Once a large tree is on the ground, the limbs are trimmed off and the trunk is cut into sections sufficiently small to be dragged, rolled, or pushed to the water, where transportation is easy. The young beaver that I have seen cutting trees have worked in leisurely manner, in contrast with the work of the old ones. After giving a few bites, they usually stop to eat a piece of the bark, or to stare listlessly around for a time. As workers, young beaver appear at their best and liveliest when taking a limb from the hillside to the house in the pond. A young beaver will catch a limb by one end in his teeth, and, throwing it over his shoulder in the attitude of a puppy racing with a rope or a rag, make off to the pond. Once in the water, he throws up his head and swims to the house or the dam with the limb held trailing out over his back. The typical beaver-house seen in the Rockies at the present time stands in the upper edge of the pond which the beaver-dam has made, near where the brook enters it. Its foundation is about eight feet across, and it stands from five to ten feet in height, a rude cone in form. Most houses are made of sticks and mud, and are apparently put up with little thought for the living-room, which is later dug or gnawed from the interior. The entrance to the house is below water-level, and commonly on the bottom of the lake. Late each autumn, the house is plastered on the outside with mud, and I am inclined to believe that this plaster is not so much to increase the warmth of the house as to give it, when the mud is frozen, a strong protective armor, an armor which will prevent the winter enemies of the beaver from breaking into the house. Each autumn beaver pile up near by the house, a large brush-heap of green trunks and limbs, mostly of aspen, willow, cottonwood, or alder. This is their granary, and during the winter they feed upon the green bark, supplementing this with the roots of water-plants, which they drag from the bottom of the pond. Along in May five baby beaver appear, and a little later these explore the pond and race, wrestle, and splash water in it as merrily as boys. Occasionally they sun themselves on a fallen log, or play together there, trying to push one another off into the water. Often they play in the canals that lead between ponds or from them, or on the "slides." Toward the close of summer, they have their lessons in cutting and dam-building. [Illustration: A BEAVER-HOUSE Supply of winter food piled on the right]