CHAPTER FIFTY-SEVEN 



LIFE IN THE ARCTIC AND ANTARCTIC REGIONS 1 



I. THE frozen north, and the still more frozen south, The struggle 



with the en- 

 vironment 



are in most respects ill-suited for the development of 



terrestrial life ; yet they are of special interest to the 

 biologist. In the moist tropics, where life is most 

 abundant, it is its own chief enemy. Plant struggles 

 with plant, animal with animal, animal and plant 

 together. In the arctic, as in the desert, the principal 

 struggle is with the environment. There is generally 

 room enough, but how to endure the climate, to sur- 

 vive under such hard conditions, is the real problem. 

 Nature, however, makes the most of every opening, and 

 develops types which are so well adapted to seemingly Adaptation 

 adverse conditions that they cannot get along without *egk>ns 

 them. Thus the polar bear, accustomed to a world of 

 ice, looks hot and miserable in the London Zoological 

 Gardens, during the very temperate English summer. 



2. The north polar regions are radically different Life in the 

 from the south, in that the north pole is covered by a 

 frozen sea, whereas the south is in the middle of a great 

 area of elevated land. We might at first imagine that 

 land would be more favorable to animal life than sea, 

 but this is not the case. The sea, even in the extreme 

 north and south, is full of animal life, - - whales, 

 fishes, and invertebrates. The fishes may feed on 

 minute Crustacea or worms, the seals on fishes, the 

 polar bears on seals. Aquatic plants, mostly of 

 minute size, serve as food for the smaller animals. 

 Thus the sea is a source of food for so-called terrestrial 

 animals, which may live mainly upon the ice. In 



'The word "arctic" comes from arctos, Greek for "bear." Hence the 

 careless spelling "artic," a prevalent vice of students and others, is es- 

 pecially to be condemned. 



467 



