PROVISIONS AND DOMESTIC ANIMALS.
PROVISIONS LAID UP FOR A SHORT PERIOD--PROVISIONS LAID UP FOR
A LONG PERIOD--ANIMALS WHO CONSTRUCT BARNS--PHYSIOLOGICAL
RESERVES--STAGES BETWEEN PHYSIOLOGICAL RESERVES AND
PROVISIONS--ANIMALS WHO SUBMIT FOOD TO SPECIAL TREATMENT IN
ORDER TO FACILITATE TRANSPORT--CARE BESTOWED ON HARVESTED
PROVISIONS--AGRICULTURAL ANTS--GARDENING ANTS--DOMESTIC
ANIMALS OF ANTS--DEGREES OF CIVILISATION IN THE SAME SPECIES
OF ANTS--APHIS-PENS AND PADDOCKS--SLAVERY AMONG ANTS.
The industries of the chase which are derived immediately from the
most imperious of needs--that of assuring the existence of the
individual--never arrive at a very extraordinary degree of perfection;
or at all events, as they are indispensable to existence, we are not
surprised at their development. It is unquestionable that an industry
marks a higher degree of civilisation not only by its development, but
still more by its reference to the less necessary things of life; in
every species the importance of the place given to the superfluous is
a mark of superiority. The animals who, foreseeing a hard season, or
fearing the days when hunting will not be productive, lay up
provisions to utilise in such times of famine, rise a degree higher
than even the most skilful hunters. Not all amass with the same
sagacity, and we shall find different examples of foresight, from the
most rudimentary to the highest, very near what we may observe in Man.
The provisions harvested by animals have more than one destination:
some are for the individual himself who has gathered them; others, on
the contrary, are to serve as the food for his young at the age when
they are not yet capable of seeking their own food. I will deal with
these latter in another chapter, and propose at present only to speak
of those animals who provision barns with the intention of themselves
profiting by them.
The foresight of the animal is so much the greater the more remote the
future for which he prepares. The Carnivora live from day to day and
lay up no stores; it is the Rodents, certain frugivorous birds, and
insects who exhibit the most complicated acts of economy.
_Provisions laid up for a short period._--As a rudimentary example of
the art of preserving food in view of possible famine, I may mention
the case of the _Lanius collurio_. I have already spoken of this bird
and of his custom in days of abundance of spitting on thorns all the
captures he has made. One may see side by side Coleoptera, crickets,
grasshoppers, frogs, and small birds. It is evident that these
reserves cannot be preserved for more than a day, or at most two days.
The bird amasses just enough to show us his apprehensions of the
possible future lack of success in hunting, and his thought of
preserving the surplus of the present in view of privations to
come.[47]
[47] Naumann, _Naturgeschichte der Voegel Deutschlands_, etc.
The Fox, a very skilful hunter, has no trouble in finding game; of all
the Carnivora he is, however, the only one who is truly foreseeing.
The others in presence of abundant food gorge themselves, and abandon
the rest at the risk of suffering to-morrow. The fox is not so
careless. If he has had the good fortune to discover a poultry yard,
well supplied but ill watched, he carries away as many fowls as he can
before dawn and hides them in the neighbourhood of his burrow. He
places each by itself, one at the foot of a hedge, another beneath a
bush, a third in a hole rapidly hollowed out and closed up again. It
is said that he thus scatters his treasures to avoid the risk of
losing all at one stroke, although this prudence complicates his task
when he needs to utilise his provisions. The fox, however, loses
nothing, and knows very well where to find his stores. The very nature
of the game prevents him from keeping it more than a few days.
_Provisions laid up for a long period._--The Rodents, who live on dry
fruits or grains, can on the other hand preserve them for a long time
in their barns. The Squirrel, who may be seen all the summer leaping
like a little madman from branch to branch, and who seems to have no
cares except to exhibit his red fleece and show off his tail, is,
contrary to appearance, a most sensible and methodical animal. He
knows that winter is a hard time for poor beasts, and that fruits are
then rare or hidden beneath the snow; in the autumn, therefore, when
all the riches of the earth are abundant, and beech-nuts, acorns, and
chestnuts have ripened, he harvests quantities of them and hides them
wherever he can. Making use of the cavities he is acquainted with
around his domain, hollow trees, holes that he makes in the earth
beneath bushes, etc., he fills them with fruits, and when winter has
come he extracts them to munch.
_Animals who construct barns._--The Field Rat of Hungary and Asia
(_Psammomys_) gathers wheat during the summer. He cuts the blades and
transports them to his home, where he stores them up in very
considerable quantities; and during rigorous winters when famine
appears also among men, gleaners of another species appear on the
scene and seek for corn under the earth in the nests of the
_Psammomys_. A single rat can store up more than a bushel. Those who
are skilful in finding their holes can thus in a day glean a good
harvest, to the detriment of the rats who are thus in their turn
reduced to beggary.
The Hamster also makes provision of grain, but he introduces two
improvements: the first at the harvest by only taking the edible part
of the ear, and the second by constructing barns distinct from his
home. Each possesses a burrow composed of a sleeping chamber, around
which he has hollowed one or two others communicating with the first
by passages, and intended to serve as barns. The old and more
experienced animals prepare even four or five of these storehouses.
The end of summer is their season for work. They scatter themselves in
the fields of barley or wheat, pull down the stalks of the cereals
with their anterior paws, and then cut off the ear with their teeth.
This done, they set about thrashing their wheat--that is to say, they
separate the grain from the straw by turning the ear round and round
between their paws. When the grains come out they pile them up in
their cheeks, and thus transport them to one of the chambers already
mentioned; they then return to exploit the field and continue these
labours until they have completed the stores for winter.
A certain Vole (_Arvicola economus_) acts in much the same way as the
Hamster, though he harvests a different class of objects. It is not
wheat which he collects but roots. He has to find these roots, to dig
them up, to cut them into fragments of suitable dimensions for
transport, and finally to pile them up in rooms disposed to receive
them. This species, which inhabits Siberia, measures about twelve
centimetres in length, but during summer and autumn Voles accomplish
an amount of work which is surprising having regard to their size. The
moment having arrived to think about winter, the Voles spread
themselves about the steppe. Each hollows little pits around the roots
he wishes to extract. After having bared them he cleans them while
still in position, so as not to encumber his storehouses with useless
earth. This preparatory labour having been completed, he divides the
root into slices of a weight proportioned to his strength, and carries
away the fragments one by one. Seizing each with his teeth, he walks
backwards drawing it after him, and thus traverses a long road,
crossing paths, going round tufts of grass or other obstacles, not
letting himself be rebuffed by the difficulty and length of the task.
Arrived at his hole, he enters this also backwards, drawing his burden
through all his galleries. His dwelling, though the entrance is rather
more complicated, resembles that of the Hamster. Like the latter, it
is composed of a central room placed in communication with the outside
by a maze of passages, which cross one another. That is the
sleeping-room, the walls of which are well formed, and which is
carpeted with hay. From this various underground passages start which
lead to the storerooms, which are three or four in number. It is to
these that the Vole bears his harvest. Each compartment is large
enough to contain four or five kilogrammes of roots, so that the
little rodent finds himself at the end of the season the proprietor of
about fifteen kilogrammes of food in reserve. He would have enough to
enable him to revel in abundance if he were able to reckon without his
neighbours. This diligent animal has in fact one terrible parasite.
This is Man, who will not allow him to enjoy in peace the fruits of
his long labour and economy. In Siberia, a long and severe winter
follows a very hot summer; in this season the inhabitants often lack
provisions. A moment comes when they are glad to make up for want of
bread by edible roots; but the search for these is long and
troublesome, and should indeed have been thought of during summer.
Man, during the fine weather less foreseeing than the rodent, does not
hesitate when famine has come to turn to him for help. As he is the
weaker, the Vole is obliged to submit to this vexatious tax. According
to Pallas,[48] the inhabitants seek these nests full of provisions and
dig them up. The conqueror takes all he pleases, and abandons the rest
to the unfortunate little beast, who, whether he likes it or not, has
to be content. In this region the burrows of the Vole abound;
therefore this singular tithe ensures a considerable revenue to those
who levy it, as may be understood when we remember the extent of the
stores amassed by the animal.
[48] Pallas, _Ueber d. am Volgastrome bemerkten Wanderungen
der grossen Wassermaeuse (Arvicola amphibius),
Nord--Beitr._, vol. i., 1781, p. 335.
A Vole resembling the _Arvicola arvalis_, but larger, paler, and more
rat-like, with large shining eyes and very short tail, overran in
1892-93 the classic land of Thessaly, the land of Olympus, and the
Vale of Tempe. It has always inhabited this region, and the old Greeks
had an Apollo Smintheus, or Myoktonos, the Mouse-destroying God. "At
the beginning of March," according to Prof. Loeffler, who has given an
account of this invasion,[49] "the Voles were only beginning to troop
from the slopes of the hills and the fallow-lands to the cultivated
fields. It was frequently observed that they followed regular paths
during their inroads. Thus they advanced along the railway embankment.
Their progress seemed to be rather slow. Perhaps they do not advance
further till the inhabitants of one of their strongholds or so-called
castles have become too numerous. The runs which they excavate are at
a depth of about twenty to thirty centimetres below the surface of the
ground. The extent of their runs varies, and we found them extending
in length from thirty to forty metres and more. These runs are
connected with the surface by vertical holes of about five centimetres
in diameter. In many places four, five, and more holes have led to the
same run. In such cases there is generally, not far off, an
enlargement for the nest, lined with finely-ground vegetable material,
where the young are produced and reared. In front of newly-opened
holes the earth, which has been thrown far out, forms smooth hillocks.
There were many well-defined and well-trodden paths on the ground, by
which the Voles pass from one hole to another. They are never seen out
of their holes by day, not even in places where the entire ground is
riddled with holes like a sieve. They do not come out in search of
food till the evening; even then not many are to be seen, but the
peculiar squeaking noise they make is to be heard everywhere. Next day
all sorts of freshly-severed plants are to be found in the holes.
Stalks of corn they manipulate by standing on their hind legs and
gnawing through the stalk; when this is bitten off they drag it into
their holes to devour it there, sometimes making it smaller. They do
their work with amazing rapidity. One evening a field was visited
which was to be mowed next day, but when the labourers came in the
morning they found nothing to cut. The Voles had destroyed the entire
crop in a single night. A miller in the neighbourhood of Velestino
reported that he went to his field early one morning, cut a measure of
corn, loaded it on his ass, and brought it to his mill. When he
returned to his mill with a second load he found scarcely a vestige of
the first remaining. Thinking it had been stolen he kept watch for the
thief; but suddenly, to his great astonishment, hosts of Voles
appeared and set to work to carry off the second load." Such facts as
these recorded by Loeffler are by no means a merely recent phenomenon;
Aristotle was familiar with the devastations of the Voles, and wrote
that "some small farmers, having one day observed that their corn was
ready for harvest, when they went the following day to cut their corn,
found it all eaten." Other ancient writers record similar facts.[50]
[49] _Centralblatt f. Bak. u. Parasitenkunde_, July 1892,
and _Zoologist_, September 1892.
[50] _Zoologist_, May 1893. It may be added that the
Scottish Vole, which was so destructive about the same time,
does not burrow to a depth like the Thessaly Vole, but lives
in shallow runs amongst the roots of herbage. Its exploits
are recorded in a Report on the Plague of Field-Mice in
Scotland, made by a committee appointed by the President of
the Board of Agriculture, 1893.
Two birds of North America, belonging to the Woodpecker family,
prepare their provisions for the bad season with consummate art; not
only do they harvest them and place them in shelter, but they arrange
them in such a manner that at the right moment they can utilise them
in the most convenient manner.
One of them which is common in California, the _Melanerpes
formicivorus_, nourishes himself, as his name indicates, by insects,
and especially ants. All the summer he gives himself up to this hunt,
but at the same time he collects acorns, which he does not touch,
however, so long as he can find other food. He amasses them in the
following ingenious manner: he chooses a tree and hollows out in its
trunk a cavity just capable of receiving one acorn. He then carries a
fruit and introduces it forcibly into the hole he has just made. Thus
buried, the acorn can neither fall nor become the prey of another
animal. In the domain of these birds trees may be found which are
riddled like a sieve with holes stopped up by an acorn as by a plug.
When the hunting of insects ceases to be fruitful, the _Melanerpes_
visits his barns. If an ordinary bird wished to eat one of these
fruits, at each stroke of his beak, on account of the polish and
convexity of the acorn's surface, it would escape him, and only by a
series of reiterated efforts would the interior be exposed; but for
the American woodpecker the task is simplified; each acorn being
maintained firmly in the bark, it is sufficient to break the envelope
and the pulp is easily seized.[51]
[51] See, for instance, _Nature_, 20th July 1871; also A. L.
Heermann, "Notes on the Birds of California," _Journ. Acad.
Nat. Sc. Philadelphia_, 2nd Series, vol. ii., 1853, p. 259.
A relation of this bird, the _Colaptes mexicanus_, does not yield to
him in economy and skill. He places his barn in the interior of a
plant which is very abundant in the zone he inhabits. Insectivorous
during a part of the year, he is forced to renounce this diet during
the dry season. In the regions of Mexico where this bird is found the
dry period is so absolute that he would die of hunger for want of
insects or fruits if he had not taken the precaution of laying up
stores during spring. His store consists of acorns. He has not time to
fix them one by one, like the _Melanerpes_, and only thinks at first
of rapidly collecting a large quantity. But it is in deciding the
question as to where they are to be laid up that the _Colaptes_ shows
his remarkable intelligence. In the forests where he lives are to be
found aloes, yuccas, and agaves. When the agaves have flowered, the
flower-bearing stem, two or three metres in length, shrivels, but
remains standing for some time. Its peripheral portion is hardened by
the heat, while the sap in the interior almost entirely disappears. A
hollow cylinder with a well-sheltered cavity is thus formed, and the
_Colaptes_ proposes to utilise it as a storehouse. His acorns will
there be well protected against external influences and against the
birds whose beaks are too weak to pierce the agave. It is then a
question of filling the tube. The animal first pierces the wall
towards the base of the stalk; through this hole he introduces acorns
until he has filled the lower part of the cavity. This done, he makes
a new hole rather above the first, and fills the interval between the
two, continuing this process until he has arrived at the top of the
stalk and filled the whole interior. (Figs. 10 and 11.) The bird seems
at first to take unnecessary trouble by boring so many holes. He would
reach his end as well, it would seem, by making a single hole at the
top to fill his storehouse, and another at the bottom to empty it. But
we must not thus accuse him of lack of judgment. The interior of the
tube is just large enough for the passage of an acorn; but at certain
points the sap is not entirely absorbed, and there might easily be an
impediment which would leave a large part of the cavity empty. Hence
the necessity for a number of openings. When the sun has scorched up
plants, and provisions are rare, he turns to his barns of abundance.
Now and every time that he has need he can utilise the method that has
been employed by his cousin the _Melanerpes_. In order to feed on each
acorn without too much trouble, or allowing it to slip from his beak,
the bird places it in a vice. He hollows a hole in the trunk of a
tree, introduces the fruit there forcibly, and eats it at his
ease.[52]
[52] Henri de Saussure, "Observations sur les moeurs de
divers oiseaux du Mexique," _Arch. Sci. phys. et natur._,
1859, pp. 21-41.
[Illustration: FIG. 10.]
[Illustration: FIG. 11.]
The provisions collected by these two birds reveal a remarkable fact.
They possess indeed two distinct diets; they do not preserve for the
period of famine the overplus of the foods which they consume in the
period of abundance. They chase insects and feed on them as long as
they can find them, while they gather up in their storehouses an
entirely different food.
_Physiological reserves._--All the animals of which I have just spoken
place their provisions for the future in barns in the same manner as
Man. Those who have not this foresight are either able to nourish
themselves in all seasons by the chase, or else, after having feasted
one half of the year, they fast during the other half. In the latter
case they consume during the fasting period a portion of their own
substance, and use up materials placed in reserve in their organism,
in the form of fat for example. This arrangement, which allows them to
prolong life, though growing thin, until the next season of
prosperity, is not under the control of the will. It is a complication
of physiological phenomena resulting from the functioning of different
parts of the organism.
_Stages between physiological reserves and provisions._--Between
physiological reserves and industrial stores we may place as an
intermediate stage the interesting case of the Honey Ants.[53]
[53] H. C. McCook, _The Honey Ants of the Garden of the
Gods, and the Ants of the American Plains_, Philadelphia,
1882.
[Illustration: FIG. 12.]
[Illustration: FIG. 13.]
These insects (_Myrmecocystus_) live in Texas, and form colonies in
which certain individuals play a very special part They exaggerate to
an extreme point the power of preserving provisions in their crops.
These materials are not assimilated; they do not form part of the
animal's body, and although placed inside it cannot be compared to
physiological reserves. It is especially curious that they are not to
be utilised only by the animal itself, but also by the other members
of the colony who are not able to form such stores. Among the
_Myrmecocystus_ there are workers of two sorts; the first kind
resemble other ants with some differences of detail, and build and
hollow the earth nest which shelters the community. The second kind is
quite different; the abdomen in these workers is enormously distended
so as to constitute a voluminous sphere, which may become four or five
times larger than the thorax and head together. (Fig. 12.) On this
distended receptacle appear several darker plates; these are the
remains of the chitinous parts of the primitive wings. In the fine
season these ants go out in a band and collect a sweet liquor which
forms pearly drops on certain galls of oak leaves. These drops,
elaborated into honey, gradually fill the crop, distending it and
pushing back neighbouring organs until it receives its globular form.
When they have arrived at this obese condition, the heavy honey ants
no longer leave the nest. They remain without movement, hanging by
their legs to the roof or lying against the walls of a room. The
workers who have remained slender come and go, attending to their
usual occupations, and pass near the others without paying attention
to them or going out of the way to lend assistance to their impotent
sisters when one of them has rolled over on the ground and can no
longer arise unaided. (Fig. 13.) They only cease to be indifferent
when impelled by the selfish sentiment of hunger, and then it is to
ask and not to give assistance. The fat ants in fact could not
themselves consume all the honey that they have elaborated; the others
in times of famine approach them, caress them with their antennae, and
obtain by solicitation a drop of honey which the large ones disgorge
from the crop. Here, then, is a colony in which the division of labour
has reached a remarkable degree of polymorphism. Some of the members
accomplish the work of engineers and masons, while the others
fabricate for the community a store of honey. Instead of depositing
these provisions in cells like bees, they preserve them in their own
digestive tube. This custom has re-acted to such an extent on the form
of their bodies that at first sight they seem to belong to a different
species.
[Illustration: FIG. 14.]
_Animals who submit foods to special preparation in order to
facilitate transport._--Not content with collecting materials as they
are found in nature, certain animals submit them to preparation with
various aims, either to render transport easier or that they may not
deteriorate when stored. Among those of whom I have just spoken, some
collect with the view of utilising their stores in a more remote
future than others. The _Ateucus sacer_ intends to consume the
provisions he prepares almost immediately. Yet he acts in so careful a
manner that I cannot pass him in silence. This beetle is the sacred
Scarabaeus so venerated by the Egyptians, who have everywhere
reproduced his image in porphyry and granite. He is a most singular
insect. The celebrated Fabre has given a complete and very picturesque
history of his customs.[54] I have myself had an opportunity of seeing
him at work. It was in Persia, in the plain of Susiana, on a hot
morning in March. We had passed the night in the open air, proposing
to continue our journey in the early morning, but our mules, rendered
rather lively by the fresh grass brought out by the spring weather,
had decided otherwise. They had all decamped to take a ramble on their
own account. In order to pass away the hours taken up by the muleteers
in searching for the strayed animals, the Scarabaeus would, I thought,
furnish me with an amusing and instructive spectacle. During the night
the mules had not failed to leave here and there the relics of their
digestion. The aroma, borne on the morning breeze, had struck the
Scarabaeus on awaking. It was his favourite dish. From all points of
the sky their heavy silhouettes could be seen against the blue. It was
still fresh, the sun having only risen about an hour before; the heat
would soon become oppressive, and the sybaritic beetle, without
attending to his morning appetite, which his fresh meal could not fail
to excite, nourishes the bourgeois dream of making his little pile in
order to enjoy himself sheltered from the hot rays. Immediately on
arriving on the scene of the accident each began to display feverish
activity. All set to work. With their heads, the anterior edge of
which is flat and supplied with six strong spines, they raised their
provisions; with their anterior feet, which are large and also armed
with spines, they moulded the paste and placed it beneath the abdomen
between the four other legs, giving it a rounded form. Little by
little the sphere increased and acquired the size of a small apple.
That was sufficiently large, and besides it was already becoming hot.
The insect set about carting away his prize to a sheltered
dining-room. He placed his four posterior legs on the ball; with the
two last, which were continually moving, he made certain of the
equilibrium of the mass; then resting his head and two anterior feet
on the ground he pushed backwards, and with extreme rapidity. (Fig.
14.) There was enough for all; each worker could find the just reward
for his labour; I witnessed none of the regrettable facts narrated by
Fabre. It happens sometimes, according to this ingenious observer,
that a cunning Scarabaeus, who has taken no part in the laborious
labour of moulding the paste, arrives when it is on the road to aid
the convoy, or even simply to pretend to help, in order that when the
moment has come he may claim a share in the coveted meal, or even
carry it all away if he can profit by a momentary inattention on the
part of the lawful proprietor. I followed one of these Coleoptera for
more than five metres from the place where his labour began. After
having deposited his ball he began to dig up the earth around it;[55]
but the mules had returned and I was obliged to depart.
[54] J. H. Fabre, _Souvenirs entomologiques_, 1879.
[55] In captivity also, as Mrs. Brightwen found, the
Scarabaeus always attempts to bury its ball in the earth.
I have no doubt that subsequent events were not exactly the same as
narrated by Fabre for the Scarabaeus of Provence. The insect having
made his hole, buries himself in it for a _tete a tete_ with the
precious sphere. He immediately sets about passing the whole through
his body. Without haste but without rest, for a week or a fortnight,
as long as there is any of it left, he eats continuously, and
continuously digests. He does not stop for a moment, his jaws are
working the whole time; and Fabre has called attention to the fact
that from the opposite extremity of the animal a continuous thread
emerges without breaking, and becomes coiled up.
_Care bestowed on harvested provisions._--Among the animals who take
particular care of the provisions they have amassed, special mention
must be made of certain species of Ants. It was formerly believed that
these industrious Hymenoptera are not accustomed to store up in barns
for the winter. This opinion long prevailed owing to the authority of
Huber, so competent in these matters, although the ancients were well
acquainted with the storehouses of ants.[56] But it was founded on an
exclusive study of these insects in northern countries, in which,
during the cold season, they become torpid and buried in their
hybernal sleep. Naturally they have no need of food during this
period, but it was incorrect to generalise from this fact. The ants of
the south are active all the year round. An English naturalist,
Moggridge, who passed several winters at Mentone, has placed this fact
out of doubt. Suffering from an incurable disease, he occupied the
last years of his life in observing and setting down for the
instruction of others the habits of these insects. He found that ants
of the species _Atta barbara_ store up grains. They utilise plants of
various kinds, but usually fumitory, oats, nettle, various species of
_Veronica_, etc. They procure these grains towards the end of autumn,
collecting them on the soil, or even, when they do not fall in
sufficient quantities, climbing up the plants and gathering them in
position. An ant will, for instance, ascend the stem of a fruiting
plant, of shepherd's-purse, let us say, and select a well-filled but
green pod, mid-way up the stem, those below being ready to shed their
seeds at a touch. Then seizing it in its jaws, and fixing its hind
legs firmly as a pivot, it contrives to turn round and round, and so
to strain the fibres of the fruit-stalk until they snap; it then
patiently backs down the stem. Sometimes two ants combine their
efforts; one, at the base of the peduncle, gnaws at the point of
greatest tension, while the other hauls upon it and twists it. And
sometimes the ants drop the capsules to their companions below,
corresponding with the curious account given by AElian of the way the
spikelets of corn are thrown down "to the people below." In this
labour they display the activity usual in their race, and do not stop
until they have carried away to their barns the amount of provision
they desire. When their wealth is stored up in the nest, the ants pile
up the grains in some hundred little rooms designed for this purpose,
each measuring from seven to eight centimetres in diameter, and three
or four in height; the average granary being about the size of a
gentleman's gold watch. Adding up the quantities of grain divided
between these different barns, it is found that they may be estimated
at about 500 or 600 grammes, which represents a very large number of
meals for such small appetites, and must cost colossal labour if we
take into consideration the size of the workers. But when the harvest
is completed, the _Atta barbara_ have not completed their task; they
are too ingenious to limit themselves to waiting with crossed legs for
the moment to come when they may enjoy their labour, without
considering the damage that may arise. Their first care is to prevent
the grains from germinating for some weeks. How they obtain this
result is not exactly known, but it is certain that germination does
not take place, although all the conditions of heat and moisture
offered by the interior of the ant-hill are favourable to it; it is
not less certain that this arrest is due to the ants. This is shown in
a very simple manner. It is sufficient to prevent the access of the
insects to one of these chambers to cause the grains to germinate
immediately. We can only suppose some direct action of the ants, every
other hypothesis falling before this single fact: the arrested
phenomenon is produced as soon as the _Atta barbara_ no longer acts on
it. Therefore they arrest germination without rendering it impossible,
and when the moment arrives for utilising the accumulated stores,
their first care is to allow the grains to follow the normal course of
evolution. The envelope breaks, the little plant makes its appearance;
radicle and stalk come to light. But the ants do not permit the
development to go too far. The little plant, in order to grow, digests
the starch which is associated with the albumen, for it is not yet
able to draw its nourishment direct from the soil. To be absorbed and
assimilated this starch must first be transformed into sugar. This
chemical transformation being effected, the grain is in the condition
in which the ants prefer it. Like a wine-grower who watches over the
fermentation in his vat, and stops it before the wine turns sour, they
stop the digestion of the starch at this stage. If we do not know how
they retard germination, we know at all events how they render it
impossible at this later stage. It is the young plant which absorbs
the glucose, and which must therefore be destroyed; they cut off the
radicle with their mandibles, and gnaw the stalk; the germ is thus
suppressed. They have not yet finished their manipulations, which must
enable them to preserve without further alteration the provisions
which they have already rendered palatable. They bring out all their
provisions to the sun, dry them, and take them back to the barns. As
long as winter lasts they feed on this sweet flour. An anatomical
peculiarity enables them to make the most of it; their mouth is so
arranged that they can absorb solid particles and eat the albuminous
powder. In this they differ from their northern kin, who are obliged
to feed exclusively on juices.
[56] See chapter on "The Ancient Belief in Harvesting Ants,"
in McCook's _Agricultural Ants_.
I have compared the labours of these ants to those of the wine-grower.
Both of them in fact utilise the chemical phenomena going on in living
matter; both of them know how at a given moment to prevent the
transformation from going further. Neither of them for the rest take
into account the part played by diastasis and ferments. The ancestors
of one as of the other have by chance found out the method, and they
transmit it from generation to generation.[57]
[57] J. Treherne Moggridge, _Harvesting Ants and Trap-Door
Spiders_, London, 1873, pp. 16-60.
_Agricultural Ants._--The art of amassing stores is still more highly
perfected by an Ant which inhabits North America. It is called the
_Pogonomyrmex barbatus_, or, on account of its customs, the
Agricultural Ant. It carries out a certain number of preparatory acts,
and pushes foresight further than any other animal, since it looks
after its property while still growing. It is grain which these
insects collect, but only a single species of graminaceous grain. This
choice leads them to spend great trouble on their preferred plant.
They act in such a way that in the case of men we should say, purely
and simply, that they were cultivating. The art of treating the earth
with a view of augmenting the products which it yields is certainly of
all the manifestations of human activity that which we should least
expect to find among animals. It is, however, impossible otherwise to
describe the conduct of Agricultural Ants. The field which they
prepare is found in front of their ant-hill; it is a terrace in extent
about a square metre or more; there they will allow no other plant to
grow but that from which they propose to gather fruit. This latter
(_Aristida stricta_) is rather like a grain of oats, and in taste
resembles rice; in America it is called ant rice. This culture
represents for these insects a much more important property than a
wheat field for man. It is, in relation to their size, a forest
planted with great trees, in comparison with which baobabs and
sequoias are dwarfs. It is not known if the _Pogonomyrmex_ sow their
rice; Lincecum asserted that the ants actually sow the seeds, that he
had seen the process going on year after year; "there can be no
doubt," he concludes, "of the fact that this particular species of
grass is intentionally planted, and in farmer-like manner carefully
divested of all other grasses and weeds during the time of its
growth."[58] McCook is not able to accept this unqualified conclusion.
"I do not believe that the ants deliberately sow a crop, as Lincecum
asserts, but that they have, for some reason, found it to their
advantage to permit the _Aristida_ to grow upon their disks, while
they clear off all other herbage; that the crop is seeded yearly in a
natural way by droppings from the plant, or by seeds cast out by the
ants, or dropped by them; that the probable reason for protecting the
_Aristida_ is the greater convenience of harvesting the seed; but,
finally, that there is nothing unreasonable, nor beyond the probable
capacity of the emmet intellect, in the supposition that the crop is
actually sown. Simply, it is the Scotch verdict--Not proven."[59]
However it may be, they certainly allow no other plant to grow in the
neighbourhood of their grain, to withdraw the nourishment which they
wish to reserve entirely for it. Properly speaking, they weed their
field, cutting off with their jaws all the troublesome plants which
appear above the soil. They pursue this labour very diligently, and no
strange shoot escapes their investigations. Thus cared for, their
culture flourishes, and at the epoch of maturity the grains are
collected one by one and carried within. Like all harvesters, these
Hymenoptera are at the mercy of a shower that may fall during the
harvest. They are well aware that in this case their provisions would
be damaged, and that they would run the risk of germination or decay
in the barns. Therefore, on the first sunny day all the ants, as
observed by Lincecum and Buckley, may be seen carrying their grains
outside, only bringing them back when they have been thoroughly dried,
and always leaving behind those that have sprouted.[60]
[58] Lincecum's most important published paper on the habits
of the _Myrmica molefaciens_ appeared in the _Proc. Acad.
Nat. Sci. Philadelphia_, vol. xviii., 1866, p. 323-331. See
also Darwin, _Proceedings of the Linnaean Soc._, 1861.
[59] H. C. McCook, _Natural History of the Agricultural Ants
of Texas_, Philadelphia, 1879, pp. 33-39.
[60] McCook, _Agricultural Ants of Texas_, pp. 105-107.
_Gardening Ants._--The Leaf-cutting Ants (_Oecodoma_) of tropical
America are often alluded to by travellers on account of their ravages
on vegetation; and they are capable of destroying whole plantations of
orange, mango, and lemon trees. They climb the tree, station
themselves on the edge of a leaf and make a circular incision with
their scissor-like jaws; the piece of leaf, about the size of a
sixpence, held vertically between the jaws, is then borne off to the
formicarium. This consists of low wide mounds, in the neighbourhood of
which no vegetation is allowed, probably in order that the ventilation
of the underground galleries may not be interfered with.
For a long time there was considerable doubt as to the use to which
the leaf-cutting ants put the leaves; some naturalists supposed they
are used directly as food, others that the ants roof their underground
dwellings with them. The question was set at rest by Fritz Mueller, who
observed these ants in Brazil,[61] and independently by Belt, who
studied them in Nicaragua, and has written an interesting account of
their proceedings.[62] The real use of the leaves is as manure on
which to grow a minute species of fungus; these ants are, in reality,
mushroom growers and eaters. Belt several times exposed the
underground chambers to observation and found that they were always
about three parts filled with "a speckled, brown, flocculent,
spongy-looking mass of a light and loosely-connected substance."
Scattered throughout these masses were the pupae and larvae, together
with the smallest division of workers who do not engage in
leaf-carrying, but whose duties appear to be to cut up the leaves into
small fragments and to care for the young. On examination the masses
proved to be composed of "minutely sub-divided pieces of leaves,
withered to a brown colour, and overgrown and lightly connected
together by a minute white fungus that ramified in every direction
throughout it." That they do not eat the leaves themselves was shown
by the fact that near the tenanted chambers were found deserted ones
filled with the refuse of leaves that had been exhausted as manure,
and which served as food for the larvae of various beetles. There are
numerous holes leading up from the underground chambers, and these are
opened out or closed up, apparently in order to regulate the
temperature below. Great care is also taken that the nest should be
neither too dry nor too damp; if a sudden shower comes on the leaves
are left near the entrance, and carried down when nearly dry; during
very hot weather, on the other hand, when the leaves would be parched
in a very short time, the ants only work in the cool of the day and
during the night. Occasionally, inexperienced ants carry in grass and
unsuitable leaves; these are invariably brought out again and thrown
away.[63]
[61] _Nature_, 11th June 1874. And see Appendix.
[62] _Naturalist in Nicaragua_, 2nd edition, 1888, pp. 71-84.
[63] For a brief discussion of the relation of ants to
plants generally, see Lubbock's _Ants, Bees, and Wasps_,
1882, chap. iii.
_Domestic animals of Ants._--Following through different species the
perfection reached in the art of laying up provisions for the future,
we have gradually arrived at methods resembling those of Man. But a
foresight still greater and nearer to his is manifested by those ants
who breed and keep near them animals of different species, not for the
sake of their flesh, but for certain secretions, just as man utilises
the milk of the cow or the goat. Ants have true domestic animals
belonging to a variety of species, but the most widely spread are the
_Claviger_ and the Aphides or plant-lice. To keep these insects at
their disposal, Hymenoptera act in various ways: some, who are a
little experienced, are content to take advantage of a free aphis
which chance may put in their way; others shut up their cattle in
stables situated in the midst of the ant-hill, or else pen them in the
country at a spot where they can best find their food. These facts
have long since been carefully studied and leave no room for doubt.
The _Claviger testaceus_ is a small beetle, often met in the dwellings
of ants. Nature has not been very generous on its behalf. It is blind,
and its eyes are indeed altogether atrophied. The elytra are soldered
at the median edge, so that it cannot spread its wings to fly. It is
an animal predestined to the yoke; and for the rest its masters treat
it with extreme kindness. The yellow ants, according to Mueller,[64]
have reduced this outcast beetle to domesticity, and it is almost a
piece of good fortune for him to have lost his freedom and to have
gained in exchange a shelter and a well-furnished trough. These
insects are in fact cared for by their masters, who feed them by
disgorging into their mouths the sweet liquids they have gathered here
and there. If a nest is disturbed the ants hasten to carry their eggs
and larvae out of danger; they display the same solicitude with regard
to the _Claviger_, and carefully bear them to the depth of their
galleries. It must not be believed that the practical insect takes so
much care in order to repair the injustice of nature towards the
beetle; the part of a devoted sick nurse would not suit him; he cares
for the _Claviger_ because it is his property, a capital which brings
in interest in the shape of excellent sweet little drops which are
good to suck.[65]
[64] Ph. W. J. Mueller, "Beitraege zur Naturgeschichte der
Gattung _Claviger_," _Germer u. Zincken's Magaz. d.
Entomol._, iii., 1881, pp. 69-112.
[65] There is little doubt, however, that some species of
Aphides and allied Coccidae would be liable to extermination
if not protected by their ant masters. See, for instance,
Forel, _Bull. Soc. Vaud._, 1876. Mr. Cockerell in Jamaica
has noted an interesting Coccid, _Icerya rosae_, which is
protected by ants; "at the present moment some of these
_Iceryae_ are enjoying life, which would certainly have
perished at my hands but for the inconvenience presented by
the numbers of stinging ants."--_Nature_, 27th April 1893.
Mr. Romanes (_Nature_, 18th May 1893) quotes as follows from
a letter addressed to him by the Rev. W. G. Proudfoot:--"On
looking up I noticed that hundreds of large black ants were
going up and down the tree, and then I saw the aphides....
But what struck me most was that the aphides showered down
their excretions independently of the ants' solicitations,
while at other times I noticed that an ant would approach an
aphis without getting anything, and would then go to
another. I was struck with this, because I remembered Mr.
Darwin's inability to make the aphides yield their secretion
after many experiments. A large number of hornets were
flying about the tree, but seemed afraid of the ants; for
when they attempted to alight, an ant would at once rush to
the spot, and the hornet would get out of its way."
A yellow ant, who wishes to enjoy the result of the cares given to his
pensioner, approaches it and gently caresses it with his antennae; the
other shows signs of pleasure at this visit, and soon a pearly drop
appears on the tuft of hairs at the edge of its elytra, and this the
ant hastens to lick. The beetle is thus exploited and tickled by all
the members of the community to which he belongs who meet him on their
road. But when it has been milked two or three times it ceases to
secrete. A solicitous ant arriving at this moment finds its efforts in
vain, but still behaves like a good shepherd; it shows no impatience
or anger towards its exhausted beast, knowing well that it is only
necessary to come back a little later or to go to another member of
the herd. Nor are his cares lessened by finding the source dried up.
He foresees that it will still be good after repose, and if it is
hungry he disgorges food for it.
_Degrees of civilisation in the same species of Ants._--These facts
are sufficiently marvellous in themselves, but are more surprising
when we recollect that they cannot be regarded as an innate and
unreflecting instinct with which all the individuals of the same
species are endowed. The art of domesticating the _Claviger_ is a
stage of civilisation reached by some tribes and not by others.
Lespes[66] has placed this out of doubt in the following manner. He
had specimens of _Lasius niger_ who exploited a flock of Coleoptera.
Having met ants of the same species who possessed no flocks, he
brought them some. At the sight of the little insects they threw
themselves on them, killed them, and devoured them. If we compare
these facts with those which pass in human societies, it will seem to
us that these latter Hymenoptera behave like a horde of hunters in the
presence of a flock of sheep, while the first have already arrived at
the sheep-herding stage.
[66] "Recherches sur quelques Coleopteres aveugles," _Ann.
Sc. Nat._, v. Serie, t. ix., 1868, p. 71.
_Aphis-pens and paddocks._--Ants can also keep Aphides in their homes.
In this case, fearing that the adult beasts may not be able to adopt a
change of surroundings and food, they bring the eggs to their nests
and care for them at the same time as their own children. In time they
come out and constitute a flock easy to tame. Other ants, still more
intelligent, have discovered a method of holding the Aphides captive,
while allowing them to enjoy their accustomed life, and to feed at
will on the foods they prefer on their own favourite spots. It is
sufficient for this purpose to establish barriers around a group of
cattle who have themselves fixed the place of their sojourn. The
_Lasius niger_, a skilful architect, constructs vaulted passages from
his dwelling into the country. These covered roads, built with earth
moistened with saliva, have various ends; some have been made in order
to reach remote work sheltered from the sun, or to give concealment
from enemies. Many lead to the pens of the Aphides; they reach from
the anthill as far as the foot of a plant where these insects are
abundant. In order to have their milkers at their disposal, without
removing them from pasture, the ants make tunnels along the stalk, and
enclose within it all the Aphides they meet. They thus prevent any
desire for a distant ramble. But in order that the flock may not be
too closely confined, the _Lasius niger_ enlarge the galleries in
places, and make a sort of chamber or stable in which the beasts may
disport themselves at ease. These halls, which are proportionately
very vast, are supported against the branches and leaves of the plant
which bears up the walls and the vaults. The captives find themselves
then with all the advantages of material life, and may be milked with
every facility.[67]
[67] P. Huber, _Recherches sur les Moeurs des Fourmis
indigenes_, pp. 176-200.
An allied species of ant, the _Lasius brunneus_, lives almost entirely
on the sweet secretion of large Aphides in the bark of oaks and walnut
trees. The ants construct around these insects cabins made of
fragments of wood, and wall them in completely so as to keep them at
their own disposal.
The _Myrmica_ also forms similar pasture lands; its system is rather
less perfect than that of the _Lasius_, as it does not form covered
galleries to reach its stables. It is content to build large earth
huts around a colony. A large hole, which allows the passage of the
ants, but not the escape of the flock, is formed so that they may come
to milk their cows. They use the same methods we have seen practised
on the _Claviger_, caressing the insect with their antennae until the
sugared drop appears.[68]
[68] In Central America, Belt has described how the
Leaf-hoppers are milked for their honey by various species
of Ants, and also by a Wasp. He considered that some species
of Leaf-hopper would be exterminated if it were not for the
protection they received from Ants.--_Naturalist in
Nicaragua_, 1888, pp. 227-230.
An example is quoted which shows still greater intelligence and
foresight in Ants. They have been known to repopulate their
territories after an epidemic, or at least after the destruction of
their Aphides. The proprietor of a tree, finding it covered with these
exploited beasts, cleared it of its inconvenient guests by repeated
washes; but the dispossessed Hymenoptera, considering that this
pasture close to their nest was very convenient for a flock, resolved
to repopulate it, and for some time these tenacious insects could be
seen bringing back among the foliage Aphides captured elsewhere.[69]
[69] P. Huber, _Recherches_, etc., pp. 210-250; Lubbock, "On
the Habits of Ants," _Wiltshire Arch. and Nat. Hist. Mag._,
1879, pp. 49-62.
_Slavery among Ants._--The custom of making slaves is widely spread in
the ant world; I have already described the expeditions organised to
obtain them. We will now consider the relations of these insects among
themselves.
The _Formica sanguinea_ takes possession of the eggs of the _Formica
fusca_ and rears them with its own. When the slaves reach the adult
condition they live beside their masters and share their labours, for
the latter work, are skilful in all tasks, and can by their own
activity construct an ant-hill and keep it going. If they desire
servants, it is not in order to throw all the work on them, but to
have intelligent assistants. This is the primitive form of slavery as
it first existed among men. It was not until later that it became
modified, to become at last an institution against which the sentiment
of justice arose. Other species of Ants have pushed the exploitation
of slaves to a point Man has never reached. But the _Formica
sanguinea_ are companions to their helpers rather than masters, and
even show them great consideration. When the colony emigrates one may
see the owners of the nest, who are of larger size than the _Formica
fusca_, take these up in their jaws and carry them the entire way.
The Amazons (_Polyergus rufescens_) act otherwise. Very skilful in
obtaining slaves and powerfully armed for triumphant raids, their
nests always contain legions of servants, and the custom of being
waited upon has become so impressed on the race by heredity that it is
an instinct stronger even than personal preservation. The master ant
has not only lost the taste and the idea of work, but even the habit
of feeding himself, and would die of hunger beside a pile of honey or
sugar if a grey ant was not there to put it into his mouth. Thus
Huber, the earliest accurate observer of these ants, enclosed thirty
Amazons with several pupae and larvae of their own species, and twenty
negro pupae, in a glass box, the bottom of which was covered with a
thick layer of earth; honey was given to them, so that, although cut
off from their auxiliaries, the Amazons had both shelter and food. At
first they appeared to pay some little attention to the young; this
soon ceased, and they neither traced out a dwelling nor took any food;
in two days one-half died of hunger, and the other remained weak and
languid. Commiserating their condition, he gave them _one_ of their
black companions. This little creature, unassisted, formed a chamber
in the earth, gathered together the larvae, put everything into
complete order, and preserved the lives of those which were about to
perish.
All their industry is expended in the acquisition of captives. The
_Polyergus_ avoid introducing into their houses adults who would not
become reconciled to the loss of liberty, and would prefer to die
rather than work for others. They carry off the larvae of _Formica
fusca_ and _Formica cunicularia_. When brought into the ant-hill these
larvae are placed in the jaws of slaves of their own species, who care
for them; they are born captives, and have neither the regret nor the
idea of a free life. Among the Amazons the slaves undertake every
labour; it is they who build and who care for the larvae of their
masters, as well as those carried away in expeditions. They have also
complicated personal services towards the _Polyergus_. They bring them
food, lick off the dust from their hairs, clean them, carry them from
one place to another, if there is need to emigrate, although they
themselves are much smaller. The masters, by force of losing interest
in work, lose also their votes when it is a question of taking a
resolution concerning the whole colony. The servants act on their own
initiative and their own responsibility, direct constructions
according to their own ideas, and even in grave concerns, such as
emigration, the idle masters do not seem to be consulted. The workers
deliberate among themselves, and having come to a decision, proceed to
execute it. They transport the household goods, the eggs, the future
of the city, and the Amazons who have become its parasites. It is a
most curious fact that the slaves should submit to this precarious
fate when their masters are absolutely dependent on them. It is just
to add that the robust mandibles of the latter may contribute to
preserve the position they enjoy.[70]
[70] Lubbock has a brief discussion on the relations of Ants
to their domestic animals and to their slaves, _Ants, Bees,
and Wasps_, chap. iv.