At times Hamoosabik must be sadly puzzled by his primitive observation, especially where man interferes with nature, leaving strange marks to which animals are not accustomed. Twice have I found surprising lodges built on the shore of artificial ponds, where a new high-water mark showed above the old flood level. These ponds had been made by lumbermen, who raised the water five or six feet in order to have a “head” for driving their logs. When their work ended they opened the gates of their dam and went away, leaving the pond to return to its former size. Then beavers came back to the solitude, and used the pond for a winter home. When they examined the shores before building their lodge (it is their habit to explore a place thoroughly), they must have seen the dead trees, the barked trees, the line of jetsam high and dry, all plainly indicating where the flood had been. But there was nothing to tell the beavers why the water had risen so much higher here than in other lakes, and they were evidently guided by such signs as they could understand. In each case they built their lodge not on low swampy ground, as they habitually do, but on a dry bank, and the dome of the lodge rose just above the artificial water level.
Another question meets you when you examine Hamoosabik’s digging operations, especially his canals, which are the most intelligent of all his works. It is noticeable that beavers cut their food-wood above their storehouse whenever that is possible, and so make use of the current in transportation; but when the selected grove of poplars stands back from the shore, then the beavers dig a canal from their pond or stream to their source of supply. And a very remarkable canal it is, with clean-cut sides, about two feet wide and a little less in depth, in which the water stands quiet, showing a perfect level.
Such a canal goes straight as a string in one place, or winds around an obstruction in another, always following the most even ground; and it ends at the beaver’s grove, or as near as he can get and bring the water with him. He is a powerful worker, handling logs of astonishing size with the help of his mate; but you will not catch him rolling or dragging a thing if he can possibly float it. Even the stones which he uses in weighting his dam are moved under water, where they are much lighter than on land.
It is commonly assumed that Hamoosabik digs a canal in order to have an easy way of transporting his wood. He certainly uses it for that purpose; but he has another end in view, I think, when he begins his digging. It should be remembered that beavers, though tireless workers, like to loaf and play as well as other wood folk. They never work for the sake of working; yet one often sees a canal that represents an enormous amount of labor, so apparently superfluous that one wonders what the animals were thinking of. It is not merely the length of such a canal which puzzles one, but the roundabout course it must follow in order to keep on level ground. It sometimes happens, when food-wood stands on a hillock within a few rods of the pond, that the beavers will run their canal four or five times that distance, avoiding the rising ground and approaching the hill from the farther side. Your first thought, when you meet such a work, is that the animals could have hauled their wood down the easy slope in half the time they spent preparing for water transportation.
I recall one canal on which a deal of labor, the most skillful I ever saw in an animal, had been expended for what seemed a very small result. The beavers were building a dam on a trout stream bordered by primeval forest. About two hundred yards west of the stream the forest opened upon a little swale, in which grew plentiful alders, the beavers’ favorite building material. Evidently they found the alders when they explored the neighborhood, and decided they must have them. Their dam was a small one, and it would have been a simple matter to drag a sufficient supply of brush through the woods; but the beavers chose the harder task of digging a six-hundred-foot canal from the stream to the alder swale.
That canal was an amazing piece of work. Not ten yards of it were straight, and could not be straight because of trees or other obstacles; yet it held a course true as a compass from the pool above the dam to the objective point, which was hidden from sight in the big woods. In one place it ran under an immense tree that stood on a hummock. The central roots were cut away; but other great roots were left arching down on either side, supporting the tree as a living bridge. In another place a pine log twenty-inches thick, its heart still sound, was encountered beneath the mossy mold, squarely athwart the course of the canal. The beavers had cut through other logs that lay on the surface; but the buried pine did not interfere with their plan or purpose, apparently. After clearing away the earth on top of the log, they dug an opening beneath it and continued their ditch on the other side, thus allowing the water to flow over and under the obstruction. When the time came for towing their material through the canal, the slippery top of the pine offered hardly more resistance than the water itself.
Here the beavers had not only spared themselves unnecessary labor, but had shown a rare degree of intelligence in the process. So the question arises, Why did they bother with a canal at all, since they move material overland on occasion, and they could have dragged a supply of alders to the stream with half the effort required for their extraordinary digging?
I had camped weeks near this beaver family, puzzled by their work, before answer came from an unexpected actor. Lynxes were uncommonly abundant; they prowl by night, when the beaver works, and they are ravenously fond of young-beaver meat. They suggest the fact that all the beaver’s works are intended primarily for security, and that the element of safety is probably uppermost in his mind when he digs a canal. On land he is slow, clumsy, almost defenseless; in the water he is at home, a match for any animal at either swimming or fighting. Undoubtedly he feels safer in his canal, where he can defend himself or get away under water, than he can possibly feel in woods or meadows that offer him no refuge from his enemies. So he always starts digging at the stream’s edge, and works toward his grove of wood (never in the opposite direction, from grove to stream), and so the friendly water goes with him, filling his canal as fast as he digs it, offering him a way of escape at every instant.
It is significant, in this connection, that beavers do not use a pond that has no outlet or inlet. Hundreds of such spring-fed ponds are scattered through the north, some of them desirable from a beaver’s viewpoint; yet I have never found a sign to indicate that Hamoosabik has visited them. But if the pond have even a trickle of water running out of it, he will surely find it, no matter how distant it may be. The method is very simple, I think. Swimming up or down river on his endless exploration (for Hamoosabik is the pioneer among wood folk, forever pushing out himself or sending forth his progeny to new regions), he catches a flavor of different water, and follows it from river to brook, from brook to runlet, till he finds the pond it came from. And if he likes the place, after exploring all its watershed, he will bring his mate or family there for winter quarters.