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houses and winter food and many other things. The grown-up males have brought their mates back to the old home; the females have found their places in other family groups. It is then that the beaver begins to be busy.

His first concern is for a stout dam across the stream that will give him a good-sized pond and plenty of deep water. To understand this, one must remember that the beaver intends to shut himself in a kind of prison all winter. He knows well that he is not safe on land a moment after the snow falls; that some prowling lucivee or wolverine would find his tracks and follow him, and that his escape to water would be cut off by thick ice. So he plans a big claw-proof house with no entrance save a tunnel in the middle, which leads through the bank to the bottom of his artificial pond. Once this is frozen over, he cannot get out till the spring sun sets him free. But he likes a big pond, that he may exercise a bit under water when he comes down for his dinner; and a deep pond, that he may feel sure the hardest winter will never freeze down to his doorway and shut him in. Still more important, the beaver's food is stored on the bottom; and it would never do to trust it to shallow water, else some severe winter it would get frozen into the ice, and the beavers starve in their prison. Ten to fifteen feet usually satisfies their instinct for safety; but to get that depth of water, especially on shallow streams, requires a huge dam and an enormous amount of work, to say nothing of planning.

Beaver dams are solid structures always, built up of logs, brush, stones, and driftwood, well knit together by alder poles. One summer, in canoeing a wild, unknown stream, I met fourteen dams within a space of five miles. Through two of these my Indian and I broke a passage with our axes; the others were so solid that it was easier to unload our canoe and make a portage than to break through. Dams are found close together like that when a beaver colony has occupied a stream for years unmolested. The food-wood above the first dam being cut off, they move down stream; for the beaver always cuts on the banks above his dam, and lets the current work for him in transportation. Sometimes, when the banks are such that a pond cannot be made, three or four dams will be built close together, the back-water of one reaching up to the one above, like a series of locks on a canal. This is to keep the colony together, and yet give room for play and storage.

There is the greatest difference of opinion as to the intelligence displayed by the beavers in choosing a site for their dam, one observer claiming skill, ingenuity, even reason for the beavers; another claiming a mere instinctive haphazard piling together of materials anywhere in the stream. I have seen perhaps a hundred different dams in the wilderness, nearly all of which were well placed. Occasionally I have found one that looked like a stupid piece of work—two or three hundred feet of alder brush and gravel across the widest part of a stream, when, by building just above or below, a dam one-fourth the length might have given them better water. This must be said, however, for the builders, that perhaps they found a better soil for digging their tunnels, or a more convenient spot for their houses near their own dam; or that they knew what they wanted better than their critic did. I think undoubtedly the young beavers often make mistakes, but I think also, from studying a good many dams, that they profit by disaster, and build better; and that on the whole their mistakes are not proportionally greater than those of human builders.

Sometimes a dam proves a very white elephant on their hands. The site is not well chosen, or the stream difficult, and the restrained water pours round the ends of their dam, cutting them away. They build the dam longer at once; but again the water pours round on its work of destruction. So they keep on building, an interminable structure, till the frosts come, and they must cut their wood and tumble their houses together in a desperate hurry to be ready when the ice closes over them.

But on alder streams, where the current is sluggish and the soil soft, one sometimes finds a wonderfully ingenious device for remedying the above difficulty. When the dam is built, and the water deep enough for safety, the beavers dig a canal around one end of the dam to carry off the surplus water. I know of nothing in all the woods and fields that brings one closer in thought and sympathy to the little wild folk than to come across one of these canals, the water pouring safely through it past the beaver's handiwork, the dam stretching straight and solid across the stream, and the domed houses rising beyond.

Once I found where the beavers had utilized man's work. A huge log dam had been built on a wilderness stream to secure a head of water for driving logs from the lumber woods. When the pines and fourteen-inch spruce were all gone, the works were abandoned, and the dam left—with the gates open, of course. A pair of young beavers, prospecting for a winter home, found the place and were suited exactly. They rolled a sunken log across the gates for a foundation, filled them up with alder bushes and stones, and the work was done. When I found the place they had a pond a mile wide to play in. Their house was in a beautiful spot, under a big hemlock; and their doorway slanted off into twenty feet of water. That site was certainly well chosen.

Another dam that I found one winter when caribou-hunting was wonderfully well placed. No engineer could have chosen better. It was made by the same colony the lynx was after, and just below where he went through his pantomime for my benefit; his tracks were there too. The barrens of which I spoke are treeless plains in the northern forest, the beds of ancient shallow lakes. The beavers found one with a stream running through it; followed the stream down to the foot of the barren, where two wooded points came out from either side and almost met. Here was formerly the outlet; and here the beavers built their dam, and so made the old lake over again. It must be a wonderfully fine place in summer—two or three thousand acres of playground, full of cranberries and luscious roots. In winter it is too shallow to be of much use, save for a few acres about the beavers' doorways.

There are three ways of dam-building in general use among the beavers. The first is for use on sluggish, alder-fringed streams, where they can build up from the bottom. Two or three sunken logs form the foundation, which is from three to five feet broad. Sticks, driftwood, and stout poles, which the beavers cut on the banks, are piled on this and weighted with stones and mud. The stones are rolled in from the bank or moved considerable distances under water. The mud is carried in the beaver's paws, which he holds up against his chin so as to carry a big handful without spilling. Beavers love such streams, with their alder shade and sweet grasses and fringe of wild meadow, better than all other places. And, by the way, most of the natural meadows and half the ponds of New England were made by beavers. If you go to the foot of any little meadow in the woods and dig at the lower end, where the stream goes out, you will find, sometimes ten feet under the surface, the remains of the first dam that formed the meadow when the water flowed back and killed the trees.

The second kind of dam is for swift streams. Stout, ten-foot brush is the chief material. The brush is floated down to the spot selected; the tops are weighted down with stones, and the butts left free, pointing down stream. Such dams must be built out from the sides, of course. They are generally arched, the convex side being up stream so as to make a stronger structure. When the arch closes in the middle, the lower side of the dam is banked heavily with earth and stones. That is shrewd policy on the beaver's part; for once the arch is closed by brush, the current can no longer sweep away the earth and stones used for the embankment.

The third kind is the strongest and easiest to build. It is for places where big trees lean out over the stream. Three or four beavers gather about a tree and begin to cut, sitting up on their broad tails. One stands above them on the bank, apparently directing the work. In a short time the tree is nearly cut through from the under side. Then the beaver above begins to cut down carefully. With the first warning crack he jumps aside, and the tree falls straight across where it is wanted. All the beavers then disappear and begin cutting the branches that rest on the bottom. Slowly the tree settles till its trunk is at the right height to make the top of the dam. The upper branches are then trimmed close to the trunk, and are woven with alders among the long stubs sticking down from the trunk into the river bed. Stones, mud, and brush are used liberally to fill the chinks, and in a remarkably short time the dam is complete.

When you meet such a dam on the stream you are canoeing don't attempt to break through. You will find it shorter by several hours to unload and make a carry.

All the beaver's cutting is done by chisel-edged front teeth. There are two of these in each jaw, extending a good inch and a half outside the gums, and meeting at a sharp bevel. The inner sides of the teeth are softer and wear away faster than the outer, so that the bevel remains the same; and the action of the upper and lower teeth over each other keeps them always sharp. They grow so rapidly that a beaver must be constantly wood cutting to keep them worn down to comfortable size.

Often on wild streams you find a stick floating down to meet you showing a fresh cut. You grab it, of course, and say: "Somebody is camped above here. That stick has just been cut with a sharp knife." But look closer; see that faint ridge the whole length of the cut, as if the knife had a tiny gap in its edge. That is where the beaver's two upper teeth meet, and the edge is not quite perfect. He cut that stick, thicker than a man's thumb, at a single bite. To cut an alder having the diameter of a teacup is the work of a minute for the same tools; and a towering birch tree falls in a remarkably short time when attacked by three or four beavers. Around the stump of such a tree you find a pile of two-inch chips, thick, white, clean cut, and arched to the curve of the beaver's teeth. Judge the workman by his chips, and this is a good workman.

When the dam is built the beaver cuts his winter food-wood. A colony of the creatures will often fell a whole grove of young birch or poplar on the bank above the dam. The branches with the

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