VI. THE BUILDERS.

[Illustration]

A curious bit of wild life came to me at dusk one day in the

wilderness. It was midwinter, and the snow lay deep. I was sitting

alone on a fallen tree, waiting for the moon to rise so that I could

follow the faint snowshoe track across a barren, three miles, then

through a mile of forest to another trail that led to camp. I had

followed a caribou too far that day, and this was the result--feeling

along my own track by moonlight, with the thermometer sinking rapidly

to the twenty-below-zero point.

There is scarcely any twilight in the woods; in ten minutes it would

be quite dark; and I was wishing that I had blankets and an axe, so

that I could camp where I was, when a big gray shadow came stealing

towards me through the trees. It was a Canada lynx. My fingers gripped

the rifle hard, and the right mitten seemed to slip off of itself as I

caught the glare of his fierce yellow eyes.

But the eyes were not looking at me at all. Indeed, he had not noticed

me. He was stealing along, crouched low in the snow, his ears back,

his stub tail twitching nervously, his whole attention fixed tensely

on something beyond me out on the barren. I wanted his beautiful skin;

but I wanted more to find out what he was after; so I kept still and

watched.

At the edge of the barren he crouched under a dwarf spruce, settled

himself deeper in the snow by a wriggle or two till his feet were well

under him and his balance perfect, and the red fire blazed in his eyes

and his big muscles quivered. Then he hurled himself forward--one,

two, a dozen mighty bounds through flying snow, and he landed with a

screech on the dome of a beaver house. There he jumped about, shaking

an imaginary beaver like a fury, and gave another screech that made

one's spine tingle. That over, he stood very still, looking off over

the beaver roofs that dotted the shore of a little pond there. The

blaze died out of his eyes; a different look crept into them. He put

his nose down to a tiny hole in the mound, the beavers' ventilator,

and took a long sniff, while his whole body seemed to distend with the

warm rich odor that poured up into his hungry nostrils. Then he rolled

his head sadly, and went away.

Now all that was pure acting. A lynx likes beaver meat better than

anything else; and this fellow had caught some of the colony, no

doubt, in the well-fed autumn days, as they worked on their dam and

houses. Sharp hunger made him remember them as he came through the

wood on his nightly hunt after hares. He knew well that the beavers

were safe; that months of intense cold had made their two-foot mud

walls like granite. But he came, nevertheless, just to pretend he had

caught one, and to remember how good his last full meal smelled when

he ate it in October.

It was all so boylike, so unexpected there in the heart of the

wilderness, that I quite forgot that I wanted the lynx's skin. I was

hungry too, and went out for a sniff at the ventilator; and it smelled

good. I remembered the time once when I had eaten beaver, and was glad

to get it. I walked about among the houses. On every dome there were

lynx tracks, old and new, and the prints of a blunt nose in the snow.

Evidently he came often to dine on the smell of good dinners. I looked

the way he had gone, and began to be sorry for him. But there were the

beavers, safe and warm and fearless within two feet of me, listening

undoubtedly to the strange steps without. And that was good; for they

are the most interesting creatures in all the wilderness.

Most of us know the beaver chiefly in a simile. "Working like a

beaver," or "busy as a beaver," is one of those proverbial

expressions that people accept without comment or curiosity. It is

about one-third true, which is a generous proportion of truth for a

proverb. In winter, for five long months at least, he does nothing but

sleep and eat and keep warm. "Lazy as a beaver" is then a good figure.

And summer time--ah! that's just one long holiday, and the beavers are

jolly as grigs, with never a thought of work from morning till night.

When the snow is gone, and the streams are clear, and the twitter of

bird songs meets the beaver's ear as he rises from the dark passage

under water that leads to his house, then he forgets all settled

habits and joins in the general heyday of nature. The well built house

that sheltered him from storm and cold, and defied even the wolverine

to dig its owner out, is deserted for any otter's den or chance hole

in the bank where he may sleep away the sunlight in peace. The great

dam, upon which he toiled so many nights, is left to the mercy of the

freshet or the canoeman's axe; and no plash of falling water through a

break--that sound which in autumn or winter brings the beaver like a

flash--will trouble his wise little head for a moment.

All the long summer he belongs to the tribe of Ishmael, wandering

through lakes and streams wherever fancy leads him. It is as if he

were bound to see the world after being cooped up in his narrow

quarters all winter. Even the strong family ties, one of the most

characteristic and interesting things in beaver life, are for the time

loosened. Every family group when it breaks up housekeeping in the

spring represents five generations. First, there are the two old

beavers, heads of the family and absolute rulers, who first engineered

the big dam and houses, and have directed repairs for nobody knows how

long. Next in importance are the baby beavers, no bigger than

musquashes, with fur like silk velvet, and eyes always wide open at

the wonders of the first season out; then the one-and two-year-olds,

frisky as boys let loose from school, always in mischief and having to

be looked after, and occasionally nipped; then the three-year-olds,

who presently leave the group and go their separate happy ways in

search of mates. So the long days go by in a kind of careless summer

excursion; and when one sometimes finds their camping ground in his

own summer roving through the wilderness, he looks upon it with

curious sympathy. Fellow campers are they, pitching their tents by

sunny lakes and alder-fringed, trout-haunted brooks, always close to

Nature's heart, and loving the wild, free life much as he does

himself.

But when the days grow short and chill, and the twitter of warblers

gives place to the _honk_ of passing geese, and wild ducks gather in

the lakes, then the heart of the beaver goes back to his home; and

presently he follows his heart. September finds them gathered about

the old dam again, the older heads filled with plans of repair and new

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 best bark are

then cut into short lengths, which are rolled down the bank and

floated to the pool at the dam.

Considerable discussion has taken place as to how the beaver sinks his

wood--for of course he must sink it, else it would freeze into the ice

and be useless. One theory is that the beavers suck the air from each

stick. Two witnesses declare to me they have seen them doing it; and

in a natural history book of my childhood there is a picture of a

beaver with the end of a three-foot stick in his mouth, sucking the

air out. Just as if the beavers didn't know better, even if the absurd

thing were possible! The simplest way is to cut the wood early and

leave it in the water a while, when it sinks of itself; for green

birch and poplar are almost as heavy as water. They soon get

waterlogged and go to the bottom. It is almost impossible for

lumbermen to drive spool wood (birch) for this reason. If the nights

grow suddenly cold before the wood sinks, the beavers take it down to

the bottom and press it slightly into the mud; or else they push

sticks under those that float against the dam, and more under these;

and so on till the stream is full to the bottom, the weight of those

above keeping the others down. Much of the wood is lost in this way by

being frozen into the ice; but the beaver knows that, and cuts

plenty.

When a beaver is hungry in winter he comes down under the ice, selects

a stick, carries it up into his house, and eats the bark. Then he

carries the peeled stick back under the ice and puts it aside out of

the way.

Once, in winter, it occurred to me that soaking spoiled the flavor of

bark, and that the beavers might like a fresh bite. So I cut a hole in

the ice on the pool above their dam. Of course the chopping scared the

beavers; it was vain to experiment that day. I spread a blanket and

some thick boughs over the hole to keep it from freezing over too

thickly, and went away.

Next day I pushed the end of a freshly cut birch pole down among the

beavers' store, lay down with my face to the hole after carefully

cutting out the thin ice, drew a big blanket round my head and the

projecting end of the pole to shut out the light, and watched. For a

while it was all dark as a pocket; then I began to see things dimly.

Presently a darker shadow shot along the bottom and grabbed the pole.

It was a beaver, with a twenty dollar coat on. He tugged; I held on

tight--which surprised him so that he went back into his house to

catch breath.

But the taste of fresh bark was in his mouth, and soon he was back

with another beaver. Both took hold this time and pulled together. No

use! They began to swim round, examining the queer pole on every

side. "What kind of a stick are you, anyway?" one was thinking. "You

didn't grow here, because I would have found you long ago." "And

you're not frozen into the ice," said the other, "because you

wriggle." Then they both took hold again, and I began to haul up

carefully. I wanted to see them nearer. That surprised them immensely;

but I think they would have held on only for an accident. The blanket

slipped away; a stream of light shot in; there were two great whirls

in the water; and that was the end of the experiment. They did not

come back, though I waited till I was almost frozen. But I cut some

fresh birch and pushed it under the ice to pay for my share in the

entertainment.

The beaver's house is generally the last thing attended to. He likes

to build this when the nights grow cold enough to freeze his mortar

soon after it is laid. Two or three tunnels are dug from the bottom of

the beaver pond up through the bank, coming to the surface together at

the point where the center of the house is to be. Around this he lays

solid foundations of log and stone in a circle from six to fifteen

feet in diameter, according to the number of beavers to occupy the

house. On these foundations he rears a thick mass of sticks and grass,

which are held together by plenty of mud. The top is roofed by stout

sticks arranged as in an Indian wigwam, and the whole domed over with

grass, stones, sticks, and mud. Once this is solidly frozen, the

beaver sleeps in peace; his house is burglar proof.

If on a lake shore, where the rise of water is never great, the

beaver's house is four or five feet high. On streams subject to

freshets they may be two or three times that height. As in the case of

the musquash (or muskrat), a strange instinct guides the beaver as to

the height of his dwelling. He builds high or low, according to his

expectations of high or low water; and he is rarely drowned out of his

dry nest.

Sometimes two or three families unite to build a single large house,

but always in such cases each family has its separate apartment. When

a house is dug open it is evident from the different impressions that

each member of the family has his own bed, which he always occupies.

Beavers are exemplary in their neatness; the house after five months'

use is as neat as when first made.

All their building is primarily a matter of instinct, for a tame

beaver builds miniature dams and houses on the floor of his cage.

Still it is not an uncontrollable instinct like that of most birds;

nor blind, like that of rats and squirrels at times. I have found

beaver houses on lake shores where no dam was built, simply because

the water was deep enough, and none was needed. In vacation time the

young beavers build for fun, just as boys build a dam wherever they

can find running water. I am persuaded also (and this may explain some

of the dams that seem stupidly placed) that at times the old beavers

set the young to work in summer, in order that they may know how to

build when it becomes necessary. This is a hard theory to prove, for

the beavers work by night, preferably on dark, rainy nights, when they

are safest on land to gather materials. But while building is

instinctive, skilful building is the result of practice and

experience. And some of the beaver dams show wonderful skill.

[Illustration]

There is one beaver that never builds, that never troubles himself

about house, or dam, or winter's store. I am not sure whether we ought

to call him the genius or the lazy man of the family. The bank beaver

is a solitary old bachelor living in a den, like a mink, in the bank

of a stream. He does not build a house, because a den under a cedar's

roots is as safe and warm. He never builds a dam, because there are

deep places in the river where the current is too swift to freeze. He

finds tender twigs much juicier, even in winter, than stale bark

stored under water. As for his telltale tracks in the snow, his wits

must guard him against enemies; and there is the open stretch of river

to flee to.

There are two theories among Indians and trappers to account for the

bank beaver's eccentricities. The first is that he has failed to find

a mate and leaves the colony, or is driven out, to lead a lonely

bachelor life. His conduct during the mating season certainly favors

this theory, for never was anybody more diligent in his search for a

wife than he. Up and down the streams and alder brooks of a whole wild

countryside he wanders without rest, stopping here and there on a

grassy point to gather a little handful of mud, like a child's mud

pie, all patted smooth, in the midst of which is a little strong

smelling musk. When you find that sign, in a circle of carefully

trimmed grass under the alders, you know that there is a young beaver

on that stream looking for a wife. And when the young beaver finds his

pie opened and closed again, he knows that there is a mate there

somewhere waiting for him. But the poor bank beaver never finds his

mate, and the next winter must go back to his solitary den. He is much

more easily caught than other beavers, and the trappers say it is

because he is lonely and tired of life.

The second theory is that generally held by Indians. They say the bank

beaver is lazy and refuses to work with the others; so they drive him

out. When beavers are busy they are very busy, and tolerate no

loafing. Perhaps he even tries to persuade them that all their work is

unnecessary, and so shares the fate of reformers in general.

While examining the den of a bank beaver last summer another theory

suggested itself. Is not this one of the rare animals in which all the

instincts of his kind are lacking? He does not build because he has no

impulse to build; he does not know how. So he represents what the

beaver was, thousands of years ago, before he learned how to construct

his dam and house, reappearing now by some strange freak of heredity,

and finding himself wofully out of place and time. The other beavers

drive him away because all gregarious animals and birds have a strong

fear and dislike of any irregularity in their kind. Even when the

peculiarity is slight--a wound, or a deformity--they drive the poor

victim from their midst remorselessly. It is a cruel instinct, but

part of one of the oldest in creation, the instinct which preserves

the species. This explains why the bank beaver never finds a mate;

none of the beavers will have anything to do with him.

This occasional lack of instinct is not peculiar to the beavers. Now

and then a bird is hatched here in the North that has no impulse to

migrate. He cries after his departing comrades, but never follows. So

he remains and is lost in the storms of winter.

There are few creatures in the wilderness more difficult to observe

than the beavers, both on account of their extreme shyness and because

they work only by night. The best way to get a glimpse of them at work

is to make a break in their dam and pull the top from one of their

houses some autumn afternoon, at the time of full moon. Just before

twilight you must steal back and hide some distance from the dam. Even

then the chances are against you, for the beavers are suspicious, keen

of ear and nose, and generally refuse to show themselves till after

the moon sets or you have gone away. You may have to break their dam

half a dozen times, and freeze as often, before you see it repaired.

It is a most interesting sight when it comes at last, and well repays

the watching. The water is pouring through a five-foot break in the

dam; the roof of a house is in ruins. You have rubbed yourself all

over with fir boughs, to destroy some of the scent in your clothes,

and hidden yourself in the top of a fallen tree. The twilight goes;

the moon wheels over the eastern spruces, flooding the river with

silver light. Still no sign of life. You are beginning to think of

another disappointment; to think your toes cannot stand the cold

another minute without stamping, which would spoil everything, when a

ripple shoots swiftly across the pool, and a big beaver comes out on

the bank. He sits up a moment, looking, listening; then goes to the

broken house and sits up again, looking it all over, estimating

damages, making plans. There is a commotion in the water; three others

join him--you are warm now.

Meanwhile three or four more are swimming about the dam, surveying the

damage there. One dives to the bottom, but comes up in a moment to

report all safe below. Another is tugging at a thick pole just below

you. Slowly he tows it out in front, balances a moment and lets it

go--_good!_--squarely across the break. Two others are cutting alders

above; and here come the bushes floating down. Over at the damaged

house two beavers are up on the walls, raising the rafters into place;

a third appears to be laying on the outer covering and plastering it

with mud. Now and then one sits up straight like a rabbit, listens,

stretches his back to get the kinks out, then drops to his work again.

It is brighter now; moon and stars are glimmering in the pool. At the

dam the sound of falling water grows faint as the break is rapidly

closed. The houses loom larger. Over the dome of the one broken, the

dark outline of a beaver passes triumphantly. Quick work that. You

grow more interested; you stretch your neck to see--_splash_! A beaver

gliding past has seen you. As he dives he gives the water a sharp blow

with his broad tail, the danger signal of the beavers, and a startling

one in the dead stillness. There is a sound as of a stick being

plunged end first into the water; a few eddies go running about the

pool, breaking up the moon's reflection; then silence again, and the

lap of ripples on the shore.

You can go home now; you will see nothing more to-night. There's a

beaver over under the other bank, in the shadow where you cannot see

him, just his eyes and ears above water, watching you. He will not

stir; nor will another beaver come out till you go away. As you find

your canoe and paddle back to camp, a ripple made by a beaver's nose

follows silently in the shadow of the alders. At the bend of the river

where you disappear, the ripple halts a while, like a projecting stub

in the current, then turns and goes swiftly back. There is another

splash; the builders come out again; a dozen ripples are scattering

star reflections all over the pool; while the little wood folk pause a

moment to look at the new works curiously, then go their ways, shy,

silent, industrious, through the wilderness night.

Ways of wood folk · 第 15 / 25 题