336 A BOOK-LOVER'S HOLIDAYS 



the caribou had galloped, and walked behind 

 it when it became too tired to run, and then 

 galloped again when under the terror of his 

 approach the hunted thing once more flailed 

 its fading strength into flight. Its strength 

 was utterly gone when its grim follower at last 

 sprang on it and tore out its life. 



An arctic explorer once told me that on a part 

 of the eastern coast of Greenland he found on 

 one visit plenty of caribou and arctic foxes. 

 A few years later he returned. Musk-oxen 

 had just come into the district, and wolves fol- 

 lowed them. The musk-ox is helpless in the 

 presence of human hunters, much more help- 

 less than caribou, and can exist only in the ap- 

 palling solitudes where even arctic man can- 

 not live; but against wolves, its only other foes, 

 its habits of gregarious and truculent self-de- 

 fense enable it to hold its own as the caribou 

 cannot. The wolves which were hangers-on 

 of the musk-ox herds speedily killed or drove 

 out both the foxes and the caribou on this 

 stretch of Greenland coast, and as a result two 

 once plentiful species were completely replaced 

 by two other species, which change also doubt- 

 less resulted in other changes in the smaller 

 wild life. 



Here we can explain the reason for the change 



