LOCAL AND SPECIFIC VARIETIES OF INSTINCT. 249 



authority of Dr. Andrew Smith, viz., " that in the uninhabited I 

 parts of South Africa the hygenas do not live in burrows,' 

 whilst in the inhabited and disturbed parts they do. Several 

 mammals and birds usually inhabit burrows made by other 

 species, but when such do not exist they excavate their own 

 habitations." 



In " Animal Intelligence " I stated, under the authority 

 of Dr. Newbury's Eeport on the Zoology of Oregon and 

 California, that the beavers in those districts exhibit the 

 peculiarity of never constructing dams, and seeing that the 

 building of these structures may be regarded as one of the 

 strongest instincts manifested by the species, I supposed 

 the failure of the Oregon and Californian beavers in mani- 

 festing this instinct to constitute a remarkable case of the 

 local variation of instinct. Professor Moseley, however, who 

 has travelled in Oregon, now writes me that this absence of 

 beaver dams is in his opinion due simply to tlie severity with 

 which the animals are trapped. "What few beavers that 

 remain are too constantly liable to interruption to be able to 

 construct dams, or for this to be worth their while. They thus 

 live a more or less vagrant life about the streams." It will be 

 observed, however, that Professor Moseley speaks of " the 

 few beavers that remain," whereas Dr. Newbury says of the 

 same districts : — " AVe found the beavers in numljers of which, 

 when applied to beavers, I had no conception." Therefore 

 I infer that since the time when Dr. Newbury's Pieport was 

 published, the number of the beavers must have been gi'eatly 

 reduced by trapping. But if so, at the time when the Eeport 

 was published, Professor Moseley's explanation of the absence 

 of dams can scarcely have applied to the facts of the case. 

 Hence, I am still disposed to think that we have in this case 

 an instance of the local variation of instinct — seeing that the 

 variation of habit was remarkable even before the introduc- 

 tion of the disturbing elements to which Professor Moseley 

 now alludes. Be this as it may, however, it is certain that 

 the solitary beavers of Europe present a striking local varia- 

 tion of instinct, not only in having lost their social habits, 

 but also in having ceased to build eitlier lodges or dams. 



The last instance of the local variation of instinct which 

 I have to adduce is one which has already attracted a good 

 deal of attention ; I refer to the barking of dogs.* The habit 



* A somewhat analogous instance seems to be supplied by the "cat-a- 



