254 THE PLAY OF ANIMALS. 



able in mammals, some of which even in infancy make 

 efforts to produce the movements necessary for pairing, 

 a fact which can only be explained as practice for later 

 life. Such phenomena are common among young dogs 

 and apes, and Dr. Seitz, in Frankfort, noticed them in 

 an antelope only six weeks old. While there are cases, 

 especially among monkeys, where there is so much 

 excitement as to render the playful character doubt- 

 ful, still, as a rule, it is attributed to youthful sportive- 

 ness. According to Dr. Seitz, it sometimes happens in 

 these games that the sexes change their parts, the male 

 coqueting and the female pursuing. Chr. L. Brehm 

 has noticed this, too, in the case of the golden-crested 

 wren. 



Much detailed material has been collected by or- 

 nithologists to show that songs, dancing, and flying evo- 

 lutions are extensively practised by young birds in 

 their first autumn, too early to serve the purposes of 

 reproduction. This is genuine play, practice for in- 

 stinctive activity quite as much as are the chasing and 

 fighting of young animals. " The song of birds," says 

 the elder Brehm, "appears to be the expression of 

 love, for it begins with many shortly before pairing 

 and ceases altogether after it, and with those that sing 

 all through the summer, as the field lark does, the pair- 

 ing season lasts as long. Caged birds are no exception 

 to this, for most of them lose their natural or hereditary 

 song or never acquire it, as, for instance, the wood lark, 

 the red linnet, and many others. 



" Awakening love impels some birds in captivity to 

 sing as usual, and they also breed in that state, but the 

 majority lose their power to do the latter and sing only 

 as the effect of rich food and ennui. But the most 

 noteworthy thing about the whole subject is that their 



