16 ROMANCE OF THE BEAVER 
soaked grass, roots and mud are employed to fill 
in the openings, with the result of making the 
whole structure nearly light-tight and practically 
water-tight. As soon as the nights are cold enough 
to freeze, the surface is plastered over with several 
inches of mud which is usually gathered from the 
pond or river bottom. This fact, has, I know 
been questioned even by such authorities as 
Thompson Seton, who in his excellent book* says: 
“It (the beaver) never plasters the lodge with mud 
outside. All lodges are finished outside with 
sticks.” This is more or less true during the 
earlier part of the season, but in most cases which 
have come under my observation the houses were 
thickly plastered over immediately before the 
actual coming of winter.t The mud, of course, 
freezes into a solid and intensely hard protective 
coating—so hard that even the wolves cannot tear 
a way through; but it breaks away early in the 
* “Tiife Histories of Northern Animals.” 
t Enos A. Mills, “In Beaver World,” states that, “In Montana 
of twenty-seven beaver houses which I examined twenty-one 
received mud covering.” In Morgan’s “The American Beaver ” 
there is the following convincing statement: ‘‘ Late in the fall, 
each season, the sides of their lodges, nearly to the summit, are 
in some cases plastered over with mud, which soon freezing, 
materially increases their strength.’ And James Hearne (in - 
(1769—1772) states that: “It is a great part of the policy of 
these animals to cover, to plaster, as it is usually called, the out- 
side of their houses every fall with fresh mud, and as late as 
possible in the autumn, even when the frost becomes pretty 
severe.’ 
