Natural History 491 



suggestions, but the most important idea is that the play period 

 is the time for educating powers which are useful in after life. 

 Play is the young form of work a rehearsal without too great 

 responsibilities, when mistakes can be made without too severe 

 punishment. As Dr. Groos says, playing animals do not simply 

 play because they are young; they continue young in order that 

 they may play. In the course of ages playing instincts have been 

 established in many mammals, and they make for success. 

 The Story of the Weasel 



The Weasel (Putorius vulgaris) is one of the northern mam- 

 mals common to Europe, Asia, and North America. It is a first 

 cousin to the Stoat or Ermine, and an embodiment of virility. 

 The spare sinuous body and the long neck suggest the snake, and 

 the convergence simply means that the Weasel is adapted, like a 

 snake, to making its way through narrow passages. The Weasel 

 succeeds in virtue of a nimble brain, very keen senses, highly de- 

 veloped muscularity without any "spare flesh," and solicitous 

 maternal care; but it would be unscientific to overlook its extra- 

 ordinary courage. It will face up to a terrier, even to a man. It 

 will leap up and catch a partridge already on the wing. "A pair 

 will stand affectionately and nobly by each other in danger, and a 

 weasel mother will defend her young to the last gasp." A weasel 

 will explore a house and defy the house-cat; it will bluff a lot of 

 roosting hens that could have pecked it to pieces; whining and 

 daring, snarling and bristling, it will retrieve its young ones from 

 under the feet of man. 



16 

 Social Mammals 



Many mammals are gregarious and some go a step further 

 and illustrate some measure of communal or corporate life. It is 

 difficult to draw any hard-and-fast line. Gregariousness is illus- 

 trated by cattle, deer, wild horses, rabbits, kangaroos, and many 

 more. The chief advantage is in the strength that numbers give 



