96 INSTINCT 



fishes and spiders; and in some centipedes the males will uni- 

 formly devour the eggs if they are not concealed by the 

 female. Darwin states that in a South American species of 

 Molothrus the instincts for securing proper care of the eggs 

 are so imperfect that numerous eggs are simply dropped on 

 the ground and abandoned. 



Many instincts are at first not clearly defined. The 

 young chick pecks at all sorts of small objects of good and 

 bad taste alike. The young lamb will follow any sort of 

 moving object of a certain size as well as its own mother. 

 It is said to suck indefinitely at a piece of wool unless guided 

 by some fortunate circumstance to the proper fount of 

 nutriment. Young terns and many other young birds will not 

 at first distinguish then- parents, but will cuddle under one's 

 hand in perfect confidence and contentment. They react 

 in much the same way to a great variety of large moving 

 objects. In most cases these mean the parent birds, and 

 the instinct of the young becomes directed to then- parents 

 because the latter were the first living objects coming 

 within their experience. Foster mothers of various kinds 

 are adopted by many .young birds and mammals as readily 

 as members of their own species. 



While many instincts exist in a completely developed state 

 when the animal first enters upon active life, others are 

 manifested only when it has reached a certain degree of 

 maturity. Such have been called by Lloyd Morgan " de- 

 ferred instinct s." Instinctive fear in birds may not appear 

 at first, but only after several days. Young nestling terns 

 which for a short time after hatching will cuddle contentedly 

 under one's hands, behave very differently before they are a 

 third grown. They then scuttle away in wildest alarm 

 upon one's approach and hide by crouching down in the grass, 

 where they will lie perfectly quiet. The instinct of feigning 



