Notes on the Habits of the Beaver. 



329 



The following Communications were then read : — 



1. Notes on the Habits of the Beaver. By an Eye-witness, James 

 M'Kenzie, Esq., an Officer in the Hudson's Bay Company Service. 

 Communicated by Andrew Murray, Esq. 



The Beaver is found over a wide extent of country on the American 

 continent, extending east and west from the Atlantic to the Pacific, and 

 probably from Lat. 48° to 54° north ; but on the slopes of the Rocky Moun- 

 tains, where the climate is comparatively mild, he is met with much 

 further north and south. My object, however, is not so much to define 

 his geographical limits, as to make a few notes on his habits. Beavers 

 build occasionally on the shores of lakes, but prefer the banks of rivers and 

 streams. They go generally in pairs ; and having selected a convenient 

 site near the banks of the river, the two clear a circular piece of ground, 

 generally 6 feet in diameter, carefully removing everything on the sur- 

 face. This done, they carry in their arms, walking on the hind feet, 5 

 to 10 lbs. of strong clay from the river, and deposit it to a width of 2 feet 

 all round the circle, thus making the diameter 4 feet ; then collecting long 

 grass or branches of willow, they mix up the whole well together, so as to form 

 a good foundation. In this way they build the walls to a height of about 

 10 feet, gradually narrowing ; and the whole has a rounded form, some- 

 what like an oven. Unless they bad some means of plastering or smooth- 

 ing down the mud walls, the rain would certainly wear them away in a 

 short time ; and although it is supposed that the beaver never uses his 

 tail as a trowel, I have it from the authority of eye-witnesses that he does 

 so — in fact, Nature has furnished the animal with the tool ready made to 

 his hand. After he has laid the foundation, and, indeed, in process of lay - 

 ing it, before the clay gets dry, he uses the trowel ; and when the wall is 

 raised to a certain height, he goes round the circle, carefully plastering 

 every load he carries from the river and lays on his house. The lodge 

 has neither doors nor windows, and the finishing hand is not put to it till 

 he is far advanced with his bridge, or perhaps until he has completed it. 

 Before the house can be completed, a subterranean passage is excavated 

 from its centre to the dam or pond, and this at a depth varying from 2 to 

 6 feet, depending on the difference of level between the river and house. 

 He then strews his floor with thin strips of willow tree, cut by him in the 

 form of carpenter's shavings, for his winter's bed. The construction of 

 the bridge shows even more ingenuity than the construction of the house, 

 and is of various lengths, depending on the size of the stream. When 

 only a few feet wide, the wall goes straight from bank to bank at right 

 angles to the current ; when larger, or about 40 feet w T ide, it is formed of 

 a single curve ; but when the river to be bridged is from 100 to 120 feet 

 wide, the wall is formed into a series of curves, or undulations as it were. 

 He understands pretty well the properties of straight and curved lines in 

 his engineering works, and knows the mode best suited to the circum- 

 stances in which he is placed. If his domicile is situated on a wide stream, 

 he adopts that mode of construction which is best adapted to withstand 

 the pressure of a great body of water and ice on the opening of the naviga- 

 tion in the spring. The wail is about 12 feet high and 9 feet wide at 

 bottom, but on the side exposed to the current it slopes with the stream, 

 forming, perhaps, an angle of about 40°. At any rate, while the wall is 

 about 9 feet wide at bottom, it is only 1 foot wide at top. Pie selects 

 for the foundation pieces or logs of timber which are water-soaked ; but 

 if he cannot find enough of these, any wood, either green or dry, will do, 

 covering them with large stones, to prevent their rising to the surface. 

 But logs thus placed on one another across a stream could not be so well 



