SOCIAL HEREDITY 281 



a species, many of its apparently ingrained and 

 fixed habits could be entirely changed in a single 

 generation. 



The case of a wild species of New Zealand parrot 

 which, although previously vegetarian, acquired after 

 the introduction of European sheep the habit of 

 feeding on the kidney fat of these animals, causing 

 the death of the sheep which it attacked, is often 

 quoted as an extraordinary example in nature of a 

 sudden change in the fundamental habit of life 

 in a wild species. But there can be no doubt that 

 sudden changes equally deep seated in the habits 

 of a whole species could be effected at will by obtain- 

 ing control of its social heredity. 



Many of the experiments gave the strongest in- 

 dications in this direction. There is no more 

 established vegetarian British bird than our common 

 wood pigeon. In one of my experiments with the 

 young of this species a young bird was brought 

 up with a carrion crow and a hawk which were 

 fed on raw meat. The young pigeon by example 

 was led to feed on the same food, and throve on 

 the exclusively meat diet. So fixed did the habit 

 thus acquired by social heredity become that when 

 the adult pigeon at a later stage was offered the 

 grains which formed the natural diet of its species 

 it did not recognize them as food. 



