LOCAL AND SPECIFIC VAEIETIES OF INSTINCT. 247 



ence to the local variation of instinct, I may here quote a 

 further statement from Captain Coues' work previously 

 cited; for it shows that even on different parts of the 

 American Continent the same species of birds exhibit these 

 differences in their mode of nest-building. He says : — " There 

 is no question of the fact that some of the Swallows which in 

 the East now invariably avail themselves of the accommo- 

 dation man furnishes, in the West live still in holes in 

 trees, rocks, or the ground ; " and he proceeds to give several 

 special instances.* Lastly, the fact has already been noted 

 that House-sparrows exhibit a similar local variation of 

 instinct wherever they come into contact with the dwellings 

 of man.t 



Passing on now to other animals, we find several instruc- 

 tive cases of the local variation of instinct among the Mam- 

 malia. Thus the curious habit has been observed among 

 cattle inhabiting certain districts of sucking bones. Arch- 

 bishop Whately made this the subject of a communication 

 to the Dublin Natural History Society many years ago. 

 Eecently it has been observed by Mr.. Donovan of cattle in 

 Natal,t and by Mr. Le Conte, of cattle in the United States. § 

 Probably this habit is induced by the absence of some con- 

 stituent of food in the grass which is supplied by the bones, 

 and therefore if the habit happened to prove beneficial to the 

 cattle (instead of deleterious as Whately asserts), it is easy 

 to see that cattle in a state of nature might become trans- 

 muted from herbivorous to omnivorous, or even purely car- 

 nivorous. Probably the ancestors of the Pig have passed 

 through the former of these stages. On the other hand, the 

 Bear seems to be in process of becoming omnivorous from 

 the contrary direction — being carnivorous in its affinities, but 

 not infrequently adopting the habit of eating grass and herbs. 



And in this connection I may refer to an interesting case 

 of transition from herbivorous to carnivorous habits which 

 was published at the Academy of Natural Science of Phila- 



* Op. cit., p. 394. This fact, T think, tends to confirm the statement of 

 Mr. Edward {Zool., p. 6842) that on the coast of Banffshire the house- 

 swallow presents a local instinct of building in caves and on projecting rocks. 



t When house-sparrows build in trees — which thej occasionally do and 

 which must be regarded as reversion to primitive instinct — "the structure is 

 very large, more than a yard in circumference, and covered with a dome." 

 ( YarreVs British Birds, 4th Ed., Pt. X, p. 90.) 



X Nature, vol, xx, p. 457. § Ihid. 



