To receive the shock it is necessary that the creature, whatever it may be—in most cases, probably, a fish—should touch the eel’s body in two places, for otherwise the electric circuit will not be completed, and there will be no discharge. Merely to poke the eel, therefore, with one finger would do one no harm, whereas to catch hold of a large one might even cause death. Yet in spite of the dangerous power it possesses, the torpedo is eaten by the natives of the countries in which it is found, for it is fat and succulent, and its electric battery, if once it can be got rid of, does not affect its taste, which is excellent. Once caught, this is not a difficult thing to do. It can be cut out, though care must be taken in the way above-mentioned, since the shock can be communicated not only by a direct seizure of the creature, but indirectly through any connecting substance held in the hand. But how are the eels to be caught? The method employed by the Indians is to make them exhaust their batteries by delivering a series of shocks, after which they remain for a long time innocuous, till re-stored with the electric energy. When, therefore, any large shallow pool is discovered, in which gymnoti are likely to be lying—such being often produced by the overflowing of rivers and subsequent withdrawal of their waters—a troop of half-wild horses are collected about it, and then, with cries and blows, urged to enter. A wild and horrible scene of confusion instantly ensues. The alarmed eels dart hither and thither amongst the legs of the horses, discharging their batteries, and the horses, when struck, leap into the air, and, if the shock has been violent, fall down stunned, amongst the rest. Others, less injured, but mad with pain and terror, lash out with their heels, or gallop wildly about, no longer avoiding their fellows, and seeming to have lost the sense of direction. Dashing together, one horse is flung down by another—others fall over them—they lie struggling in heaps. Many break back, or reach the further shore, but each time that they do so, and strive to leave the pool, they are driven into it again by the Indians, and shock after shock continues to be poured in amongst them. Each one, however, is weaker than the last, till, at length, no more effect is produced, and the scene, though still wild and disorderly, becomes partially relieved of its horrors. Then, and not till then, are the terrified animals—all those, that is to say, that are capable of doing so—allowed to leave their inferno, after which the Indians enter it, and secure the now powerless eels, many of which have been more or less injured by the trampling of the horses’ hoofs. Such is the account given by Humboldt, which was given to him by the Indians. It is right to add that it has not yet been confirmed, so that many now hold it to be untrue, and think that the great naturalist and traveller must have been imposed upon. One professor, who writes very learnedly of the gymnotus, and other electric fishes—for there are some other ones—is so sure of this, that he thinks it high time this story of Humboldt’s were forgotten. Well, I tried to forget it, but I found it was too picturesque. So I have remembered it, and forgotten the professor’s own treatise, instead—which was much the easier thing to do.
CHAPTER XII
PROTECTIVE RESEMBLANCE IN NATURE—SPIDERS THAT LOOK LIKE ANTS—A TRAP TO CATCH A BUTTERFLY—FALSE DEVOTEES—LEAF, STICK, AND GRASS-RESEMBLING INSECTS—“CUCULLUS NON FACIT MONACHUM.”
In previous chapters we have seen how spiders are preyed upon in a peculiar way, and for a special purpose, by various species of wasps, and how, in a more general manner, they fall victims to ants. There are spiders, however, who escape both wasps and ants, as well as other enemies, against which they are not strong enough to contend, not by running away, merely, or concealing themselves, which are ordinary methods, but by another plan not quite so common in nature, which some people think is only resorted to by ourselves. We, for instance, if we have committed a robbery or anything of that sort, and it is known that we did it, disguise ourselves like somebody else—it does not matter who—so as to get to Spain or America, or anywhere we think best, without being recognised. Or sometimes we do the disguising first, and get the money in that way, dressing up to resemble some person that we pretend to be, or someone in his or her class of life—the nobility mostly—and living in the way that they would do, so that we take people in right and left, and they trust us in a way that they would never think of doing if they knew that we were only poor, honest people who paid our way, and made no sort of dash or show. Now this is just what some animals, especially insects, do, only whereas we have to dress up for each occasion, and can assume different disguises, they are always disguised in the same way, and whereas we know what we are doing, and why we are doing it, they know nothing at all about it, which last gives them a great advantage, since even the finest acting does not quite come up to nature. Some creatures, in fact, are cheats all their lives through. Their “whole life is a lie,” as one of the characters in one of Scott’s novels said once, a long time ago, and as thousands of very different sorts of characters in very different kinds of novels, have been saying to or of one another or themselves—or words to that effect—ever since.
And now for examples, which is the only way of getting to understand anything, unless it is very simple indeed. To begin with spiders. There are some that look exactly like ants, so that anyone seeing them for the first time would think that they were ants, and would only find out that they were not, but spiders, by degrees, and perhaps not at all if he were not something of an entomologist. Ants, like all other insects, have six legs, whereas spiders, which are not insects at all, have eight. But the spider, by holding up one of its anterior pair of legs, either the first or the second pair, and bending or pointing them to suit the kind of ant it resembles, makes them look like a pair of antennæ, springing not from its body but from the head. The head itself looks much more like an ant’s than a spider’s, and this is still more—or still more remarkably—the case with the body, which is lengthened in various degrees, and shaped in various ways, in accordance with that of the model on which the make-up is founded.
But this is not all, or enough. However much the spider might look like the ants that it lived amongst, yet if it did not move in the same kind of way that they do it would be detected, and in consequence devoured. Spiders do not walk or run about like ants, not, that is to say, with the same sort of mannerisms that they have. Some of them jump, which is a thing that ants never do, and all ants, when in search of booty, move in a funny little zigzagging way from side to side, which gives them a greater chance of finding things than they would have by going straight forward. Now it is just in this way that some of these ant-like spiders habitually walk, and they do not jump any more than the ants themselves, even though they may happen to belong to a family of jumping spiders. Again, when they eat anything, instead of sitting still, to do it, which is what spiders generally do, they keep pulling the morsel, which is generally some live thing, about, as though to divide it into parts, to be carried to the nest separately, which is what ants often do; and all the while they keep moving the two legs which look like a pair of antennæ just in the way in which it is proper for antennæ to move, sometimes tapping their prey with them, and at other times waving them about. No wonder then that the ants are taken in, for, to the boot of all these resemblances, the spider is of the same size and colour as themselves. The result of it all is, of course, that not an ant of them ever thinks of molesting the spider. He would be a nice tasty morsel for them if they only knew it, and as he is soft and they are hard, they would have no difficulty in overcoming him, even if it were only one to one, instead of one to twenty or more. But as they only see one of themselves running about—and, for my part, I think the spider must feel like an ant, as well as look like one—it never enters their head to attack him, or even not to be polite, for ants of the same nest are very polite to one another.
But here all sorts of questions arise, which, as far as I know, have not yet been answered, and I think that the ways of these spiders ought to be more closely observed. Ants of the same nest, indeed, are quite friendly one with another, but this is not the case if they belong to different nests, whilst there is nothing but hostility, as a rule, between ants of different species. Moreover, one ant can always tell, by some means which we do not yet quite understand, whether another one belongs to its own community or not, and if it does not there is generally a fight between them, unless one of the two runs away. It would seem, therefore, as if, for its disguise to be of much use to the spider, it would have to keep not only with one species, but with one special community of ants, and even then it ought to be found out, unless it lives with them as a parasite in their nest, as some insects and other creatures do. Is this the case, or does the spider take care not to come into actual contact with the ants, so that just by looking like one at a little distance, it is left alone? But, even so, it would be only one species of ant that would be inclined to let him alone, and as other species would be hostile to the one he resembled, one can imagine inconveniences as well as benefits arising through the disguise. For the above reasons I think it would be very interesting to find out a little more about the habits of these ant-resembling spiders. Of course if they preyed upon the ants they resembled, the thing would be easy to understand. But this, as has already been said or implied, is not the case.
Other kinds of spiders are protected in the same way by resembling different kinds of things, which are not good to eat, and as, in this way, they are saved not only from ants, but from all sorts of other creatures, as well,—from all those, for instance, that prey upon ants—this seems to me a much better kind of disguise. One of these spiders lives in Madagascar, and has the most peculiar-shaped body that one can imagine. At the top it runs up into a sort of pyramid, starting from a rounded base and being higher at one side than another, whilst round about it there are several smaller pyramids, or spikey protuberances, quite babies compared to the large one. On a table, perhaps, or in that horrid thing, a cabinet, it might be difficult to say what this spider was intended to look like, but when it sits motionless, according to its habit, on the branch of a tree, it is impossible to distinguish it from one of those woody knots which often form themselves on the bark, and which the eye rests on without particularly noticing. Another kind, common in Wisconsin, lives upon the cedar trees, which are a common feature—and a very picturesque one—of the country. They are covered with lichens, and so much does this spider, in its coloration and markings, resemble a lichen, itself, that when it sits still amongst them the eye is unable to pick it out from its surroundings.
But all this is as nothing compared to a Javanese spider, the whole of whose energies seem bent to make itself into a living facsimile of so mean an object as a bird-dropping. To do this, it lies on its back upon a leaf, over some part of which it has previously spread a film-like web, which itself plays a part in the deception. “Such excreta,” says Mr. Fobes, the discoverer of this wonderful spider, and who was, himself, taken in by it, “consist of a central and denser portion of a pure white chalk-like colour streaked, here and there, with black and surrounded by a thin border of the dried-up, more fluid part.” The filmy web spread irregularly over the leaf, presents this latter appearance, whilst the spider itself, having a chalky-white abdomen and black legs, which, as it lies, are crossed over it, exactly resembles the solid mass in the centre of it. In the previous cases that we have been considering, the resemblance is of a protective nature—this, at least, is what seems more specially aimed at—but here the design is darker and deeper. Many butterflies—creatures typical of beauty generally—as if resolved to carry on the allegory, are accustomed to feed upon ordure. One of them, fluttering through the leaves of the tropical forest, perceives, as she thinks, a rich banquet spread out before her, and descending, in all her radiant and ethereal beauty, to enjoy it, is caught and feasted on herself.