50 
THE DESCENT OF MAN. 
Part JL 
pursued, they exhibit, according to the unanimous tes- 
timony of all observers, an almost incredible amount 
of sagacity, caution, and cunning ; but trapping has 
been there so long carried on that inheritance may have 
come into play. 
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 ; 19 and this caution is certainly in chief 
part an inherited habit or instinct, but in part the result 
of individual experience. A good observer, Leroy , 20 
states that in districts where foxes are much hunted, 
the young when they first leave their burrows are in- 
contestably much more wary than the old ones in dis- 
tricts where they are not much disturbed. 
Our domestic dogs are descended from Avolves and 
jackals , 21 and though they may not have gained in 
cunning, and may have lost in waryness and suspicion, 
yet they have progressed in certain moral qualities, 
such as in affection, trust-worthiness, temper, and pro- 
bably in general intelligence. The common rat has 
conquered and beaten several other species through- 
out Europe, in parts of North America, New Zealand, 
and recently in Formosa, as well as on the mainland of 
China. Mr. Swinhoe , 22 who describes these latter cases, 
attributes the victory of the common rat over the large 
Mus coninga to its superior cunning; and this latter 
quality may be attributed to the habitual exercise of 
all its faculties in avoiding extirpation by man, as well 
19 4 Journal of Researches during the Voyage of the 44 Beagle,” 9 1845, 
p. 398. 4 Origin of Species,’ 5th edit. p. 260. 
20 ‘Lettres Phil, sur l’lntelligence des Animaux,’ nouvelle edit. 
1802, p. 86. 
21 See the evidence on this head in chap. i. vol. i. 4 On the Variation 
of Animals and Plants under Domestication.’ 
22 4 Proc. Zoolog. Soc.’ 1864, p. 186. 
