FAMINE IN BEAVER-LAND
Cold weather came one fall before my new beaver neighbours had laid in
their winter’s food. They had harvested one food supply several miles
down stream but a fierce forest fire had devastated the region while
they were in the midst of their preparations for winter and left their
home site unliveable. The beavers in a body started off to found a new
colony, having the hardships and adventures that ever fall to
pioneers.
The place selected for their new home was on a tributary stream not
far from my cabin. Here they built a typical house of sticks, sod, and
mud. The stream ran through an old glacier meadow partly overgrown
with forest. One side carried a belt of pines. Beyond the pines was a
ragged and extensive growth of quaking aspen. Up stream the mountain
rose steeply to the summit of Mt. Meeker.
While the beavers were working on a dam which was to give them ample
water in the pond to prevent its freezing to the bottom, a trapper
came into the region. He lingered and broke and rebroke the dam three
or four times. When he finally left, autumn was half gone and
preparations for winter in the new colony were only well begun. The
dam was still low and uncompleted. As yet they had not begun cutting
and storing aspen for their winter’s food supply.
These beavers had been industrious. They had planned well. But it was
a case of one misfortune quickly following another. A severe cold wave
still further and seriously handicapped the harvest gathering of the
colonists. The quieter reaches of the stream were frozen over and a
heavy plating of ice was left on the pond. They would have difficulty
transporting their food-cut aspens under such conditions.
Winter supplies for this colony--green aspen or birch trees--must be
had. Ordinarily, beavers cut the trees most easily obtained: first
those on the shore of the pond, then those up stream, and finally
those on near-by, down-hill slopes. Rarely does a beaver go fifty feet
from the water. But if necessary he will go down stream and float
trees against the current, or drag trees up steep slopes. This pond
did not have, as is common, a border of aspen trees.
Late October I visited this new wilderness home. In the lower end of
the frozen pond was a two-foot hole in the ice. This had been gnawed
by the beavers, but for what purpose I could not then imagine.
One crew of loggers had started to work in a grove about two hundred
feet from the hole in the ice. They were cutting aspens that were
about four inches in diameter and twelve feet high. But before
dragging them to the pond an opening or trailway through the woods had
been cleared. Every bush in the way was cut off, every obstructing log
cut in two and the ends rolled aside.
Dragging their tree cuttings to the pond was slow, hard work, and it
was also dangerous work for a slow-moving beaver to go so far from the
water. A beaver is heavy bodied and short-legged. With webbed hind
feet he is a speedy swimmer, but on land he is a lubber and moves
slowly and with effort.
A few days later the purpose of the hole in the ice of the frozen pond
was made plain. A freshly swept trail in the snow led to it out of the
woods. The beavers were taking their green aspen cuttings through the
hole into the pond for their winter’s food. They had begun storing
winter food at last.
I followed the trail back to where a number of aspens had been cut.
Their stumps were about fifteen inches above the snow. Two trees still
lay where they fell. These were about six inches in diameter and
perhaps twenty feet long. Preparatory to being dragged to the pond
they had been gnawed into sections of from three to six feet.
The beavers had not nearly finished their harvesting when a heavy fall
of snow came and they were compelled to abandon their carefully made
dragway and the aspen grove where they had been cutting. The nearest
aspens now available were only sixty feet from the edge of the pond.
But a thick belt of pines and a confusion of large, fallen,
fire-killed spruce logs lay between the pond and this aspen grove.
Deep snow, thick pines, and fallen logs did not stop their
harvest-gathering efforts. Tracks in the snow showed that they went to
work beyond the belt of pines. During one night five beavers had
wallowed out to the aspens, felled several and dragged them into the
pond. But wolves appeared to realize the distress of the beavers. They
lurked about for opportunities to seize these hunger-driven animals.
While harvesting the aspen grove wolves had pounced upon one of the
beavers at work and another on his way to the pond had been pursued,
overtaken, and killed in the deep snow.
During three days of good weather which followed, ever watchful for
wolves, the beavers cut few aspens. Then came another snowstorm. The
work of harvesting winter supplies was still further hindered.
But beavers never give up. To obtain aspens which were to supply them
with winter food they finally dug a tunnel. They began this on the
bottom of the pond near the shore and dug outward toward the aspen
grove. The tunnel was about two feet under the surface for fifteen
feet. From this point it inclined upward and came out under a pine
tree, close to the aspens. In only the last few feet, where the
digging was through frozen ground, was there difficult digging of this
tunnel. Apparently the thick carpet of fallen leaves and the deep snow
checked the frost and the earth had not frozen deeply.
From the end of this tunnel the beavers cleared a dragway about
eighteen inches wide to the aspen grove. In doing this they cut
through three or four large logs and tunnelled under a number of
others. Then aspens were felled, cut in short sections, dragged to the
end of the tunnel, pushed through this out into the pond beneath the
ice, and finally piled on the bottom of the pond close to the house.
Solid snowdrifts formed in the grove while this slow work of
transportation was going on. A few aspens were cut from the top of a
five-foot snowdrift. The following summer these stumps suggested that
prehistoric beavers--large as bears--had reappeared on earth.
At last cold, ice, snow, and enemies completely stopped the beavers’
harvest gathering. The food provided for the colony’s winter supply
was less than one half that needed. But the beavers had done their
best, and come what may, they would alertly, stoically meet it.
These colonists had a hard winter. I visited them a number of times.
Now and then snow covered the frozen pond, but usually the wind in
sweeping down the open-stream avenue through the woods left the ice
clear. One day, looking through the clear ice of the pond, I counted
six beavers, but on most occasions I was able to see only one or two.
The population of this colony probably numbered twelve or fifteen.
The upper part of the area flooded by their pond had been a
semi-swampy tract bearing thick growths of water-loving plants. The
roots of sedge, bulbs of lilies, tubers of many plants, and long juicy
roots of willow and alder were made use of by these beavers facing a
food-shortage.
I supposed it was only a question of time before they would be shut
off by the thick ice from this root supply. But they dug a deep
waterway--a canal about two feet wide and nearly as deep--from the
house in the centre of the pond to the heart of the rooty area. Even
after most of the pond was frozen to the bottom they had an open line
of communication with the root supplies.
Mutual aid is a factor in beaver life. I do not know how many days’
work this ditch required; but when one of the beavers in a colony
work, all work. Since late summer these beavers had worked at one task
after another; they had unitedly worked for the welfare of each member
of the colony. With mutual aid beaver colonists achieve much in a
short time. Their strong love for home, causing them to remain long in
one place, and the peculiar work which this calls for, makes changes
on earth sometimes enduring for centuries.
But they had only commenced to dig out the roots on the bottom of the
pond when the ever-thickening ice froze over this life-saving food
supply. The water would have been deeper over this area but the
beavers’ early hard luck had prevented their building the dam as high
as it should have been.
I do not know how they handled the food-shortage, whether or not they
went on short rations. But no beaver had more than his portion, for
beavers are coöperators, they work in common, and so long as the food
supply lasts each has his share.
I had glimpses of the beavers’ eager digging through the clear spots
in the ice. They tore the root-filled section to pieces and devoured
all that it contained. But not until the following summer, when the
broken dam released the water, did I realize how deeply and completely
the bottom of the pond had been stirred and ploughed. I have seen
gardens uprooted by hogs, and mountain meadows dug to pieces by
grizzly bears, but neither of them equalled this.
The supply of roots ran out and the bark of the green aspens was eaten
off, and still this mountain region was white with winter and the pond
locked and sealed with ice. Beavers are strict vegetarians. There were
trout in the pond, but these were not caught; nor were the bodies of
the starved ones eaten, as sometimes occurs among other animals. The
beavers must escape from their now foodless prison or perish.
Spring examinations which I made indicated that they had tried to
escape through the long tunnel which had been made to obtain the
aspens, but this had nearly filled with ice. They had then driven
several feet of a new tunnel, but evidently found they could not
accomplish it through the frozen, gravelly earth. Beavers are
engineers--the handling of earth in building dams or in the making of
canals is as much in their line as tree felling--but cutting and
tunnelling through gravelly, frozen earth is near impossible for
them.
They then attempted to cut a hole upward through the two feet of ice,
as I found out later when the ice was breaking up. And they had almost
succeeded. On the edge of their house they had raised a working
foundation of mud and sticks and gnawed upward to within three or four
inches of the surface. Beavers are expert gnawers and have been known
with their powerful teeth and strong jaws to gnaw off and fell trees
more than two feet in diameter. Perhaps they might have succeeded
eventually, but they apparently found another and better way out of
the pond.
What they finally did was to tunnel out through the unfrozen earth
beneath the bottom of the dam. They had commenced on the bottom of the
pond and driven a fifteen-inch tunnel nearly level through the base of
the dam, and a foot or two beneath the water and below frostline. This
came out in the ice-covered stream channel, beneath the frozen earth.
As this tunnel had to be dug under water, it must have been slow work
and to have constantly called for relay efforts. When a working beaver
had to breathe it was necessary for him to swim to the house and climb
up to the floor, above water level, in order to obtain air.
Tracks of six muddy-footed fellows on the snow at the outer end of the
successful tunnel told the number who survived the winter’s
food-shortage. Spring came, and warmth and flood water broke up the
ice on the pond about a month after they escaped. No young beavers
were seen. These surviving beavers lived in bank holes along the
stream until summer. Then they wandered away. Late that August they,
or six other beavers, came to the place. They completed the dam and
repaired the house, and by mid-October had a huge pile of food stored
in the pond for the winter.