The Wonders of Instinct: Chapters in the Psychology of Insects

by Jean-Henri Fabre

Yet another of the fine arguments in favour of the reasoning power of animals flies from the light of investigation and founders in the slough of error! I admire your simple faith, you masters who take seriously the statements of chance-met observers, richer in imagination than in veracity; I admire your credulous zeal, when, without criticism, you build up your theories on such absurdities.

Let us proceed. The stake is henceforth planted vertically, but the body hanging on it does not reach the base: a condition which suffices to ensure that there is never any digging at this point. I make use of a Mouse, who, by reason of her trifling weight, will lend herself better to the insect's manoeuvres. The dead body is fixed by the hind-legs to the top of the stake with a ligature of raphia. It hangs plumb, in contact with the stick.

Very soon two Necrophori have discovered the tit-bit. They climb up the miniature mast; they explore the body, dividing its fur by thrusts of the head. It is recognized to be an excellent find. So to work. Here we have again, but under far more difficult conditions, the tactics employed when it was necessary to displace the unfavourably situated body: the two collaborators slip between the Mouse and the stake, when, taking a grip of the latter and exerting a leverage with their backs, they jerk and shake the body, which oscillates, twirls about, swings away from the stake and relapses. All the morning is passed in vain attempts, interrupted by explorations on the animal's body.

In the afternoon the cause of the check is at last recognized; not very clearly, for in the first place the two obstinate riflers of the gallows attack the hind-legs of the Mouse, a little below the ligature. They strip them bare, flay them and cut away the flesh about the heel. They have reached the bone, when one of them finds the raphia beneath his mandibles. This, to him, is a familiar thing, representing the gramineous fibre so frequent in the case of burial in grass-covered soil. Tenaciously the shears gnaw at the bond; the vegetable fetter is severed and the Mouse falls, to be buried a little later.

If it were isolated, this severance of the suspending tie would be a magnificent performance; but considered in connection with the sum of the Beetle's customary labours it loses all far-reaching significance. Before attacking the ligature, which was not concealed in any way, the insect exerted itself for a whole morning in shaking the body, its usual method. Finally, finding the cord, it severed it, as it would have severed a ligament of couch-grass encountered underground.

Under the conditions devised for the Beetle, the use of the shears is the indispensable complement of the use of the shovel; and the modicum of discernment at his disposal is enough to inform him when the blades of his shears will be useful. He cuts what embarrasses him with no more exercise of reason than he displays when placing the corpse underground. So little does he grasp the connection between cause and effect that he strives to break the bone of the leg before gnawing at the bast which is knotted close beside him. The difficult task is attacked before the extremely simple.

Difficult, yes, but not impossible, provided that the Mouse be young. I begin again with a ligature of iron wire, on which the shears of the insect can obtain no purchase, and a tender Mouselet, half the size of an adult. This time a tibia is gnawed through, cut in two by the Beetle's mandibles near the spring of the heel. The detached member leaves plenty of space for the other, which readily slips from the metallic band; and the little body falls to the ground.

But, if the bone be too hard, if the body suspended be that of a Mole, an adult Mouse, or a Sparrow, the wire ligament opposes an insurmountable obstacle to the attempts of the Necrophori, who, for nearly a week, work at the hanging body, partly stripping it of fur or feather and dishevelling it until it forms a lamentable object, and at last abandon it, when desiccation sets in. A last resource, however, remains, one as rational as infallible. It is to overthrow the stake. Of course, not one dreams of doing so.

For the last time let us change our artifices. The top of the gibbet consists of a little fork, with the prongs widely opened and measuring barely two-fifths of an inch in length. With a thread of hemp, less easily attacked than a strip of raphia, I bind together, a little above the heels, the hind-legs of an adult Mouse; and between the legs I slip one of the prongs of the fork. To make the body fall it is enough to slide it a little way upwards; it is like a young Rabbit hanging in the front of a poulterer's shop.

Five Necrophori come to inspect my preparations. After a great deal of futile shaking, the tibiae are attacked. This, it seems, is the method usually employed when the body is retained by one of its limbs in some narrow fork of a low-growing plant. While trying to saw through the bone—a heavy job this time—one of the workers slips between the shackled limbs. So situated, he feels against his back the furry touch of the Mouse. Nothing more is needed to arouse his propensity to thrust with his back. With a few heaves of the lever the thing is done; the Mouse rises a little, slides over the supporting peg and falls to the ground.