All work is done with mouth and fore paws, and not the tail. This has been finally determined by observing the Marquis of Bute's colony of beavers. If the family--the old parents and three seasons' offspring--be too large for the house, new chambers are added. In height the house is seldom more than five feet from the base, and the width varies. In building a new dam they begin under water, scooping out clay, mixing this with stones and sticks for the walls, and hollowing out the dome as it rises, like a coffer-dam, except that man pumps out water and the beaver scoops out mud. The domed roof is given layer after layer of clay till it is cold-proof. Whether the houses have one door or two is disputed; but the door is always at the end of a sloping incline away from the land side, with a shelf running round above, which serves as the living-room. Differences in the houses, breaks below water, two doors instead of one, platforms like an oven instead of a shelf, are probably explained by the continual abrasion of the current. By the time the ice forms the beavers have retired to their houses for the winter, only coming out to feed on their winter stores and get an airing. But this terrible thing has happened; and the young beavers huddle together under the ice of the canal, bleating with the cry of a child. They are afraid to run back; for the crunch of feet can be heard. They are afraid to go forward; for the dog is whining with a glee that is fiendish to the little beavers. Then a gust of cold air comes from the rear and a pole prods forward. The man has opened a hole to feel where the hiding beavers are, and with little terrified yelps they scuttle to the very end of the runway. By this time the dog is emitting howls of triumph. For hours he has been boxing up his wolfish ferocity, and now he gives vent by scratching with a zeal that would burrow to the middle of earth. The trapper drives in more stakes close to the blind end of the channel, and cuts a hole above the prison of the beaver. He puts down his arm. One by one they are dragged out by the tail; and that finishes the little beaver--sacrificed, like the guinea-pigs and rabbits of bacteriological laboratories, to the necessities of man. Only, this death is swifter and less painful. A prolonged death-struggle with the beaver would probably rob the trapper of half his fingers. Very often the little beavers with poor fur are let go. If the dog attempts to capture the frightened runaways by catching at the conspicuous appendage to the rear, that dog is likely to emerge from the struggle minus a tail, while the beaver runs off with two.