THE BIOLOGY OF WINTER
ARGUMENT.—I. An appreciation of the full biological import of Winter
is not altogether easy for us, here and now. We must think of peoples with
less artificial environment, of more wintry regions, and of Glacial Epochs.
II. The Sagas of the Biology of Winter are to be found in such stories as
those of the Sleeping Beauty and Balder. III. The astronomical facts bear
out our vaguer impressions. IV. Reactions to the cold and scarcity of
Winter are very variable:—flight, concealment, colour-change, and so on.
V. Hibernation in its varying degrees is a common solution. VI. Yet to
many death is inevitable. Winter is the time of intensest elimination. This
affects not only individuals, but races. The tree of life grows, but it is also
pruned. The only biological consolation is that the fruition of the tree has
improved.
I
A TRUE judgment as to the biological import of a
Northern Winter is not altogether easy for us,
here and now. It is not easy for us, who are
cunning and far-sighted, clothed and fire-making
organisms; it is not easy here, for, in spite of our
grumbling, a British Winter is usually a mild
affair; it is not altogether easy now, for our worst winters are but
far-off echoes of the Glacial Epoch, when Winter not only con-
quered Summer, but remained victorious for Ages. Thus it is
evident that to do Winter justice we have need to question the
Lapps and Samoyedes and other dwellers in the Far North,
or, where they have not voices, explorers like Nansen and
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Peary; we must think of the Polar Regions, of Alpine life
above the snow-line, or of that dark, silent, plantless, intensely
cold world—the Deep Sea—where the spell of Winter is un-
relieved and perennial; and we must let our imagination travel
back to the Ice Ages—the Ages of Horror—during which
whole faunas shuddered. Unless we make some such efforts,
which we can only now suggest, we are likely to estimate the
power of Winter too lightly, and fail in seeing to what degree
it casts a spell, often a fatal one, upon life.
II
A true appreciation of Winter was long since expressed in the
story of the Sleeping Beauty. She was richly dowered, we
remember, with vigorous beauty and joyous grace, but all her
gifts were shadowed by the foreboded doom of early death.
Yet by a friendly fairy in reserve, to wit, the residual beneficence
of Nature, the doom was transmuted into a kinder spell, which
bound her to sleep but not to dying. All care notwithstanding,
the spindle pierced her hand, she fell into deep sleep, whence
at last the Prince’s kiss served for her awakening. Various
commentators apart, the meaning seems plain: the Princess
was our fair earth with all its glow of life, her youth was
Summer—often shadowed—the fatal spindle was the piercing
cold, the spell-bound sleep was Winter’s long rest, the kiss that
awakened was the first strong sunshine of Spring. The beauti-
ful old story is literally one of the ‘fairy-tales of Science.’
In the same way, though there is doubtless much else in
the myth, we can have no doubt that Balder the Beautiful
represented the virility and vitality of the sunny Summer, and
that the twig of gloom, the Mistletoe, which flourishes and
fruits in Winter, was the emblem of the freezing cold which so
oftefi brings sudden death or the quiet peace of sleep. A
similar interpretation holds for the not less subtle allegory of
Proserpina.
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III
But let us turn from fancy to fact! The astronomers tell us of
the general law that on either hemisphere 63 per cent, of the
total heat of the year is received during Summer, and 37 per
cent, in “Winter; but we feel that this statement, fundamental as
it is, hardly expresses the full force of the case. First of all,
the astronomers are thinking, and, from their point of view,
rightly, of a year with only two seasons; therefore, as we are
dealing with four, we must refer part of the 37 per cent, received
in Winter to late Autumn and part to early Spring, leaving
Winter poor indeed. The same authorities also tell us that the
length of Summer and Winter is variable; thus we have now 186
days of Summer, and 179 days of Winter (in the two-season
sense), while it is but a geological yesterday since in the Ice
Ages the Summer lasted for only 166 days, while 199 lay in the
grasp of Winter. This is again very important, for the total
amount of warmth received has obviously to be divided by the
number of days in the season, to give us a numerical expression
of the mean daily sun-heat at any given time. Yet finally, this
must not hide from us the commonplace of experience that it
is not the average temperature which, so to speak, says yea or
nay to this or that form of life ; it is rather the occurrence of
certain maxima and minima, a terrible heat-wave or a week of
fatally frosty nights.
IV
To the cold and scarcity of food which Winter involves in this
and more northerly latitudes, there is great variety of reaction
on the part of organisms. Of this variety we can only give a
few illustrations. Thus most of our birds, emblems of freedom,
escape the spell by flight, and, though death is often fleeter
still and overtakes them by the way, there can be no doubt
that the migration-solution is an effective one. Among those
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who are hardy enough, or foolhardy enough, to remain with us,
the rate of mortality is often disastrously high.
Other creatures, unequal to the long and adventurous journeys
of the birds, retire into winter-quarters, in which they lie low,
awaiting happier days. Thus the earthworms burrow more
deeply than ever, the lemmings tunnel their winding ways be-
neath the icy crust of the Tundra, the pupae and cocoons of
insects lie inert in sheltered corners, the frogs bury themselves
deeply in the mud, and the slow-worms coil up together in the
penetralia of their retreats.
Others, again, such as the Arctic fox, the mountain hare, the
ermine, the Hudson’s Bay lemming, and the ptarmigan, face
the dread enchantment, but turn paler and paler under the
spell, until they are white as the snow itself—a safety-giving
pallor. It seems likely that a seasonal colour-change of this
nature is, in the formal language of the schools, a modification,
induced by the cold, but superposed upon a constitutional
variation or hereditary predisposition to change. Thus it is
well known of Arctic fox and mountain hare, for instance, that
the degree of whiteness varies from year to year with the
intensity of the Winter. As for its utility, this is at least
twofold—the white dress is of service alike in the chase and in
flight, while on the other hand it is the warmest dress when
the external temperature is less than that of the body.
Man, himself, gets inside other creatures’ skins, and bids
defiance to weather, or, having in his cunning tapped one of
the earth’s great stores of energy, sits by the hearth gloating
in the warmth of a larger sun than that which now sends him
too little cheer. His indifference is, however, in part artificial,
as a prolonged coal-strike shows; in part, a privilege of the
few, as a glance at the tattered and torn suffices to prove; and
in part, merely local, as a short journey northwards convinces
us; and he, too, like the birds, often migrates even from our
British mildness to a sunnier South, and knows, like many
a beast, of winter-refuges, whether in Scottish poor-house or
Mentone ‘pension.’
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V
To many organisms, both of high and low degree, the alterna-
tive comes,—to sleep or die. The spindle cannot be escaped,
the cold shall pierce like a sword:—but sleep! and it may be
well. Of this sleep there are indeed many degrees, from the
mysterious latent-life of frozen seeds and animal germs, to the
almost equally mysterious true hibernation of marmot and
hedgehog. Often, too, it must be confessed that what began
in slumber ends by becoming sleep’s twin-sister, Death. Yet,
we understand so little of any of these more or less dormant
states in their relations to one another, or, indeed, of any one
by itself, that we may avoid an analysis which would be in-
appropriate here, and think of Winter as the sleep-bringer.
The great hypnotist lifts his hands, and the sap stands still in
the tree, and the song is hushed in the bird’s throat; he makes
his passes, and growth ceases in bud and seed, in cocoon and
egg; he breathes, and sleep falls upon marmot, hamster, and
hedgehog, upon tortoise, frog, and fish, upon snail and insect;
he commands—his voice is the North Wind,—and the water
stands in the running brooks, and the very waves of the fiord
are still. Even in our own mild country, is not the freezing of
Loch Fyne upon record?
Apart from the state of latent life—in which a paste-eel, for
instance, may lie neither living nor dead for fourteen long years,
and seeds for many decennia—there is no form of sleep so near
to death as this to which the Wizard of the North commands
the true hibernators. Somnolence penetrates to the deep
recesses of the creature’s being, as the histologist well knows,
who tells us of the minute structural changes observed in the
cellular elements of the sleeping hedgehog.
The heart beats feebly and intermittently, breathing is at long
intervals and very sluggish, the food-canal is empty, income is
almost at zero, and expenditure but little more. The sleeper
may be immersed in water for twenty minutes, or subjected
without apparent result to noxious gases. The fat, accumulated
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in days of plenty, is slowly burnt away, sustaining in some
measure the animal heat. Yet temperature falls very markedly,
to a degree which in ordinary life would be fatal; irritability
wanes to a minimum; the ordinary reflexes are at most faint;
and the creature steadily loses weight. The wonder is that it
keeps alive.
The slumberers differ much in the soundness of their sleep. Thus
there are light sleepers, like the dormouse, the harvest mouse,
and the squirrel; and heavy sleepers, like hedgehog, hamster,
and marmot, or like the tortoise, whom the crack of doom
would scarce disturb. Quaint is the somnolence of the mother
polar bear, who, after awaking in her snowy couch to give birth
to her two cubs, sets them a-sucking, yawns, and falls asleep
again. But she, and even the seven sleepers, must yield to the
snail who overslept himself so far that when he awoke it was
in a case in the British Museum wherein he bore a ticket already
many years old. There was another Rip van Winkle snail who
awoke to find himself an extinct species, but that, as they
say, is another story!’
After we allow for the tendency cold has to produce coma, of
which Alpine travellers have told us tales; for the drowsiness
which is said—let us hope it is true—to take the edge off starva-
tion ; for the sleepiness induced, e.g., in church or lecture-room
by confined atmosphere, of which no proof is required, there
seems to be need of further physiological explanation. It has
been suggested, and wisely it seems to us, that the retention
of waste-products induces a state of ‘auto-intoxication’—a
drugging or poisoning of the system with its own excretions,
a banking-up of the fire of life with its own ashes. It seems
plausible that this will tend to keep the sleepy sleeping, and
the idea maybe hazarded that one of the reasons why plants
are not more wide awake is just this retention of nitrogenous
waste-products. For it is well known that plants do not get
rid of these. The same is in a measure true of the sea-squirts
or Ascidians, which in their adult life are notoriously plant-like
and sleepy animals.
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The general import of hibernation is in most cases plain. Life
saves itself by ceasing to struggle, by retiring within its en-
trenchments. Death is baffled by a device in which activity
virtually ceases without life itself being surrendered. Yet
there are other aspects of the Winter’s sleep. To some it is a
time of repair—a long night—after the nervous fatigue of a
longer day. Thus, it is not difficult to understand that, quite
apart from the weather, it is good that the queen humble-bee
should sleep through the Winter, just as it is well for the fisher-
man that he should weep after the storm. In short, we return
to our main thesis, that life is rhythmic, and that the seasons
punctuate it.
To others the sleep is in some measure a preparation for a new
day. Thus in the seeds which slumber in the earth, each a
young life, there is a rotting away of the husks which the
delicate embryo could scarce burst, and later on there are pro-
cesses of fermentation, by which the legacy of hard, condensed
food is made available for the young plant. That it is not
merely the unpropitious weather and the hard soil which
make it necessary for the seeds to sleep may be proved by
experiment, and is also shown by the fact that not a few
normally lie dormant for several years. Similarly, within the
cocoons there lie the chrysalids, quaintly mummy-like and
inert to all appearance, but slowly undergoing that marvellous
transformation, the result of which is the winged butterfly—the
Psyche.
VI
It seems a true paradox that one of the great facts in the
Biology of Winter is the Frequency of Death. Not that there
is any season when Death is not busy, or any opportunity which
he does not seize; he winnows among the newborn weaklings
of the early Spring, he lays pitfalls for the adolescent, he thins
the ranks of Summer’s industry, he puts in a full stop at the
limit of growth, he forces open the door which love seeks to
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keep closed, he harvests in Autumn; but it is in Winter that
his power is most felt. It is the time of the least heat, least
light, least food; and life hurries on the downgrade to death.
The influence on plant-life is most obvious and direct; a large
fraction of the income of radiant energy is cut off, the water-
supply is also reduced, and there is further risk that the frost
cause bursting of cells and vessels within the plant just as in
our houses. The diminished vigour of plant-life means less
food for the animals, and on them too the relative lack of
warmth and light has a directly disastrous effect. Given
‘A winter such as when birds die
In the deep forests, and the fishes lie
Stiffened in the translucent ice, which makes
Even the mud and slime of the warm lakes
A wrinkled clod, as hard as brick,’
the decimating influences are perceptible on every side. Thus
of the mortality during the hard winter 1894-95 we have eloquent
statistical evidence from moor and forest lake and seashore.
Winter is indeed a time of rest and sleep, but as truly of
elimination and death.
Death always means the irrecoverable cessation of bodily life,
but it has so many forms—violent, bacterial, and natural,—each,
again, with its subdivisions, that we cannot without inquiry say
for any particular case that the rate of mortality is greatest in
Winter. Yet the general induction appears safe that in our
latitude Winter is the time of severest elimination. Thus the
season which is apt to seem dull to the field-naturalist is full of
interest to the evolutionist. The hedgerows are bare, and the
woods silent, the pools are clear and apparently devoid of life,
the shore is comparatively barren, even the sea has lost much
of its wonted abundance. And, though much of this scarcity is
only apparent—life lying low, or asleep, or on a journey—we
must allow that it is often altogether sped. Proserpina has
gone down to Hades. Balder is dead. We have, in short, to
face the inexorable process of natural selection, whereby the
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relatively less fit to the conditions of their life tend to be elimi-
nated, i.e. tend to die before the normal time, and to leave
behind them less than the normal number of offspring. Winter
is the time when the tree of life is most rigorously pruned.
In our study of the decadence of Autumn, we spoke of the
death of individuals and of the consolation which is offered in
the persistence of the race, but we cannot think long over such
matters without recognising that the race itself may perish.
We need only reverse the hands of the geological clock a few
seconds to be convinced of this. We need only go back to the
more recent ice-ages—the ages of Winter’s tyranny—which are
not long past, as time goes. Indeed, we need not leave human
or even modern history at all to find sadly abundant illustra-
tion of lost races.
Keeping, however, to recent animal history, where are the
bears who had their dens in Athole, or the wild boars of the
great Caledonian forest, or the busy beavers who cut their logs
in the Pass of Killicrankie, or the white bulls who wallowed in
the dark waters of the hidden tarns, or the wolves with which
Wales paid her tax to King Edgar?
Or, again, where are the early companions and rivals of our
forefathers in Britain—the cave-lion, the cave-bear, the cave-
hysena, the shaggy mammoth, and the woolly rhinoceros?
Do we know of them at all except in so far as our inheritance
includes some of that hardihood, wisdom, and gentleness which
they and others helped to work out in man?
Or, going much further back, where are the delicately beautiful
graptolites, the quaint trilobites, the great sea-scorpions, the
ancient heavily-armoured fishes, the giant amphibians, the
monstrous reptiles, the dragons, the toothed birds, the old-
fashioned mammals? The most powerful, the most fertile have
not been spared, even those which seem as though they had
been built not for years but for eternity, have wholly passed
away. This is no mere case of leaves falling from off the tree,
it is a lopping of branches.
For some of these lost races, competition was doubtless too
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keen—they outlived their prosperity and went to the wall; for
others the force of changing circumstances was too strong—
they were not plastic enough to change; for others, perhaps,
over-specialisation or feverish activity was fatal; for others it
may be that their constitution was at fault, and that they went
down to destruction, as Lucretius finely phrased it, ‘hampered
all in their own death-bringing shackles.’ We cannot console
ourselves with any vague notion that such disappearance is a
misnomer for transmutation into some nobler form; that may
be true of certain species, but it is not true of the wholly
extinct races. Nor is there consolation in the notion that the
atoms which were once wrapped up in that whilom bundle of
life known as the Ichthyosaurus may now be part and parcel
of us; for we feel that those particular combinations which we
have called lost races—those smiles of creative genius,—have
gone, gone as utterly as the snows of yester year.
Thus from the elimination now observable around us in this
wintry season our thoughts naturally pass to the great world-
wide process, continuous since life began, which embraces us
also in its inexorable sifting. It does not indeed explain us,
nor the organisms we know, any more than the pruning-hook
explains the tree; but given life and growth, we cannot under-
stand their history apart from elimination. In short, we need
our Winter to explain our Summer, and this perhaps is the only
consolation which the biologist can suggest to the discontented
—that the history of the world as a whole is the history of
a progressive development. The fruition of the tree im-
proves. Perhaps the impersonality of this consolation is
the reason why he who was a very Gallio in Summer
becomes a religious man in Winter.
J. ARTHUR THOMSON.
MLA citation:
Thomson, J. Arthur. “The Biology of Winter.” The Evergreen; A Northern Seasonal, vol. 4, Winter 1896-7, pp. 8-17. Evergreen Digital Edition, edited by Lorraine Janzen Kooistra, 2016-2018. Yellow Nineties 2.0, Ryerson University Centre for Digital Humanities, 2019. https://1890s.ca/egv4_thomson_biology/