220 THE HAUNTS OF LIFE 
suit of grey and brown, puts on a white plum- 
age when the winter sets in; and the chestnut- 
brown stoat becomes the white ermine—snow- 
white all over save the black tip of the tail. 
Now this white dress gives its possessor a gar- 
ment of invisibility against a background of 
snow, enabling it to slink upon its victims and 
to elude its enemies. But there is something 
more—perhaps more important. For a warm- 
blooded animal in very cold surroundings the 
dress that loses least of the precious “ animal 
heat” of the body—the heat that makes it 
easier for the chemical process of the body 
to go on—is a white dress. 
We must not follow this subject further, but 
it is interesting to think out some of the other 
ways in which land animals meet the difficul- 
ties of the winter. What are the expedients 
adopted by moles, by harvest-mice, by the 
mountain hare, by squirrels, by the curlews 
on the moor, by the slow-worms, by the frogs? 
BETWIXT-AND-BETWEEN ANIMALS 
Of great interest are the betwixt-and-between 
animals, at present making the transition be- 
tween water and dry land. On many tropical 
