90 THE DESCENT OF MAN. 



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 in 

 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 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 

 acquire 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 expe- 

 rience. A good observer, Leroy,J states that in districts 

 where foxes are much hunted the young, on first leaving 

 their burrows, are incontestably much more wary than the 

 old ones in districts where they are not much disturbed. 



Our domestic dogs are descended from wolves and jackals, 

 and though they may not have gained in cunning, and may 



*For additional evidence, with details, see M. Houzeau, "Les 

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



f See, with respect to birds on oceanic islands, my. "Journal of 

 Researches during the voyage of the ' Beagle/ " 1845, p. 398. " Ori- 

 gin of Species," 5th edition, p. 260. 



{"Lettres Phil, sur I'lntelligence des Animaux," nouvelle edit,, 

 1892, p. 86. 



See the evidence on this head in chap, i, vol. i, " On the Varia- 

 tion of Animals and Plants under Domestication." 



