INSTINCT AND INTELLIGENCE. 



it lives alone in burrows, which it excavates on the borders of 

 lakes and rivers ; but on the approach of winter, the animals quit 

 these retreats, and assemble together for the purpose of construct- 

 ing a common habitation for the winter season. It is in the most 

 solitary places that they display their architectural instinct. 



82. Two or three hundred having concerted together, select a 

 lake or river too deep to be frozen to the bottom, for the establish- 

 ment of their dwellings. They generally prefer a running stream 

 to stagnant water, because of the advantage it affords them as a 

 means of transport for the materials of their habitation. To keep 

 the water at the desired depth, they commence by constructing a 

 dam or weir in a curved form, the convexity being directed against 

 the stream. This is constructed with twigs and branches, curiously 

 interlaced, so as to form a sort of basket-work, the interstices 

 being filled with gravel and mud, and the external surface 

 plastered with a thick and solid coating of the same. This 

 embankment, the width of which, at its base, is commonly from 

 twelve to fourteen feet, lasts, when once constructed, from year to 

 year, the same troop of beavers always returning to pass the winter 

 under its shelter. Their labours after the first season are limited 

 to keeping it in repair ; they strengthen it from time to time by 

 new works, and restore whatever may be worn away by the action 

 of the weather. It is rendered more permanent by a vigorous 

 vegetation, which soon clothes its surface. 



83. Wherever stagnant water has been selected, this preliminary 

 labour becomes unnecessary, and the animals proceed at once to 

 build their village. But, as has been already observed, they are 

 subject in that case to an equivalent amount of labour in the 

 transport of the materials. 



When this preliminary work has been completed, they resolve 

 themselves into a certain number of families, and if the locality is 

 a new one, each family sets about the construction of its huts ; 

 but if they return to the village they inhabited a former year, 

 their labour is limited to the general repair and cleansing of the 

 village. 



The cabins composing it are erected against the dam, or upon 

 the edge of the water, and generally have an oval form. Their 

 internal diameter is six or seven feet, and their walls, like the 

 dam, constructed of twigs and branches, are plastered on both 

 sides with a thick coating of mud. The cabin, of which the 

 foundation is below the surface of the water, consists of a base- 

 ment and an upper storey, the latter being the habitation of the 

 animals, and the former serving as storeroom for provisions. 



The entrance to the cabin is in the basement story, and below 

 the level of the water. 

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