l62 CASTOROIvOGIA. 



smaller bushes. Before cutting down a tree, they mark it all round 

 at the height at which they wish to cut it. They begin to cut at 

 the opposite side to which they intend the tree should fall, invariably 

 making it fall with the top to the water. Where they grow near 

 enough, they make them fall across the stream or dam, causing 

 many to suppose that they are so placed to form a bridge, whereby 

 they may cross from one side of the water to another. They do not 

 require a bridge, they can swim, and rather than cross over a pros- 

 trate tree they dive under it. My impression is they are so placed 

 to break the current of the water when the stream is flooded ; also if 

 convenient they take advantage of building a dam where some of the 

 trees lie across the water. Those lying across in their principal dam 

 are utilized in storing up their winter food, these stores being built 

 on the upper side of the trees, so that they cannot be swept awaj' 

 with the winter floods. 



" When cutting the trees they use their teeth, on the same prin- 

 ciple that a forester does an axe, always keeping plenty of open space, 

 so that they can cut past the centre of the tree on one side before 

 beginning on the other. It is in the latter end of autumn they com- 

 mence to cut down trees for winter food. Having cut them down 

 they speedily strip off the branches, cutting them into lengths to 

 suit their strength for dragging them away to the dam, where they 

 store them in different places near their house, so that they may 

 have sufiicient food, although the dam may be frozen over, or the 

 ground covered with snow. What is left of the trunks of the trees 

 that they cannot drag away, they feed on at leisure, eating the bark. 



' ' Besides the work above ground which I have tried to describe, 

 they have done a great amount of underground work, such as cutting 

 channels in their dams, and making burrows. These burrows they 

 make by cutting a road from the middle of the dam for several yards 

 into the dry ground, where they scoop out a dome-shaped burrow 

 from eight to ten inches above the level of the road, then cut a hole 

 through the surface and cover it over with sticks and grass so as to 

 act as a ventilator. Here they live and feed in security and content- 

 ment. Some of the roads to these burrows are from fifteen to twenty 



