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 their 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 their 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 instincts.” 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 
