riches--we spent several days, hunting, observing, and collecting,
almost wild with delight in, and admiration of the splendid flora and
fauna. We amused ourselves with hunting hippopotamus, and executed
justice on the crocodile; we enjoyed to the full the pleasures of
exploration and of the chase, forgetful of everything else, even of
the time we spent. But when the sun went down and tinged with gold the
varied greens of the forest; when the chattering of the parrots was
hushed and only the ecstatic song of a thrush floated down to us; when,
over there on the opposite bank, the sea-eagle, which a moment ago
had seemed like some wonderful blossom on the top of his green perch,
drowsily drew his white head between his shoulders; when silence fell
even on the guttural gossip of a band of long-tailed monkeys, who had
gone to rest on the nearest lofty mimosa; when the night came on with
its clear pleasant twilight, cool and mild, melodious and fragrant,
as it always is at this season: then would all the wealth of colour,
all the splendour and glamour of to-day’s and yesterday’s pictures
fade away. Our thoughts flew homewards, and irresistible home-sickness
filled our hearts, for in the Fatherland they were celebrating
Christmas. We had prepared our punch and filled our pipes with the most
precious of tobaccos; our Albanian companion sang his soft melancholy
song; the beauty of the night soothed our hearts and senses; but the
glasses remained unemptied, “the clouds of smoke did not bear the
clouds of melancholy with them”; the songs awoke no responsive echo,
and the night brought no solace. But it _must_ bring us a Christmas
gift, and it did!
Night in the primeval forest is always grand: the sky above may be
illumined with flaming lightning, the thunder may roll, and the
wind may rage through the trees; or it may be that the dark starless
heaven is relieved only by the slender rays of far-distant suns,
while no leaf or blade of grass is stirred. A few minutes after
sunset, night descends upon the forest. What was clearly seen by day
is now veiled by darkness, what was seen in its true proportions in
the sunlight now becomes gigantic. Familiar trees become phantasms,
the hedge-like bushes thicken to dark walls. The noise of a thousand
voices is stilled, and for a few minutes a deep silence prevails. Then
life begins to stir again, the river and the forest are again alive.
Hundreds of cicadas raise their chirping, like the jingle of many
badly-tuned little bells heard from a distance; thousands of restless
beetles, some very large, whirr about the flowering trees with a deep
humming, fit accompaniment to the cicadas’ chirping. Frogs add their
single note, surprisingly loud for their size, and their voices ring
through the forest, like the sound of a slowly-beaten Chinese gong. A
great owl greets the night with its dull hooting; a little screech-owl
responds with shrill laughter; a goat-sucker spins off the single
strophe of his rattling song. From the river come the plaintive cries
of a nocturnal member of the gull family, the skimmer or shearwater,
which begins to plough the waves, skimming along the surface of the
water; from the islands and banks sound the somewhat screeching cries
of the thickknee or stone-curlew, and the rich, melodious, song-like
trills of the redshank or the plover; among the reeds and sedges of a
neighbouring pool croaks a night-heron. Hundreds of glowworms sparkle
among the bushes and the tree-tops; a gigantic crocodile, which had
left its sand-bank before sundown to bathe its heated coat of mail in
the tepid water, is swimming half beneath and half above the surface
of the water, and making long streaks of silver which shine in the
moonlight, or at least glitter in the flickering light of the stars.
Above the tallest trees float noiseless companies of horned and other
owls; long-tailed night-jars fly with graceful curves along the river
bank; bats describe their tortuous course among the trees; fox-bats
and fruit-eating bats cross from bank to bank, sometimes in flocks.
This is the time of activity among the other mammals too. A jackal
utters its varied call, now plaintive, now merry, and continues
with equal expressiveness and persistence; a dozen others join in at
once, and strive in eager rivalry for the victor’s crown; some hyænas
who seem just to have been waiting for these unrivalled leaders to
begin, join the chorus. They howl and laugh, moan piteously, and shout
triumphantly; a panther grunts, a lion roars; even a hippopotamus in
the river lifts up his paltry voice and grunts.
Thus does night reveal itself in the primeval forest; thus did it claim
ear and eye on that never-to-be-forgotten day. Beetles and cicadas,
owls and goat-suckers had begun: then a loud, rumbling noise, as of
trumpets blown by unskilful mouths, resounded through the forest. At
once the songs of our Albanian, and the chattering of our servants
and sailors were hushed; all listened as we did. Once more came
the trumpeting and rumbling from the opposite bank. “_El fiuhl, el
fiuhl!_” called the natives; “Elephants, elephants!” we, too, exclaimed
triumphantly. It was the first time that we had seen and heard the
giant pachyderms, though we had constantly trodden their paths and
followed their traces. From the opposite bank the great forms, which
could be plainly enough seen in the twilight, descended leisurely and
confidently to the water, to drink and bathe. One after another dipped
his supple trunk in the water, to fill it, and discharge it into his
wide mouth, or over his back and shoulders; one after another descended
into the river to refresh himself in the cooling flood. Then the
noises became so great that it seemed as if the elephants’ trumpeting
had acted as an awakening call. Earlier than ever before, the king of
the wilderness raised his thundering voice; a second and a third lion
responded to the kingly greeting. The sleep-drunken monkeys and the
timid antelopes cried out in terror. A hippopotamus reared his uncouth
head quite close to our boat, and growled as if he would emulate the
lion’s roar; a leopard also made himself heard; jackals gave vent
to the most varied song we had ever heard from them, the striped
hyænas howled, the spotted ones uttered their hellish, blood-curdling
laughter, and, careless of the uproar which the heralds and the king
of the forest had conjured up, the frogs continued to utter their
monotonous call, and the cicadas their bell-like chirping.
Thus was the “Hosanna in the Highest” sung in our ears by the primeval
forest.
THE MIGRATIONS OF MAMMALS.
The love of travel, as we understand it, is not found among animals,
not even among the birds, whose sublime powers of flight over land and
sea so much excite our envy. For no animals wander, careless and free,
like the travellers who go forth to study the manners and customs of
other lands; they cling to the soil even more closely than we do, and
they are bound to the place of their birth, by habit or indolence, more
closely than we are by our love of home. When it does happen that they
forsake their birthplace, it is in obedience to stern necessity,--to
escape impending starvation. But want and misery are too often their
lot in the joyless lands to which they migrate, and so they experience
little but the pain and toil of travel.
This holds true of wandering fishes and of migrating birds, but more
particularly of those mammals which undertake periodic migrations. Few
of them do this with the same regularity, but all do it for the same
reasons, as fishes and birds. They migrate to escape from scarcity of
food, already felt or at least threatening, and their journeying is
therefore rather a flight from destruction than a striving to reach
happier fields.
By the migrations of mammals I mean neither the excursions which result
in an extension of their range of distribution, nor the ordinary
expeditions in search of food, but those journeys which lead certain
mammals, at regular or irregular intervals, far beyond the boundaries
of their home, into countries where they are compelled to adopt a mode
of life which is foreign to them, and which they will abandon as soon
as it is possible, or seems possible to do so. Such journeys correspond
closely to the regular migrations of fishes and birds, and a knowledge
of the former helps us to an understanding of the latter.
Excursions beyond their actual place of sojourn are made by all
mammals for various reasons. Males, particularly old males, are
more inclined to roam about than the females and the young of their
species, and forsake one district for another without apparent reason;
the younger males among gregarious species are often driven out and
forced to wander by the old leaders of the herd; mothers with their
young are fond of rambling about the neighbourhood where the latter
were born; and the two sexes wander about in search of one another.
During such expeditions the animal chances to light on what seems to
him a promising dwelling-place, a district rich in food, a sheltering
thicket, or a safe hiding-hole. He stays there for some time, and,
finally, it may be, settles down in this new Canaan. Experienced
sportsmen know that a preserve in which all the game has been shot
will sooner or later receive reinforcements from without, and, under
favourable circumstances, will be peopled anew; and all must have
noticed that a fox or badger burrow is not easily destroyed, for it
finds new occupants again and again, however ruthless the persecution
to which they may be subjected. As it is with game, whose coming and
going, appearing and disappearing are noted by thousands, so is it with
other mammals which are less eagerly watched. A constant emigration
and immigration cannot be denied. In consequence of this, the range
of distribution of any species is constantly being extended, unless
hindered by physical conditions, or by human and other enemies.
[Illustration: Fig. 35.--A Wild Duck defending her Brood from a Brown
Rat.]
Till the end of the first half of last century our forefathers
shared their dwellings with the black rat, and knew the brown rat
only by hearsay, if at all. The first was a rat with many, but not
all the vices of its race. It lived in our houses, ate grain, fat,
and all kinds of provisions, gnawed doors, boards, and furniture,
racketed at night like a noisy ghost through old castles and other
spook-favouring buildings, caused much annoyance, many a fright,
strengthened superstition and the fear of ghosts in many a mind; but
it was possible to live with it, one could manage to get along. A
capable cat held it in check; a skilful rat-catcher was more than a
match for it. Then its most terrible enemy appeared, and its star began
to wane. In 1727, swarms of brown rats, which seem to have come from
India, either directly or by way of Persia, were seen to swim the
Volga, and we soon learned what awaited Europe. Following canals and
rivers, the brown rats reached villages and towns, entered, in spite
of men and cats, the lower stories of our dwellings, filled vaults and
cellars, ascended gradually to the garrets, ousted its relative after
long and inexorable warfare, made itself master in our own houses, and
showed us in a thousand ways what a rat could do. It possessed and
exercised _all_ the vices of its family, mocked at all our attempts to
drive it away, and remained in possession of the field, which, up till
now, we have tried to wrest from it with dogs and cats, by traps and
snares, poison and shooting. Almost at the same time as it swam over
the Volga, it reached Europe by another route, coming from the East
Indies to England on board ship. Then began its world-wanderings. In
East Prussia it appeared as early as 1750, in Paris three years later,
Central Germany was conquered in 1780, and here, as everywhere else,
the towns were first colonized, and the flat country round taken in
by degrees. Villages not easily reached, that is to say, not lying on
river-banks, were only invaded in the last decade of this century: in
my boyhood it was still unknown in my native village, and the black
rat, now being crowded out even there, held undisputed possession of
many places where its rival now reigns supreme. Many isolated farms
were only reached later, about the middle of the present century, but
the victorious march still goes on. Not content with having discovered
and conquered Europe, towards the end of last century the brown rat
set out on new journeys. In the sea-ports already colonized, the rats
swam out to the ships, climbed on board by the anchor chains, cables,
or any other available ladders, took possession of the dark, protecting
hold, crossed all seas, landed on all coasts, and peopled every country
and island, where its chosen protector and compulsory host--civilized
man--has founded homesteads. Against our will we have helped it, or at
any rate made it possible for it, to carry out a greater extension of
range than has been attained by any other mammal not in subjection to
man.[56]
Another remarkable illustration of wandering is afforded by the
souslik, a destructive rodent about the size of a hamster, belonging
to the family of squirrels and sub-family of marmots. Eastern Europe
and Western Siberia are its head-quarters. Albertus Magnus observed
it in the neighbourhood of Ratisbon, where it is now no longer found,
though it has recently appeared in Silesia. Forty or fifty years ago it
was unknown here, but, at the end of the forties or beginning of the
fifties, it appeared no one could tell whence, and from that time it
has pressed slowly westward. Its migrations, too, have been helped by
man, for, though it is not confined to cultivated fields, these afford
the habitat most suited to its taste.
The same holds true of many species of mice, which extend their
territories as the soil is cultivated. On the other hand, man narrows
the possible range of many mammals by deforesting, by draining
marshes, and by otherwise changing the character of whole tracts of
country. In this way, far more than by direct persecution, he does
much to influence the migration of the mammals which have established
themselves in these areas. For the fundamental law holds good for
mammals as for other creatures, that suitable districts, and these
only, will be colonized sooner or later, notwithstanding the arbitrary
and usually rough and cruel interference of man.
Quite different from such wanderings are the expeditions made
by mammals to secure a temporary betterment. These are probably
undertaken, if not by all species, at least by representatives of
every family in the class; they vary in duration and distance, and
may even have the character of true migrations, but they always come
to an end after a certain time, and the wanderer ultimately returns
to his original place of abode. The intention or hope of reaching
better grazing or hunting grounds, the desire to profit by some casual
opportunity for making life more comfortable, may be said to be the
chief motive of such expeditions. They take place all the year round,
in every latitude and longitude, even in districts where the conditions
of life do not vary materially at different times. The mammal begins
and ends them either alone or in bands, companies or herds, according
as it is wont to live with its fellows; it follows the same routes with
more or less regularity, and appears at certain places at approximately
the same time, yet it is always guided by chance circumstances.
When the fruits of the sacred fig and other trees surrounding the
temples of the Hindoos are beginning to ripen, the Brahmins who tend
temple and trees await with unctuous devotion the arrival of their
four-footed gods. And not in vain, for the two divinities, Hulman and
Bunder, two species of monkey, unfailingly appear to strip the luscious
fruits from the trees piously planted and tended for their benefit,
and also to rob and plunder in the neighbouring fields and gardens as
long as it is worth while. Then they disappear again, to the sorrow
of their worshippers and the joy of the other inhabitants of India,
whose possessions they have ravaged, as they gathered in their spoils
in their usual ruthless fashion. In Central Africa, when the chief
cereal of that country, the dhurra or Kaffir-millet, comes to maturity,
a dignified and inventive baboon, tried and experienced in all the
critical situations of life, leads down the flock of which, as leader,
he is justifiably proud, to see whether Cousin Man has been good
enough to sow the nutritive grain for him this year also. Or, about
the same time, a band of long-tailed monkeys, under not less excellent
leadership, approaches the edge of the forest in order not to miss the
right moment for a profitable, and, as far as possible, undisturbed
ravaging of the fields. When the golden orange glows among the dark
foliage in South American plantations, the capuchin monkeys make their
appearance, often from a great distance, to share the fruit with
the owner. Other plant-eaters too are led by the hope of gaining an
easier livelihood into regions and districts which they usually avoid;
insectivores periodically follow the insects when they are for the time
abundant at this place or that, and large beasts of prey keep in the
wake of herbivorous mammals, especially of the herds belonging to man.
The lion journeys from place to place, following the wandering herdsmen
on the steppes of Africa; Russian wolves followed close on the retreat
of Napoleon’s defeated army, pursuing the unfortunate fugitives as far
as the middle of Germany. Otters undertake land journeys to get from
one river-basin to another; lynxes and wolves in winter often traverse
very wide stretches of country. Such journeys bring about a change of
residence, but they do not constitute a migration in the true sense
of the word. It is only exceptionally, too, that they are undertaken
from real necessity, which we must look upon as the cause of all true
migrations; in most cases they are undertaken simply to gratify a
passing desire.
Quite otherwise is it with those mammals which, every year about the
same time, leave their habitat for some other region often far distant,
from which at a definite time they will return to their former abode.
These migrate; for they do not seize a chance opportunity, but obey,
consciously or unconsciously, a compelling necessity.
The fundamental cause of all true migration among mammals, is some
very distinct and decided seasonal change. In countries of everlasting
spring true migrations do not take place, for want is never imminent.
Summer must contrast with winter, whether the latter bring frost and
snow, or heat and drought; scarcity must alternate with superfluity
before the sluggish mammal makes up its mind to migrate.
To a slight extent migrations take place among all mountain animals.
The chamois, the steinbock, the Alpine hare, the marmot all migrate
when the snow begins to melt, or a little later; they clamber over
hillsides and glaciers to the heights above, where the pasturage, now
laid bare, promises rich and abundant nourishment, and they return to
the lower slopes of the mountain before winter sets in. The bear, by
nature omnivorous, by habit a thief, undertakes a similar migration at
the same season, and completes it before winter sets in,--at least so
it is in the mountains of Siberia; the various wild cats and dogs which
live among the mountains do the same. Such changes of residence occur
also on the mountains of southern countries, even of those lying within
the tropics. In India and Africa certain species of monkey ascend and
descend the mountains at regular intervals; elephants seek the high
grounds on the approach of summer, the low grounds in winter; on the
Andes in South America the guanacos flee before the snow into the
valleys, and before the summer-heat to the shoulders of the mountains.
All these migrations are confined by the mountains within comparatively
narrow limits. They only involve a change of altitude of from three
to nine thousand feet, or a journey which may be accomplished in
a few hours, or, at most, in a few days. They have, however, the
regularity characteristic of true migrations, especially in the precise
periodicity of their occurrence, and not less in the constant choice of
the same routes.
Highlands and plain, sea and air, offer a much wider field than the
mountains, and therefore the migrations of the animals inhabiting, or
temporarily traversing these can be more easily observed, and they are
more appropriately termed migratory animals than the dwellers among
the mountains. In the tundras of Russia and Siberia, the reindeer,
which, in Scandinavia, never leaves the mountains, migrates to a great
distance every autumn and returns the following spring to his former
summer haunts.[57] About the same time it leaves Greenland, and,
crossing the sea on a bridge of ice, reaches the continent of America,
where it spends the whole winter, only returning to the hills of its
native peninsula the following April. In both cases, dread of the
approaching winter does not seem to be the sole cause of migration;
there is at the same time a further incentive supplied by a plague
much feared in the far north. For the short summer on these expanses
calls to life an insect-world poor in species, but endlessly rich in
individuals, particularly an indescribable number of mosquitoes and
bot-flies, which make life a burden to the reindeer, as well as to man.
To escape these the reindeer forsakes the marshy tundra, over which
dense clouds of mosquitoes hover during summer, and hies to where the
scourge is less severely felt--to the Alpine heights, which, in the
summer season afford their most fragrant pasturage. From inherited
habit, the reindeer migrate not only at the same time, but along
the same paths, thus forming tracks which may be distinctly traced,
traversing the tundra for many miles, and crossing streams and rivers
at definite places. At the beginning of the journey, the cows with
their calves arrange themselves in herds of from ten to a hundred, and
precede the young stags and hinds, which are followed again by the old
stags. One troop follows directly behind another, and the observer can
count thousands as they pass. All hurry incessantly on, turning aside
neither for the mountains nor the broad streams which cross their path,
and resting only when they have reached their winter-quarters. Packs
of wolves, bears, and gluttons follow close on their heels and often
pursue them no small part of the way. In spring, on the return journey,
the animals keep to the same order, but the herds are much smaller, and
they travel in a much more leisurely fashion, and keep less strictly to
the paths by which they went.
Journeys still longer than those of the reindeer are taken by the
American bison, the “buffalo” of the prairies.[58] What distance
individual animals travel cannot be stated with certainty, but herds
in course of migrating have been met from Canada to Mexico, from
the Missouri to the Rocky Mountains, and it may be assumed that
a single herd traverses a considerable part of the country lying
between these limits. The bisons have been seen in summer scattered
over the boundless prairie, and in winter in the same places, but
assembled in many thousands; their migrations have been observed, for
they have been followed for hundreds of miles along the tracks--the
so-called “buffalo-paths”, trodden out straight across plains and over
mountains. We learn from eye-witnesses that a stream a mile wide is to
them no barrier, scarcely even a hindrance, for they throw themselves
into it like an irresistible avalanche, so that the water is covered
with the dark, moving throng; that the animals associate and separate
again, the herds increase and diminish; that old, surly, tyrannous,
malevolent bulls avoid the other bisons, having perhaps been expelled
from the herd, and compelled, probably only after protracted struggles,
to live in hermit-fashion until the following summer; and that, during
heavy snowfalls, the herds take shelter in the forests or on the
slopes of the mountains. From July onwards they begin their migrations
from the north towards the south. Small companies, which, till then,
have been leading a comfortable summer life, combine with others and
set out on the journey with them; other troops join the band, which
grows as it presses on, until there is, at length, formed one of those
extraordinary herds which, united till the next spring, moves and acts
as if animated by one soul. When the winter is safely past, the army
gradually breaks up, probably in exactly reverse order, into herds,
and these divide more and more until at length only small companies
are left. This breaking-up takes place during the course of the return
journey. Both in going and returning, one herd follows another at some
distance, but more or less along the same paths. Specially favourable
places, such as low grounds covered with rich grass, cause a temporary
damming up of the living stream. In such places incalculable herds
assemble together, spend days in the same spot, and break up only again
when all the grass has been eaten, and hunger urges them to continue
their journey. As they march the wolves and bears follow their track,
while eagles and vultures, birds of ill omen, circle over their heads.
[Illustration: Fig. 36.--A Herd of American Bison or Buffalo.]