102 



MR. It. I. POCOCK ON THE WORK OF 



In the evening of the flay on which the burrow was opened 

 one of the beavers started to repair the damage done, using 

 straw, branches, and mud for the purpose. The task occupied 

 him off and on the whole of the day following. He dug up the 

 wet clay from the bottom of the burrow and plastered it with his 

 paws over the straw and branches which he had previously laid in 

 place to roof the open channel. 



From that date until the summer of 1916 the burrow was left 

 undisturbed and two litters were born in it. The beavers,' how- 

 ever, were never idle. Working from the pool, at the entrance of 

 the burrow, they dug out a channel in an opposite direction from 

 the first, but roughly in the same line for a few yards, then 

 turned it with a sharp bend towards the artificial pond in the 

 centre of the enclosure. This channel was roofed over in the 

 same way as the first. In the meantime they had excavated a 

 trench up against the concrete wall of this pond on the side where 

 the burrow was situated, and the roofed-in channel was continued 

 till it communicated with this trench, which was deep enough for 

 the beavers to swim in except at one or two places on the margin 

 where shallow landing-places were made. 



So long as the beavers were supplied with straw, branches, and 

 logs, they employed them continually for strengthening the roof 

 of the burrow or heightening the roof of the terminal portion up 

 against the fence. When the enclosure was done away with in 

 1916, this portion where the burrow ended was found to consist 

 of a comparatively large chamber partly filled with water; but at 

 the very end towards the trunk of the witch elm above referred 

 to, "there was a flat dry platform above the level of the water and 

 about large enough to accommodate two beavers and their young. 

 There was no bedding on this platform, merely a scanty covering 

 of wood-chips. This part of the burrow was ventilated through 

 chinks in the fence left open by the beavers, and from it a narrow 

 passage, ending blindly, ran in the direction of the trench, and 

 would probably have been carried through to it, giving the 

 burrow a second entrance. 



The main points in the structure of the burrow are shown in 

 the plan of the enclosure (fig. 1, p. 101). The circular central 

 area is the brick-house surrounded by the concrete pond, and the 

 mud path is a beaten track along which the beavers used to carry 

 the mud to pile up against the fence. 



I have watched the beavers at work night after night, and 

 can confirm the observation of others as to their methods and 

 activities. They carry mud in their fore-paws tucked up against 

 the throat and chin and walk the while flat-footed on their hind 

 feet, with a kind of awkward waddle, the tail trailing behind and 

 acting as a support and balance. Mud is laid on with the fore- 

 paws to fill up chinks between branches and left to dry. It is 

 never smeared over or pressed down with the tail, but sometimes 

 it is jammed tightly home with the muzzle. 



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