THE BEAVERS OF NORTH AMERICA 75 



advantage to be gained by curves they make curves, 

 in other words they follow the lines of least resist- 

 ance, appreciating the fact that a straight line is the 

 shortest distance between two points. When the 

 canal leads from the pond across more or less level 

 ground to an abrupt hillside which is well- wooded, 

 they are not content with simply running their 

 canal to this hill, but they frequently make branches 

 on either side, these branches often extending 

 several hundred feet so that the beaver are able to 

 take their cuttings by way of the canals with the 

 least possible effort. In making the canals the 

 animals scoop out the earth with their hands and 

 put most of it on the banks. If the ditch runs 

 parallel to the hill or rising ground, most of the 

 earth is placed on the lower bank so that it will not 

 interfere with supply of surface water on which 

 they largely depend for keeping the canals suffi- 

 ciently deep. In the low lands there is seldom any 

 difficulty in the matter of water, as the seepage 

 naturally finds its way into the ditch, but in some 

 cases the beaver are confronted with the scarcity 

 of water and they resort to most ingenious methods 

 for overcoming the difficulty. They will search 

 the immediate vicinity for a stream however small, 

 or a living spring. This they will tap by means of 

 a narrow ditch which leads the water to the canal, 

 another example of the animals' careful reasoning. 

 Besides these long and ambitious canals which 

 were, I believe, first described by Morgan, and 



