182 THE ORIGIN OF SPECIES 



Mr. Mivart then asks (and this is his second objection), if 

 natural selection be so potent, and if high browsing be so great an 

 advantage, why has not any other hoofed quadruped acquired a 

 long neck and lofty stature, besides the giraffe, and, in a lesser 

 degree, the camel, guanaco, and macrauchenia? Or, again, why 

 has not any member of the group acquired a long proboscis? With 

 respect to South Africa, which was formerly inhabited by numer- 

 ous herds of the giraffe, the answer is not difficult, and can best 

 be given by an illustration. In every meadow in England, in which 

 trees grow, we see the lower branches trimmed or planed to an 

 exact level by the browsing of the horses or cattle; and what ad- 

 vantage would it be, for instance, to sheep, if kept there, to ac- 

 quire slightly longer necks? In every district some one kind of 

 animal will almost certainly be able to browse higher than the 

 others; and it is almost equally certain that this one kind alone 

 could have its neck elongated for this purpose, through natural 

 selection and the effects of increased use. In South Africa the 

 competition for browsing on the higher branches of the acacias 

 and other trees must be between giraffe and giraffe, and not with 

 the other ungulate animals. 



Why, in other quarters of the world, various animals belonging 

 to this same order have not acquired either an elongated neck or 

 a proboscis, cannot be distinctly answered; but it is as unreason- 

 able to expect a distinct answer to such a question as why some 

 event in the history of mankind did not occur in one country while 

 it did in another. We are ignorant with respect to the conditions 

 which determine the numbers and range of each species, and we 

 cannot even conjecture what changes of structure would be 

 favorable to its increase in some new country. We can, however, 

 see in a general manner that various causes might have interfered 

 with the development of a long neck or proboscis. To reach the 

 foliage at a considerable height (without climbing, for which 

 hoofed animals are singularly ill-constructed) implies greatly in- 

 creased bulk of body; and we know that some areas support 

 singularly few large quadrupeds, for instance South America, 

 though it is so luxuriant, while South Africa abounds with them 

 to an unparalleled degree. Why this should be so, we do not 

 know; nor why the later tertiary periods should have been much 

 more favorable for their existence than the present time. What- 

 ever the causes may have been, we can see that certain districts 

 and times would have been much more favorable than others for 

 the development of so large a quadruped as the giraffe. 



In order that an animal should acquire some structure specially 



