I need not here repeat what I have said in a former letter concerning the exemplary attention paid by these kind foster-mothers to the young brood of their colonies; nor shall I enlarge upon the building and nature of their habitations, which have been already noticed[65]:—but, without either of these, I have matter enough to fill the rest of this letter with interesting traits, while I endeavour to teach you their language, to develop their affections and passions, and to delineate their virtues;—while I show them to you when engaged in war, and enable you to accompany them both in their military expeditions and in their emigrations,—while I make you a witness of their indefatigable industry and incessant labours,—or invite you to be present, during their hours of relaxation, at their sports and amusements.
That ants, though they are mute animals, have the means of communicating to each other information of various occurrences, and use a kind of language which is mutually understood, will appear evident from the following facts.
If those at the surface of a nest are alarmed, it is wonderful in how short a time the alarm spreads through the whole nest. It runs from quarter to quarter; the greatest inquietude seems to possess the community; and they carry with all possible dispatch their treasures, the larvæ and pupæ, down to the lowest apartments. Amongst those species of ants that do not go much from home, sentinels seem to be stationed at the avenues of their city. Disturbing once the little heaps of earth thrown up at the entrances into the nest of F. flava, which is of this description, I was struck by observing a single ant immediately come out, as if to see what was the matter, and this three separate times.
The F. herculanea inhabits the trunks of hollow trees on the continent, for it has not yet been found in England, upon which they are often passing to and fro. M. Huber observed, that when he disturbed those that were at the greatest distance from the rest, they ran towards them, and, striking their head against them, communicated their cause of fear or anger,—that these, in their turn, conveyed in the same way the intelligence to others, till the whole colony was in a ferment, those neuters which were within the tree running out in crowds to join their companions in the defence of their habitation. The same signals that excited the courage of the neuters produced fear in the males and females, which, as soon as the news of the danger was thus communicated to them, retreated into the tree as to an asylum.
The legs of one of this gentleman's artificial formicaries were plunged into pans of water, to prevent the escape of the ants;—this proved a source of great enjoyment to these little beings, for they are a very thirsty race, and lap water like dogs[66]. One day, when he observed many of them tippling very merrily, he was so cruel as to disturb them, which sent most of the ants in a fright to the nest; but some more thirsty than the rest continued their potations. Upon this, one of those that had retreated returns to inform his thoughtless companions of their danger; one he pushes with his jaws; another he strikes first upon the belly, and then upon the breast; and so obliges three of them to leave off their carousing, and march homewards; but the fourth, more resolute to drink it out, is not to be discomfited, and pays not the least regard to the kind blows with which his compeer, solicitous for his safety, repeatedly belabours him:—at length, determined to have his way, he seizes him by one of his hind-legs, and gives him a violent pull:—upon this, leaving his liquor, the loiterer turns round, and opening his threatening jaws with every appearance of anger, goes very coolly to drinking again; but his monitor, without further ceremony, rushing before him, seizes him by his jaws, and at last drags him off in triumph to the formicary[67].
The language of ants, however, is not confined merely to giving intelligence of the approach or presence of danger; it is also co-extensive with all their other occasions for communicating their ideas to each other.
Some, whose extraordinary history I shall soon relate to you, engage in military expeditions, and often previously send out spies to collect information. These, as soon as they return from exploring the vicinity, enter the nest; upon which, as if they had communicated their intelligence, the army immediately assembles in the suburbs of their city, and begins its march towards that quarter whence the spies had arrived. Upon the march, communications are perpetually making between the van and the rear; and when arrived at the camp of the enemy, and the battle begins, if necessary, couriers are dispatched to the formicary for reinforcements[68].
If you scatter the ruins of an ant's nest in your apartment, you will be furnished with another proof of their language. The ants will take a thousand different paths, each going by itself, to increase the chance of discovery; they will meet and cross each other in all directions, and perhaps will wander long before they can find a spot convenient for their reunion. No sooner does any one discover a little chink in the floor, through which it can pass below, than it returns to its companions, and, by means of certain motions of its antennæ, makes some of them comprehend what route they are to pursue to find it, sometimes even accompanying them to the spot; these, in their turn, become the guides of others, till all know which way to direct their steps[69].
It is well known also, that ants give each other information when they have discovered any store of provision. Bradley relates a striking instance of this. A nest of ants in a nobleman's garden discovered a closet, many yards within the house, in which conserves were kept, which they constantly attended till the nest was destroyed. Some in their rambles must have first discovered this depôt of sweets, and informed the rest of it. It is remarkable that they always went to it by the same track, scarcely varying an inch from it, though they had to pass through two apartments; nor could the sweeping and cleaning of the rooms discomfit them, or cause them to pursue a different route[70].
Here may be related a very amusing experiment of Gould's. Having deposited several colonies of ants (F. fusca) in flower-pots, he placed them in some earthen pans full of water, which prevented then from making excursions from their nest. When they had been accustomed some days to this imprisonment, he fastened small threads to the upper part of the pots, and extending them over the water pans fixed them in the ground. The sagacious ants soon found out that by these bridges they could escape from their moated castle. The discovery was communicated to the whole society, and in a short time the threads were filled with trains of busy workers passing to and fro[71].