46 ROMANCE OF THE BEAVER 



possible precaution not only to conceal myself, but 

 to select a position down wind of the dam, where 

 I remained sometimes during the greater part of 

 the night. 



When a dam is abandoned, it is soon worn down 

 by animals using it as a roadway, or it is overgrown 

 by alders and willows, whose roots cause a. certain 

 amount of leakage, so that the pond is gradually 

 drained, and in a very few years there is little to 

 show that a dam ever existed in the place. 



Among the many interesting features of the 

 dams, there is one which speaks most highly for 

 the builder's intelligence. That is the method 

 adopted for taking care of the overflow. In most 

 cases, the water finds its way through the loose 

 brush near the crown. This is well enough under 

 normal conditions, but when the dam is on a good- 

 sized stream so that there is a large volume flowing 

 from the pond, the beaver frequently make a spill- 

 way or opening a few feet wide, and deep according 

 to the conditions. These openings are quite clearly 

 defined, and are evidently made with a full under- 

 standing of their purpose. For when there is a 

 scarcity of water, the intelligent animals close the 

 opening as much as may be necessary. This 

 shows how thoroughly they realise what they are 

 doing when building their dams, and how they 

 understand the value of controlling the outlet of 

 the water. They a,re always ready to grapple with 

 new problems, and no ordinary contingency appears 



