BEAVER AND NUTRIA 121 



When he selects a habitat, he builds a dam. He does this so he 

 will have deep water for a retreat against enemies, especially in 

 winter and time of drought. His entrance to his nest or house is 

 always below water ; but his dwelling is a shelf above the water 

 line. When he begins to construct the dam, it is true he brings 

 the soft clay and earth in his mouth for a foundation ; but it is not 

 true that he spanks the clay down with his tail for a trowel. The 

 only use he makes of his tail is as a rudder, when he swims, like 

 the fish, and as a balance when he sits up to saw wood with his teeth, 

 as a bird balances itself with its tail on a branch. Without the 

 tail, the bird's heavy breast in front of the feet would topple it 

 forward. If you doubt this, watch how fledglings cannot fly till 

 they get the tail feathers, how a hen has difficulty keeping her 

 balance on a roost when she is molting her tail feathers. Having 

 patted down a layer of earth with his paws, the beaver goes ashore 

 and cuts down young saplings. Cases are on record where he has 

 cut saplings almost 12 inches in diameter. If possible, these sap- 

 lings are so felled that they crash down where the dam is building. 

 If they don't fall in the right place, the beaver hauls them over by 

 his teeth. I don't know whether two beavers ever pull on the same 

 haul, for I have never seen them do it ; but I have seen saplings 

 in a dam that required the strength of more than one beaver, and 

 they have not been windfall. They may, however, have been afloat. 

 For such tasks, nature has provided the beaver with long curved 

 teeth, resembling more than anything else I know a pair of small 

 garden rose-bush shears. I have a pair of such beaver teeth taken 

 from a beaver trapped in Cumberland Lake region that would easily 

 span the forearm of a man, or leg of a small horse. More earth, 

 more sticks, more saplings complete the dam. The beaver then 

 constructs his house with similar methods. If the colony grows, 

 the dam will yearly grow with more workers, and the number of 

 houses will increase till the stream or lake literally backs water 

 and floods adjacent land. This happened in Algonquin Park, 

 Ontario, during the closed years, till settlers outside the limits of 



