1884.] on the Darwinian Theory of Instinct. 141 



distribution. It is easy to see the importance of such local variations 

 of instinct as evidence of the transmutation of instinct, if we reflect 

 that such a local variation is obviously on its way to becoming a new 

 instinct. For example, the beavers in California have ceased to make 

 dams, the hyasnas in South Africa have ceased to make burrows, and 

 there is a squirrel in the neighbourhood of Mount Airy which has 

 developed carnivorous tastes — running about the trees, not to search 

 for nuts, but to search for birds, the blood of which it sucks. In 

 Ohinitahi there is a mountain parrot which before the settlement of 

 the place was a honey-eater, but when sheep were introduced the birds 

 found that mutton was more palatable to them than honey, and 

 quickly abandoned their ancestral habits, exchanging their simple 

 tastes of honey-eaters for the savageness of tearers of flesh. For the 

 birds come in flocks, single out a sheep,' tear out the wool, and when the 

 sheep, exhausted by running about, falls upon its side, they bore into 

 its abdominal cavity to get at the fat which surrounds the kidneys. 



These, I think, are sufficient instances to show what I mean by 

 local variations of instinct. Turning now to the specific variations, 

 I think they constitute even stronger evidence of the transmutation 

 of instinct; for where we find an instinct peculiar to a species, or 

 not occurring in any other species of the genus, we have the strongest 

 possible evidence of that particular instinct having been specially 

 developed in that particular species. And this evidence is of parti- 

 cular cogency when, as sometimes happens, the change of instinct is 

 associated with structures pointing to the state of the instincts before 

 the change. Thus, for example, the dipper belongs to a non-aquatic 

 family of birds, but has developed the instinct, peculiar to its species, 

 of diving under water and running along the bottoms of streams. 

 The species, however, has not had time, since the acquisition of this 

 instinct, to develop any of the structures which in all aquatic families 

 of birds are correlated with their aquatic instincts, such as webbed 

 feet, &c. That is to say, the bird retains all its structural affinities, 

 while departing from the family type as regards its instincts. A 

 precisely converse case occurs in certain species of birds belonging to 

 families which are aquatic in their affinities, these species, however, 

 having lost their aquatic instincts. Such is the case, for example, 

 with the upland geese. These are true geese in all their affinities, 

 retaining the webbed feet, and all the structures suited to the display 

 of aquatic instincts ; yet they never visit the water. Similarly, there 

 are species of parrots and tree frogs, which, while still retaining the 

 structures adapted to climbing trees, have entirely lost their arboreal 

 habits. Now, short of actual historical or palseontological informa- 

 tion — which of course in the case of instincts is unattainable, seeing 

 that instincts, unlike structures, never occur in a fossil state — short, 

 I say, of actual historical or palaeontological information, we could 

 have no stronger testimony to the fact of transmutation of instincts 

 than is furnished by such cases, wherein a particular species while 

 departing from the instinctive habits of its nearest allies, still retains 

 the structures which are only suited to the instincts now obsolete. 



