more than half the year, and where the hares are 

 white throughout the long winter, the foxes are 

 red, black, or a mixture of these two colours, all 

 the year round, and the lynxes grey ; yet these two 

 species of carnivorous animals depend almost 

 entirely on the hares for their food supply. It is 

 somewhat remarkable that in the sub-Arctic forests 

 of Alaska and the Yukon Territory, where the cold 

 is intense and the ground covered with snow for so 

 many months of every year, only the hares and the 

 stoats amongst mammals turn white in winter. But 

 in these countries the land is covered for the most 

 part with dark spruce forests, the influence of which 

 — if there is anything in the influence of environ- 

 ment — may have been greater in determining the 

 coloration of the mammals of this district than that 

 of the snow-covered ground. 



During winter in the Yukon Territory, moose turn 

 very dark in colour on the under parts of the body, 

 and at this season of the year leave the thick forests 

 and live in the comparatively open valleys amongst 

 willow and birch scrub, where they are said to stand 

 out like haystacks amidst their snowy surroundings. 

 The local race of caribou i^Rangifer osborni), which 

 live all the year round on the treeless mountain 

 plateaus, are very dark in colour (with the exception 

 of their necks), and, as I myself can testify, stand out 

 very plainly when the open ground they frequent 

 is covered with snow. Of the various races of wild 

 sheep inhabiting the mountains of Alaska, the 

 Yukon Territory, and Northern British Columbia, 

 some are white all the year round, and therefore 

 very conspicuous in summer when there is no snow 



