THE DESCENT OR ORIGIN OF MAN 113 



Archbishop Sumner formerly maintained" that man 

 alone is capable of progressive improvement. That he is 

 capable of incomparably greater and more rapid improve- 

 ment than is any other animal, admits of no dispute; and 

 this is mainly due to his power of speaking and handing 

 down his acquired knowledge. With animals, looking first 

 to the individual, every one who has had any experience ia 

 setting traps knows that young animals can be caught much 

 more easily than old ones ; and they can be much more 

 easily approached by an enemy. Even with respect to old 

 animals, it is impossible to catch many in the same place 

 and in the same kind of trap, or to destroy them by the 

 same kind of poison; yet it is improbable that all should 

 have partaken of the poison, and impossible that all 

 should have been caught in a trap. They must learn cau- 

 tion by seeing their brethren caught or poisoned. In North 

 America, where the fur-bearing animals have long been pur- 

 sued, they exhibit, according to the unanimous testimony 

 of all observers, an almost incredible amount of sagacity, 

 caution, and cunning; but trapping has been there so long 

 carried, on, that inheritance may possibly have come into 

 play. I have received several accounts that when telegraphs 

 are first set up in any district, many birds kill themselves 

 by flying against the wires, but that in the course of a very 

 few years they learn to avoid this danger, by seeing, as it 

 would appear, their comrades killed." 



If we look to successive generations, or to the race, there 

 is no doubt that birds and other animals gradually both ac- 

 quire and lose caution in relation to man or other enemies;" 

 and this caution is certainly in chief part an inherited habit 

 or instinct, but in part the result of individual experience. 



" Quoted by Sir C. Lyell, "Antiquity of Man," p. 497. 



'^ For additional evidence, with details, see M. Houzeau, "Les Faculty 

 Mentales," torn, ii., 1872, p. 147. 



^ See, with respect to birds on oceanic islands, my "Journal of Researches 

 during the Voyage of the Beagle," 1845, p. 398. "Origin of Species," Sth 

 edit., p. 260. 



