CHAPTER 6. THE BURYING-BEETLES: EXPERIMENTS.

Let us proceed to the rational prowess which has earned for the Necrophorus the better part of his renown and, to begin with, let us submit the case related by Clairville--that of the too hard soil and the call for assistance--to experimental test.

With this object in view, I pave the centre of the space beneath the cover, level with the soil, with a brick and sprinkle the latter with a thin layer of sand. This will be the soil in which digging is impracticable. All about it, for some distance and on the same level, spreads the loose soil, which is easy to dig.

In order to approximate to the conditions of the little story, I must have a Mouse; with a Mole, a heavy mass, the work of removal would perhaps present too much difficulty. To obtain the Mouse I place my friends and neighbours under requisition; they laugh at my whim but none the less proffer their traps. Yet, the moment a Mouse is needed, that very common animal becomes rare. Braving decorum in his speech, which follows the Latin of his ancestors, the Provençal says, but even more crudely than in my translation: "If you look for dung, the Asses become constipated!"

At last I possess the Mouse of my dreams! She comes to me from that refuge, furnished with a truss of straw, in which official charity gives the hospitality of a day to the beggar wandering over the face of the fertile earth; from that municipal hostel whence one invariably emerges verminous. O Réaumur, who used to invite marquises to see your caterpillars change their skins, what would you have said of a future disciple conversant with such wretchedness as this? Perhaps it is well that we should not be ignorant of it, so that we may take compassion on the sufferings of beasts.

The Mouse so greatly desired is mine. I place her upon the centre of the brick. The grave-diggers under the wire cover are now seven in number, of whom three are females. All have gone to earth: some are inactive, close to the surface; the rest are busy in their crypts. The presence of the fresh corpse is promptly perceived. About seven o'clock in the morning, three Necrophori hurry up, two males and a female. They slip under the Mouse, who moves in jerks, a sign of the efforts of the burying-party. An attempt is made to dig into the layer of sand which hides the brick, so that a bank of sand accumulates about the body.

For a couple of hours the jerks continue without results. I profit by the circumstance to investigate the manner in which the work is performed. The bare brick allows me to see what the excavated soil concealed from me. If it is necessary to move the body, the Beetle turns over; with his six claws he grips the hair of the dead animal, props himself upon his back and pushes, making a lever of his head and the tip of his abdomen. If digging is required, he resumes the normal position. So, turn and turn about, the sexton strives, now with his claws in the air, when it is a question of shifting the body or dragging it lower down; now with his feet on the ground, when it is necessary to deepen the grave.

The point at which the Mouse lies is finally recognized as unassailable. A male appears in the open. He explores the specimen, goes the round of it, scratches a little at random. He goes back; and immediately the body rocks. Is he advising his collaborators of what he has discovered? Is he arranging matters with a view to their establishing themselves elsewhere, on propitious soil?

The facts are far from confirming this idea. When he shakes the body, the others imitate him and push, but without combining their efforts in a given direction, for, after advancing a little towards the edge of the brick, the burden goes back again, returning to the point of departure. In the absence of any concerted understanding, their efforts of leverage are wasted. Nearly three hours are occupied by oscillations which mutually annul one another. The Mouse does not cross the little sand-hill heaped about it by the rakes of the workers.

For the second time a male emerges and makes a round of exploration. A bore is made in workable earth, close beside the brick. This is a trial excavation, to reveal the nature of the soil; a narrow well, of no great depth, into which the insect plunges to half its length. The well-sinker returns to the other workers, who arch their backs, and the load progresses a finger's-breadth towards the point recognized as favourable. Have they done the trick this time? No, for after a while the Mouse recoils. No progress towards a solution of the difficulty.

Now two males come out in search of information, each of his own accord. Instead of stopping at the point already sounded, a point most judiciously chosen, it seemed, on account of its proximity, which would save laborious transportation, they precipitately scour the whole area of the cage, sounding the soil on this side and on that and ploughing superficial furrows in it. They get as far from the brick as the limits of the enclosure permit.

They dig, by preference, against the base of the cover; here they make several borings, without any reason, so far as I can see, the bed of soil being everywhere equally assailable away from the brick; the first point sounded is abandoned for a second, which is rejected in its turn. A third and a fourth are tried; then another and yet another. At the sixth point the selection is made. In all these cases the excavation is by no means a grave destined to receive the Mouse, but a mere trial boring, of inconsiderable depth, its diameter being that of the digger's body.

A return is made to the Mouse, who suddenly quivers, oscillates, advances, recoils, first in one direction, then in another, until in the end the little hillock of sand is crossed. Now we are free of the brick and on excellent soil. Little by little the load advances. This is no cartage by a team hauling in the open, but a jerky displacement, the work of invisible levers. The body seems to move of its own accord.

This time, after so many hesitations, their efforts are concerted; at all events, the load reaches the region sounded far more rapidly than I expected. Then begins the burial, according to the usual method. It is one o'clock. The Necrophori have allowed the hour-hand of the clock to go half round the dial while verifying the condition of the surrounding spots and displacing the Mouse.

In this experiment it appears at the outset that the males play a major part in the affairs of the household. Better-equipped, perhaps, than their mates, they make investigations when a difficulty occurs; they inspect the soil, recognize whence the check arises and choose the point at which the grave shall be made. In the lengthy experiment of the brick, the two males alone explored the surroundings and set to work to solve the difficulty. Confiding in their assistance, the female, motionless beneath the Mouse, awaited the result of their investigations. The tests which are to follow will confirm the merits of these valiant auxiliaries.