The Builders. 'i2> 



it to shallow water, else some severe winter it would 

 get frozen into the ice, and the beavers starve in 

 their prison. Ten to fifteen feet usually satisfies their 

 instinct for safety ; but to get that depth of water, 

 especially on shallow streams, requires a huge dam 

 and an enormous amount of work, to say nothing 

 of planning. 



Beaver dams are solid structures always, built up 

 of logs, brush, stones, and driftwood, well knit together 

 by alder poles. One summer, in canoeing a wild, 

 unknown stream, I met fourteen dams within a space 

 of five miles. Through two of these my Indian and 

 I broke a passage with our axes ; the others were so 

 solid that it was easier to unload our canoe and make 

 a portage than to break through. Dams are found 

 close together like that when a beaver colony has 

 occupied a stream for years unmolested. The food- 

 wood above the first dam being cut off, they move 

 down stream ; for the beaver alwa)'s cuts on the 

 banks above his dam, and lets the current work for 

 him in transportation. Sometimes, when the banks 

 are such that a pond cannot be made, three or four 

 dams will be built close together, the back-water of 

 one reaching up to the one above, like a series of 

 locks on a canal. This is to keep the colony together, 

 and yet give room for play and storage. 



There is the greatest difference of opinion as to the 



