48 ANIMAL ARTISANS 



spontaneously that monotony of feature which agri- 

 culture produces elsewhere after generations of labour. 

 It was like some vast natural reclamation, made ready 

 for the flocks and herds of a continent. Yet to con- 

 sume this half-million square miles of food, instead of 

 legions of bison and wapiti-deer, as on the Northern 

 prairies, there were not enough native animals to crop 

 the grasses. South America has no wild oxen, or wild 

 sheep, or goats, or antelopes ; and on the pampas 

 and the Southern plains there was only one large 

 native ruminant animal, the pampas stag, with the 

 puma and jaguar, which have probably been attracted 

 south by the increase of imported animals which serve 

 them as food. 



Darwin's belief was that this scarcity of animal life 

 on these plains was also very recent, and that the 

 splitting up of the continents of North and South 

 America zoologically was effected by the rising of the 

 high Mexican plateau, beyond which few Northern 

 species wandered south. But since Darwin's day man 

 has filled in the blank left by Nature with a fauna 

 brought there across the ocean. These animals have 

 multiplied faster than ever did the bison herds, and 

 have changed, or are changing, the surface of the 

 steppe. 



Formerly the grey and misty levels of these plains 

 showed in winter but little life except the scattered 

 herds of wild horses, and the viscachas sitting by their 

 burrows. Now on these chosen pastures the hordes 

 of cattle blacken the plains. 



That modification of the herbage which Darwin 



