"Don't black bears sleep through the winter?" questioned the writer of
an attendant who was dealing out mid-day rations of bread and milk at
the park.
"That's the general impression," was the rejoinder, "but we have never
noticed any attempts at hibernation here. Bears are unusually lively
during the cold months, and demand their food as regularly as do the
lions and other feline animals. I don't know that any observations of
value on this question have ever been made on animals in confinement.
I have had some experience with outside animals, and a great many go
through what is called a winter's sleep; and in warm countries there is
what might be called a summer sleep. Bears begin in the fall to look out
for a soft nest; and if it's possible for them to eat more at one time
than another they do it then, and when the cold weather sets in they
are fat and in prime condition. According to some authorities, the fat
produces the carbon that in some way tends to induce somnolency. The
stomach of a bear at this time becomes empty, and naturally shrivels
or draws into a very small space, and is rendered totally useless by
a substance called 'tappen' that clogs it and the intestines; this is
formed of pine leaves and other material that the animal takes from
ants' nest and the trunks of trees in its search after honey. They lie
asleep in this condition for about six months, generally snowed in; but
you can tell the place, as the heat of the bear, what there is left,
keeps an air hole up through the snow. The bear seems to live on its
fat, the tappen preventing its too rapid consumption; and if you run
across them during this time--even along in March just before they wake
up--they are about as fat as when they went in. I have taken a slice of
fat from a black bear six inches thick--regular blubber. I remember,"
continued the man, "one winter I was 'log hauling' in the western part
of this State. We had our eyes on a big tree, and one morning when it
was about ten degrees below zero I tackled it to warm up. I hammered
away for about five hours at it and finally started her, and over she
came--slowly at first, and then as if she was going right through. The
snow was nearly three feet deep, and as the tree struck it flew up for
about twenty feet and half blinded me, and when I came to there was the
biggest black bear I ever saw standing along side of me, looking about
as mixed as I did. I had lost my ax, and the first move I made she
started, and on taking a look I found that she had a nest in the trunk
and had probably turned in for the winter. It was about twenty feet from
the ground, and was built with moss, leaves, and all kinds of truck, and
as warm and as snug as you please--a good place to spend a winter in."
The brown and polar bears have the same habit of lying up for the
winter. An Esquimau informed Captain Lyon that in the first of the
winter the pregnant bears are always fat and solitary. When a heavy fall
of snow sets in the animal seeks some hollow place in which she can lie
down, and remains quiet while the snow covers her. Sometimes she will
wait until a quantity of snow has fallen and then digs herself a cave;
at all events it seems necessary that she should be covered up by the
snow. She now goes to sleep and does not wake until the spring sun is
pretty high, when she brings forth two cubs. The cave by this time has
become much larger by the effect of the animal's warmth and breath, so
that the cubs have room enough to move, and they acquire considerable
strength by continually sucking. The dam at length becomes so thin and
weak that it is with great difficulty she extricates herself, which she
does when the sun is powerful enough to throw a strong glare through
the snow which roofs the den. Then the family comes out, and will take
anything that comes along in the way of food. During the long sleep
the temperature of the bear's blood is reduced to almost that of
the surrounding air. The power of will over the muscles seems to be
suspended, respiration is hardly noticeable, and most of the vital
functions are at a complete standstill--the entire body sleeping, as it
were. The male grizzly bear never hibernates. The young and the females,
however, build nests, one of which measured ten feet high, five feet
long, and six feet wide.
Bats are great winter sleepers, and in most of the known caves they can
be found during the cold months clinging to the walls and to each other.
During hibernation their respiration ceases almost entirely, and only
the most careful use of a stethoscope can reveal it. The air that has
surrounded numbers of them has been carefully examined and not the
slightest evidence found of its having been breathed; and, stranger yet,
they can exist in this condition in gas, that, were they awake, would
prove instantly fatal. A machine has been invented to examine these and
other animals while in this condition. A delicate index records the
slightest pulsation, while a thermometer shows the rise and fall of the
temperature at every moment during the period; and by an arrangement
of the wing, the circulation of the blood is recorded. A more delicate
experiment can hardly be imagined, as a strong breath, a sneeze, or a
footfall will cause the subject of the experiment to recover enough to
respire several times; and the effect of this on the machine can be
imagined when it is known that though, while in this condition, they
produce no effect upon the oxygen of the air about them, they consume
when respiring more than four cubic inches of oxygen an hour.
The common marmot is a great underground sleeper. They build large
storehouses, sometimes eight feet in diameter, and from the latter part
of September to April they lie in them, and, like the bears, give birth
to their young during this period.
The dormouse is a remarkable sleeper. Even in their ordinary sleep they
can be taken from the nest and handled without waking them. Toward
winter they acquire a great deal of fat, and stow away a vast amount of
provision around about their nest, and then go to sleep within; but they
rarely awake to use this food unless a very warm period comes around
before the regular breaking up of cold weather.
The hedgehog is a sound winter sleeper, and has been the subject of
an infinite number of experiments while in this condition. One
experimentalist, believing that cold was the cause of their curious
condition, surrounded one with a freezing mixture, and froze it
to death. By increasing the cold about another that was already
hibernating, it was made to wake up; and walked off.
If an animal is suddenly decapitated while in this hibernating
condition, the action of the heart is not affected for some time, a
second life seeming to outlive the one taken. An experiment has been
made in which the brain of the sleeper was removed, then the entire
spinal cord, but for two hours hardly any change was noticeable upon the
action of the heart; and a day after that organ contracted when touched
by the operator.
The writer has the winter nest of a family of ants. A piece of fence
rail was found beneath an old pile of boards and brought into a warm
room for the sake of a rich fungus growing upon it, and several hours
after the table and chairs were found to be covered with ants. Where
they came from was a mystery, until the old rail was accidentally jarred
and a number fell from it. A section was cut down through it, and the
winter home of the tribe destroyed--probably the work of weeks, perhaps
months. The interior of the wood was completely riddled by tunnels and
passages, some being large and holding several hundred ants, while
others contained only a few. In some of the interior passages the ants
had not been affected by the heat, and were packed in great masses and
evidently fast asleep; they soon recovered, however, and walked off
slowly in different directions, as if wondering if an earthquake or
spring had come.
A great number of insects go through a period of hibernation, especially
spiders. The young of the latter are often covered by the parent; first,
by coarse strings of silk, as if to hold them in place, and then by
a white, silvery web worked over them, which forms probably a sure
protection from wind and weather.
The writer has a cherry-stone in which is coiled up an insect, best
known as the sowbug. A squirrel had probably eaten out the meat and
opened the way, and in this snug retreat we found the little hibernater
snugly rolled up, as is also its habit when alarmed. The mouth of the
hole was stopped by black soil, but whether from accident or by the
animal itself we could not tell.
Some fishes and reptiles are hibernaters. Frogs and toads sleep out the
winter at the bottom of ponds or in holes in the ground. Tree toads, if
kept in a cage in the winter and provided with soil, will endeavor to
cover themselves with it, showing how strong the instinct or habit
is. Some fishes are so insensible to heat or cold that when in this
condition they can be frozen and carried for a number of days and then
be brought back to an active condition. The pond snail passes into a
winter sleep as soon as the temperature of the water is below 14° Cent.,
that is, they will not digest food or grow until the temperature of the
water is at least up to 15° Cent. Those who have watched the Harlem
River from McComb's Dam Bridge cannot have failed to notice the curious
appearance of the muddy shores of the river and creeks at low tide.
If the sun shines brightly, the dismal beach seems to quiver and
scintillate in a most beautiful manner, reflecting the light like so
many diamonds. If we draw nearer, this shore is seen to be entirely
covered in places with little snails, that, left by the tide, are
forging through the mud to regain the water, and the sunlight striking
on them is reflected by the glass-like secretion with which they are
covered, producing the curious effect noticed. This could be seen in the
warm months, but now, not a snail of the countless millions can be seen.
They have gone down in search of "hard-pan," there to hibernate until
next April. The land snail (_Helix pomatia_) sleeps four months during
the year, and does not throw off the calcareous lid that protects it
during this time until the day temperature has reached 12° Cent. Prairie
dogs feel the effect of temperature as low as this.
In Cuba reptiles hibernate between 7° and 24° Cent., according to the
species. In warmer countries, snakes, lizards, frogs, etc., fall into a
state called chill coma that precisely resembles winter sleep, but their
temperature is far above that at which hibernating animals of the north
are still active. The state of hibernation is not the direct result of
an extreme of heat or cold, but rather is caused by a departure from the
optimum. In the snail its normal temperature is about the same as the
water, and being a poor heat producer it is not surprising that when
the water grows colder the animal is forced to succumb; but it is
a remarkable fact that warm-blooded animals like many of the
above-mentioned, whose bodies are maintained by internal processes at a
high temperature of 26° to 38°, are incapable of resisting the lowering
influence of cold. The fall in temperature in some is wonderful; as an
example, the high body temperature of warm-blooded animals may be said
to oscillate between 36° and 43° Cent. (this includes man). Experiments
made with the zizel show that during hibernation this animal's
temperature is only 2° Cent., the lowest known; and a thermometer
introduced into the animal indicated the same, showing that warm-blooded
animals in hibernating become truly cold blooded animals. If a rabbit's
temperature reaches 15° Cent., it will die. The germs of bryozoa or of
the fresh water sponges resist any amount of cold, but the full grown
forms die at the first cold turn. Insects are destroyed, but their eggs
live, though of the greatest possible delicacy. Salmon eggs have been
carried from this State to Australia, and there hatched. In fact, some
animals live in the ice, as the glacier flea and several others.
As it is not the direct result of extremes of heat or cold that produces
sleep, neither is the awakening from hibernation directly caused by
a rise of temperature. In experiments made upon weasels, which are
sometimes caught asleep, one came to life in about three hours, during
which the temperature of the room remained the same as it had been
during the entire hibernation, viz., 10° Cent. In another weasel, during
the awakening, the body temperature rose very rapidly--and more so in
the second part of the period than in the first. In the first hour and
fifty-five minutes of the awakening the body temperature rose 6.6° Cent,
and in the following fifty minutes it rose 17° Cent. This remarkable
increase took place without any vigorous movements on the part of the
weasel. Even its breathing showed no increase in proportion to the rise.
These cases show that though, at certain seasons, animals relax as it
were and lie dormant, and recover, seemingly at the will of the weather,
yet, in point of fact, the rise and fall of temperature has no direct
effect upon them. The cause is an internal one, awaiting discovery.--C.
F. HOLDER, in _Forest and Stream_.
* * * * *
What is described as the largest steel sailing ship afloat was lately
launched at Belfast, Ireland. It registers 2,220 tons, and has been
named the Garfield. It will be employed in the Australian and California
trade.
* * * * *