THE EVOLUTION OF INSTINCT 123 
him, even without the warning cry, and that the fear of a 
person in white or yellow would have continued all their 
lives.” 
Birds have been pursued by hawks for countless gener- 
ations, but there is, according to Lloyd Morgan, no evidence 
that they have an instinctive fear of hawks, any more than 
of large moving objects in general which are seen in the air. 
Such fear is readily taught the young, and different species of 
hawks, as Hudson has shown, come to inspire different 
degrees of fear according to their varied powers of harm. 
While instinctive fear of particular enemies may exist in 
certain animals, the evidence that it has in any case been 
recently acquired is entirely inadequate. There seems to 
be more evidence that wildness has been partially lost in 
the young of some domesticated animals. Darwin states 
that “hardly any animal is more difficult to tame than the 
young of the wild rabbit; scarcely any animal is tamer than 
the young of the domestic rabbit”; and also that the young 
of the tame duck are more tame than those of the wild duck 
a statement which is confirmed by the observations of 
Dr. Rae. The evidence that the diminution of wildness is 
due to the disuse of the instinct is not, however, sufficient. 
The differences may have been due, in part at least, to dif- 
ferences among the wild ancestry of the species, or they may 
have arisen through selection, perhaps unconsciously,during 
domestication. The wilder individuals would be more apt 
to escape or fare ill than the tamer ones, and there would 
therefore be a certain tendency for selection to diminish the 
wild instinct. It would require more careful study and 
comparison of the instincts of the young of domesticated 
and of wild species than has yet been made to-furnish ade- 
quate evidence for the loss of fear through disuse. 
We shall not enter, at any great length, into a discussion of 
