THE PLAY OF ANIMALS. 157 



courtship, as if trying to take something up, others will 

 throw little stones behind them, and still others carry 

 about on their beaks a small feather of the adored one. 

 The action of the wren described above is only one 

 step further in the same direction, and we find its cul- 

 mination in the wonderful pleasure-house of the bower 

 bird. Another manifestation of it is found in the fact 

 that during the time of their courtship many female 

 birds allow themselves to be fed by the male, just as the 

 young are later on. 



But more important for our purpose are the strange 

 methods of building ornamentation employed by some 

 animals. If no other meaning can be discovered for 

 them, they may very properly be regarded as playful. 

 I know of only two instances in mammals, and the first 

 of these is imperfectly vouched for and dubious. Dar- 

 win says that the viscacha, a South American rodent, 

 has the remarkable habit of collecting at the mouth of 

 its burrow every portable object within its reach, so 

 that heaps of stones, bones, thistle stalks, lumps of earth, 

 dry dung, etc., are found near their holes. It is even 

 related of a traveller who lost his watch in the region 

 that he recovered it by searching among the viscacha 

 mounds along the way.* 



Hudson corroborates these reports, and finds a use 

 for the habit : " For as the viscachas are continually 

 deepening and widening their burrows, the earth thrown 

 out soon covers these materials, and so assists in raising 

 the mounds," which protect their dwellings from over- 

 flow, f He further remarks that these animals always 

 build in an open plain, on even, close-shaven turf, where 



* Darwin, Journey around the World. 

 f The Naturalist in La Plata, p. 304. 



