4 THE INFANCY OF ANIMALS 



aspects to be considered, such as the relation which exists 

 between parent and offspring, for while some young animals 

 are jealously guarded by one, at any rate, of their parents, 

 others are orphaned before they are born, or are pitched 

 into the world, so to speak, to live or die as fate may decree. 

 The higher we get in the scale of creatures, the longer 

 the period of infancy, and the more the care displayed by 

 the parents for their young. All the mammals, without 

 exception, nurse their offspring, for a longer or shorter 

 period. Among the birds we find parasitic species, like 

 the cuckoos, which thrust the parental duties upon other 

 species : and some, like the megapodes, which leave the 

 incubation of their eggs to natural agencies such as the 

 heat generated by decaying vegetation, or that derived 

 from. hot springs. The reptiles show little or no parental 

 care ; but, strangely enough, the frogs and toads and their 

 kind, and many fishes, furnish us with cases of remarkable 

 solicitude, or apparent solicitude, for their offspring. 

 Since the insects stand still lower in the scale, it is the 

 more strange that we should find among them some of 

 the most wonderful devices for assuring the welfare of the 

 young to be met with in the animal kingdom — devices 

 which almost bafHe analysis, since, having regard to what 

 obtains among the higher groups, these tiny creatures 

 seem to be endowed with an intelligence and a solicitude 

 for the welfare of their offspring which are not exceeded even 

 by man himself. Yet we cannot interpret their behaviour 

 in such terms. But this is an aspect which belongs to 

 psychology, and is outside the aims of these pages. 



