36 ETHICAL ASPECTS OF EVOLUTION 



burrows, instead of using holes ready made for them by other 

 animals. The suggested explanation is as follows : The 

 development of the protective coloration and habits probably 

 owes its origin to the short-eared owls and hawks which are 

 noticed to frequent the sandhills, and which would more 

 readily perceive and capture the darker mice. 1 



This, though put forward as a crucial instance, does 

 not appear to contain anything which bears out the theory 

 as stated by the author, that evolution is brought about 

 by the action of natural selection on variations, in selecting 

 some, and rejecting others . There was no evolution in 

 the sense in which Mr. Vernon uses the word ; no increase 

 of complexity, or of fitness to survive, and if the word 

 selection applied at all it was for destruction ; the animals 

 which did survive were wholly unaffected. The instance 

 will, however, repay a closer examination. 



It does not seem necessary to discuss the general bearings 

 of the new protective habit of burrowing holes ; our infor 

 mation on that point is insufficient. We are not told whether 

 the mice found in their new quarters holes ready made for 

 them by other animals. If they did, it is not clear why those 

 should not have had the same protective value as holes made 

 by themselves, especially as they were new to the work, 

 and the other animals may be presumed to have had long 

 practice. If they did not find them, then it is probable 

 that their inherited instinct to have recourse to holes would 

 have prompted them to make them, even if there had been 

 no hawks to escape from. 



The change of colour is more instructive, and suggests 

 the following observations. 



First. There was no struggle for existence between the 

 mice which survived and the mice which succumbed. The 

 island was roomy, and, for all we know, all the mice, whatever 

 their colour, might have survived and multiplied, side by 

 side, for an indefinite period at any rate, competition is 

 not said to have influenced the result. It was not a case 

 under the law of struggle for existence. 

 1 Loc. cit., p. 352. 



