not uncommon. More than one colony has com- 

 menced a dam apparently without knowing that 

 there was not sufficient available material to com- 

 plete it. Others have built in the wrong places, 

 and have thus failed to flood the area which they 

 desired to reach or cover with water. Occasion- 

 ally the difficulties of construction have been too 

 great for the beaver who attempted it, and the 

 dam has been abandoned in an incomplete state. 

 Now and then a weak dam breaks, or a strong 

 one is swept out by a flood. 



But why do beaver need or want the pond which 

 the dam forms ? They need it for the purpose of 

 maintaining water of sufficient depth and area to 

 enable them to move about in safety, and to trans- 

 port their food-supplies with the greatest ease. 

 Above all, the pond is a place of refuge into which 

 the beaver can constantly plunge and have secur- 

 ity from his numerous and ever watchful enemies. 

 The house-entrance must be kept water-covered. 

 In the water the beaver is in his element. On the 

 land he is a child lost in the wilds. He has ex- 

 tremely short legs and a heavy body. His make- 

 up fits him for movement in the water. He is a 



68 



