84 SKETCH or THE HISTORY OF MAMMALIA. 



late in the autumn as possible, even when the frost has 

 set in, as by this means it soon becomes frozen as hard as 

 stone, and prevents their most formidable enemy, the wol- 

 verene or "glutton, from disturbing them during the winter. 

 In laying on this coat of mud they do not use their broad 

 flat tails, as has been asserted — a mistake which has 

 arisen from their habit of giving a flap with the tail when 

 plunging from the outside of the house into the water, 

 and when they are startled, as well as at other times. 

 The houses when complete have a dome-like figure, with 

 walls several feet thick, and emerging from four to six 

 feet above the water. The only entrance is deep under 

 water, below a projection called the "angle" by the 

 hunters, and beyond the reach of the frost : near this, 

 also under water, is laid up their winter store, a mass of 

 branches of billows and other trees, on the bark of 

 which they feed. These they stack up, sinkuig each 

 layer by means of mud and stones, and often accumulate 

 more than a cartload of materials. Besides these winter- 

 houses, in which they are shut up during tlie severities 

 of the season, they have always a number of holes in the 

 banks which serve them as places of retreat when any 

 injury is offered to their houses, and in these they are 

 generally taken. The entrance to these holes is deep 

 below the water, which fills a great part of the vault 

 itself. When the hunter forces the houses of the beaver 

 in winter (the hunting season), the animals swim beneath 

 the ice to these i-etreats, the entrances of which are disco- 

 vered by striking the ice along the banks with an iron 

 ice-chisel, the sound indicating to practised ears the 

 exact spot : they cut a hole in the ice and surprise their 

 booty. During the summer the beavers roam about at 

 pleasure, and it is during this season that they fell the 

 wood necessary for repairing their houses and dams, or 

 for building others, commencing the latter about the end 

 of August. Such is the strength and sharpness of their 

 teeth, that they will lop off" a branch as thick as a walk- 

 ing-stick at a single effort, and as cleanly as if cut with a 

 pruning- knife. Larger stems they gnaw all round, taking 

 care that their fall shall be towards or into the water. 



