THE PLAY OF ANIMALS. 155 



"As a matter of fact, no naturalist has yet been 

 able to prove that old birds instruct their young in 

 nest-building. It would be impossible for those that 

 nest but once, as the young can not be present when the 

 parents build; yet the next spring, when they are only 

 a year old, they go about the construction of their own 

 nest with as much assurance as if they had been in the 

 business a long time." * 



I cite Naumann next, who plainly indicates the two- 

 fold nature of the phenomenon: " We may well won- 

 der at the mysterious instinct that enables young birds 

 to build at their first attempt nests as perfect as those 

 of their parents, and similar to them in material, posi- 

 tion, and form; but it can not be denied that their art 

 can be brought to even greater perfection by means of 

 practice." f 



In inquiring now as to the connection between these 

 arts and the psychology of play, it becomes apparent 

 that building in general is not playful. The earthworks 

 of beavers, foxes, badgers, fish-otters, rabbits, etc., the 

 leafy arbours of many kinds of apes, the nests of the 

 perch, hedgehog, squirrel, field mouse, and bird serve 

 a purpose that is directly useful. But since all art has 

 at least some likeness to play, it follows that building 

 of this kind is not properly called art, any more than 

 the rude shelters of our primeval ancestors can be called 

 products of architecture. Only in special cases, then, can 

 we speak of playful building. Darwin sees such a case in 

 the well-known fact that caged birds often build nests 

 for amusement, when they have no occasion to use 



* A. and K. Muller, Wohnungen, Leben und Eigenthiimlich- 

 keiten der hoheren Thierwelt, 1869, p. 216. 



f Naturgeschichte der Vogel Deutschlands, i, p. 97. 



