BATS

The bat was formerly looked upon as an uncanny sort of bird, and described as such in the old natural histories. Oh, those ever delightful old natural histories, and the vision of the wise old naturalist examining a recently-taken specimen through his horn-bound spectacles, and setting it gravely down in his books that it is the only known bird which was clothed in fur in place of feathers! Or, as Plinius puts it, the only bird which brings forth and suckles its young, just as we say that the Australian water-mole is the only mammal which lays eggs. The modern ornithologist will have nothing to do with the creature; but after his expulsion from the feathered nation it was his singular good fortune not to sink lower in the scale; he was, on the contrary, raised to the mammalians, or quadrupeds, as our fathers called them; then on the discovery being made that he was anatomically related to the lemurs, he was eventually allotted a place in our systems next after that ancient order of fox-faced monkeys. And thus it has come to pass that when some one writes a book on the mammals of this island, which has no monkeys or lemurs, and man cannot be included in such works on account of an old convention or prejudice, he is obliged to give the proud first place to this very poor relation.

It is his misfortune, since it would have been more agreeable to the general reader if he could have led off with some imposing beast--the extinct wolf or tusky wild boar, for example--or, better still, with the white cattle of Chillingham, or the roaring stag with his grand antlers. The last is an undoubted survival, one which, encountered in some incult place where it is absolutely free and wild, moves us to a strange joy--an inherited memory and a vision of a savage, prehistoric land of which we are truer natives than we can ever be of this smooth sophisticated England. The science of zoology could not have it so, since it does not and cannot take man and his mental attitude towards other forms of life into account--cannot consider the fact that he is himself an animal of prey, several feet high, with large eyes fitted to look at large objects, and that he measures and classifies all creatures by an instinctive rule and standard, mentally pitting his strength and ferocity against theirs. What a discrepancy, then, between things as seen by the natural man and as they appear in our scientific systems, which make the small negligible bat the leader of the procession of British beasts--even this repulsive little rearmouse, or flittermouse, that flits from his evil-smelling cranny, in appearance a misshapen insect of unusual size, to pursue his crooked, broken-boned, squeaky flight in the obscurity of evening.

Imagine the effect of this modern rearrangement of the mammals on the mammals if they knew! The white bull of Chillingham would shake his frowning front and the stag his branching antlers in scorn; the wolf, in spite of being extinct, would howl; the British seal bark; the wild cat snarl, and the badger make free use of his most underground expressions of rage at such an insult; rabbit and hare would exchange looks of astonishment and apprehension; the hedgehog would roll himself into a ball with disgust; the mole sink back into his run; the fox smile sardonically; and the whole concourse, turning their backs on the contemptible leader thrust on them, would march off in the opposite direction.

Now the imaginary case of these beasts offended in their dignity fairly represents that of humanity angry at the intolerable insult implied in the Darwinian notion. But we have now so far outgrown that feeling that it is no longer an offence for the zoologist to tell us not only that we are related to the lemur with its luminous opalescent or topaz eyes, that are like the eyes of angels and are instinct with a mysterious intelligence when they look at us with a strange friendliness in them as if they knew what we, after thousands of years of thinking, have only just found out--not only that this animal is our relation, but even such a creature as the bat!

Look on this picture, and on this! On the eyes, for instance, of these two beasts, and we see at once that the bat is an example of extreme degeneration; also that it is the most striking example in the animal world of a degenerate in which the downward process has at length been arrested, and instead of extinction a new, different, and probably infinitely longer life given to it.

We are reminded of the flea--the remote descendant, as we deem, of a gilded fly that was once free of the air and feasted at the same sunlit flowery table with bright-winged butterflies and noble wasps and bees.

There are those who have doubts about this genealogical tree of the bat, and would have it that he is an insectivore related to moles, shrews, and such-like low-down animals, but the main facts all point the other way. And we may assume that the bat--our familiar flittermouse, since we are not concerned with the somewhat different frugivorous bats of the tropics--is the remote descendant of a small degenerate lemur that inhabited the upper branches of high trees in the African forest; that he became exclusively insectivorous and developed an extreme activity in capturing his winged prey, and was in fact like the existing small lemur, the golago, which in pursuing insects “seems literally to fly through the air,” as Sir H. Johnston has said. Finally, there was the further development, the ovidean metamorphosis, when the loose expanding membrane of the hands and arms and sides grew to wings.

But albeit like a bird in its faculty of flight, the bat was a mammal still, and was rather like a badly constructed flying-machine, at best an improvement on the parachute. This then was a risky experiment on Nature’s part, seeing that to launch a mammal on the air is to put it into competition with birds, and throw it in the way of its rapacious bird enemies, natives of that element and infinitely its superior in flying powers. But Nature, we see, takes risks of this kind with a very light heart; her busy brain teems with thousands, millions, of inventions, and if nine hundred and ninety-nine in a thousand go wrong, she simply scraps them and goes cheerfully on with her everlasting business. An amusing person! One can imagine some Principality or High Intelligence, a visitor from Aldebaran, let us say, looking on at these queer doings on her part and remarking: “My dear, what a silly fool you are to waste so much energy in trying to do an impossible thing.”

And--nettled at his air of superiority--her sharp reply:

“Oh yes, now you say that, I’m reminded of a visitor I once had from--oh, I don’t know exactly where--somewhere in the Milky Way--just when I was experimenting with my snake idea. To make a vertebrate without any organs of progression, yet capable of getting freely about--ha, ha, ha, how very funny! I’d like him to come back now to show him a tree-snake with a cylindrical body two yards long and no thicker than a man’s middle finger, green as a green leaf and smooth as ivory, going as freely about in a tree as a cat or a monkey. Also my blue sea-snake, cleaving the water like a fish; also my ground-serpents of numberless types, moving swiftly over the earth with a grace surpassing that of creatures endowed with organs of progression.”

But not a word did she say about the flying-fish, which was not a great success.

Then he: “Well, I should advise the person from the Milky Way to keep out of _your_ way. No doubt you have done clever things, but the snake problem was not so very difficult after all. You thought of the rib and the scale, and the thing was done.”

And she: “Yes, it was quite simple, and so when I wanted to make reptiles fly I thought of this and of that and of something else and the thing was done.”

Then he: “Yes, yes, my dear lady--that was clever, too, no doubt; only your flying lizard wasn’t wound up to go on for ever--not as a lizard at all events; and what I should like you to tell me is: When you have got your little beast in the air how are you going to get him to stay there?”

Her sharp reply was: “By thinking,” for she was angry at his supercilious Aldebaran airs. And, put on her mettle, it was only by sheer hard thinking that she finally succeeded in accomplishing her object--this, too, as it were, by means of a subtle trick. For the bird problem had been a very different one; her experiments with flying lizards had suggested it, and she was able to create this new and finer being an inhabitant of the air by giving it its peculiar pointed wedge shape, its covering of feathers, with feathers for flight--hard as steel, light as gossamer, bloodless, nerveless. And correlated with shape and flight and life in the air, a development of power of vision which, compared with that of mammals and reptiles, is like a supernatural faculty.

Her subtle trick, in the case of the bat, was to reverse the process followed in building up the bird; to suspend her beast head down by the toes instead of making him perch with his head up to keep it cool; to neglect the vision altogether as of little or no account; and, on the other hand, instead of the light, hard, nerveless feather wings, to make the flying apparatus the most sensitive thing in Nature, barring the antennae of insects; a bed and field of nerves, so closely placed as to give the membrane the appearance of the finest, softest shot silk. The brains of the creature, as it were, are carried spread out on its wings, and so exquisitely delicate is the sensitiveness of these parts that in comparison our finger-tips are no more quick of feeling than the thick tough hide of some lumbering pachyderm.

I have handled scores of bats in my time, and have never had one in my hand without being struck by its shrinking, shivering motions, the tremors that passed over it like wave following wave, and it has seemed to me that the touch of a soft finger-tip on its wing was to the bat like a blow of a cheese- or bread-grater on his naked body to a man.

Now any one, even the intelligent foreigner from Aldebaran, would have imagined that such a creature so constructed would not have maintained its existence in this rough world: a sudden storm of rain or hail encountered in mid-air would have destroyed it, and in its pursuit of insects in leafy places it would have been exposed every minute to disabling accidents. But it did not happen so. That exquisite super-sensitiveness, that extra sense, or extra senses, since we do not know how many there are, not only kept it in the air, able to continue the struggle of life in the particular forest, the district, the region, the continent where it came into being, but sent it abroad, an invader and colonist, to other lands, other continents all over the globe, including those far-off isolated islands which had been cut off from all connexion with the rest of the earth before mammalian life was evolved, and had no higher life than birds, until this small beast came flying over the illimitable ocean on his wings, to be followed a million years later by his noble relation in a canoe.

We see then that the bat is a very wonderful creature, one of Nature’s triumphs and masterpieces, and on this account he has received a good share of attention from the zoologists. Nevertheless, after looking through a large amount of literature on the subject, the old idea persists that we know little about the bat--little, that is to say, compared with all there is to be known. How very little my own researches can add to its life history these meagre observations and comments will serve to show.

Walking by the Test, near Longparish, one evening, I noticed a number of noctules, our great bat, gathered at a spot where some high trees, elms and beeches, grew on the edge of a wet meadow. The bats were flying up and down in front of the trees, feasting on the moths and other insects that abounded there. I wondered how it came about that these big bats had this rich table all to themselves, seeing that the small common bat is by far the most numerous species in that locality. After I had stood there watching them for a few minutes a common bat appeared, and at once began flying to and fro among them; but very soon he was spotted and attacked by a big bat, and then began the maddest chase it was possible to see, the little one doubling wildly this way and that, now mounting high in the air, then plunging downward to the grass, anon losing himself in the trees, to reappear in a few moments with his vicious persecutor sticking so close that the two often seemed like one bat. Finally, they went away out of sight in the distance, and keeping my eyes in the direction they had gone, I saw the big one return alone in about seven or eight minutes and resume his flying up and down with the others. It struck me that if I could have followed or kept them in sight to the finish I should probably have witnessed a little tragedy: the terror of the one and the fury of the other suggested such an end. The keen teeth once fixed in his victim’s neck, the noctule would wash his supper of moths and beetles down with a draught of warm blood, then drop the dead body to the earth before returning to his companions. This is conjecture; but we know that bats have carnivorous propensities, and that in some exotic kinds the big will kill the little, even their own young. Probably they all have something of the vampire in them. The female bat is a most devoted parent, carrying her young about when flying, wrapping them round with her silken wings as with a shawl when in repose, suckling them at her breast even as the highest of the mammalians do. One would not be surprised to learn that the deadliest enemy of her little ones, the one she fears most, is her own consort.

Whether bats migrate or not has long been a moot question, and Millais, our latest authority, and certainly one of the best, has answered it in the affirmative. But the migration he describes is nothing but a change of locality--a retirement from their summer haunts to some spot suitable for hibernation, in some instances but a few miles distant. Other hibernating creatures--serpents, for example--have the same habit, and though compelled to travel on their bellies, they do nevertheless return year after year to the old laying-up places. The question of a seasonal movement in bats, similar to migration in birds, greatly exercised my young mind in former years in a country where bats had no business to be. This was the level, grassy, practically treeless immensity of the pampas, where there were no hollow trunks, nor caves and holes for bats to shelter in, nor ruins and buildings of brick and stone which would be a substitute for natural caverns. Human dwellings were mostly mud and straw hovels, and the only trees were those planted by man, and were not large and could not grow old. The violent winds swept this floor of the world, which was unsheltered like the sea. Yet punctually in spring the bats appeared along with the later bird migrants, and were common until April, when they vanished, and then for six months no bat would be seen in or out of doors. Clearly, then, they were strictly migratory, able like birds to travel hundreds of miles and to distribute themselves over a vast area. They were, in fact, both migrants and hibernators, since we cannot but suppose that they forsook the pampas only to find some distant place where they could pass their inactive period in safety.

At one point, about two hundred miles south of Buenos Ayres city, the level pampa is broken by a range of stony hills, or sierras, standing above the flat earth like precipitous cliffs that face the sea. On my first visit to that spot I travelled with a party of eight or nine gauchos, and evening coming on near our destination, we camped about a league from the foot of the hills and built a big fire. Just as we had got a good blaze a loud cry of “Morcielagos!” (bats) from one of the men made us look up, and there, overhead, appeared a multitude of bats, attracted by the glare, rushing about in the maddest manner, like a cloud of demented swifts. In a few moments they vanished, and we saw no more of them. Bats, I found, were extremely abundant among these hills, and here they were probably non-migratory.

But the main question about bats is always that of their sense-organs, in which they differ not only from all other mammalians but from all vertebrates, and if in this there is any resemblance or analogue to any other form of life it is to the insect. As to insect senses we are very much in the dark. The number of them may be seven or seventeen, since insects appear to be affected by vibrations which do not touch us. We exist, it has been said, in a bath of vibrations; so do all living things; but in our case the parts by which they enter are few; so too with all other vertebrates except the bat alone, and a puzzle and mystery he remains. What, for example, are the functions of the transverse bands on the wings formed of minute glands; the enormous expanse of ears in the long-eared bat; the earlet, a curious development of the tragus; and the singular leaf-like developments on the nose of the horseshoe bat? We suppose that they are sense-organs, but all we know, or half know, about the matter is ancient history; it dates back to the eighteenth century, when Spallanzani, finding that bats were independent of sight when blinded and set flying in winding tunnels and other confined places, conjectured that they were endowed with a sixth sense. Cuvier’s explanation of these experiments was that the propinquity of solid bodies is perceived by the way in which the air, moved by the pulsations, reacts on the surface of the wings. Thus the sixth sense was a refinement, or extension, of the sense of touch--an excessive sensitiveness in the membrane. Blind men, we know, sometimes have a similar extreme sensibility of the skin of the face. I have known one who was accustomed to spend some hours walking every day in Kensington Gardens, taking short cuts in any direction among the trees and never touching one, and no person seeing him moving so freely about would have imagined that he was totally blind.

My own experiments on bats in South America were inconclusive. I used to collect a dozen or twenty at a time, finding them sleeping by day on the trees in shady places, and after sealing up their eyes with adhesive gum, liberate them in a large room furnished with hanging ropes and objects of various sizes suspended from the rafters. The bats flew about without touching the walls, and deftly avoiding the numerous obstacles; but I soon discovered that they were able when flying to use the hooked claw on the wing to scratch the gum away and pull the eyelids open, and whenever one came to grief I found that its lids had not been opened.

One can see at once that an experiment of this kind is useless. The irritation of the gum and the efforts being made to remove it by the animal while flying cloud the extra sense or senses, and it loses its efficiency.

What the bat can do I discovered by chance one summer afternoon in an English lane. It was one of those deep Hampshire lanes one finds between Selborne and Prior’s Dean, where I was walking just before sunset, when two common bats appeared flying up and down the lane in quest of flies, and always on coming to me they circled round and then made a vicious little stoop at my head as if threatening to strike. My brown and grey striped or mottled tweed caps and hats have often got me into trouble with birds, as I have told in a chapter in _Birds and Man_, and it was probably the colour of my cap on this occasion that excited the animosity of this pair of bats. Again and again I waved my stick over my head on seeing one approach, but it had not the slightest effect--the bat would duck past it and pass over my cap, just grazing it boldly as ever. Then I thought of a way to frighten them. My cane was a slim pliable one, which gave me no support, and was used merely to have something in my hand--a thin little cane such as soldiers carry in their hands off duty. Holding it above my head, I caused it to spin round so rapidly that it was no longer a cane in appearance, but a funnel-shaped mist moving with and above me as I walked. “Now, you little rascal,” said I, chuckling to myself as the bat came; then making the usual quick circle he dashed down through the side of the misty obstruction, made his demonstration over my cap, and passed out on the other side. I could hardly credit the evidence of my own eyes, and thought he had escaped a blow by pure luck, and that if he attempted it a second time he would certainly be killed. I didn’t want to kill him, but the thing was really too remarkable to be left in doubt, and so I resumed the whirling of the stick over my head, and in another moment the second bat came along, and, like the first, dashed down at my cap, passing in and out of the vortex with perfect ease and safety! Again and again they doubled back and repeated the action without touching the stick, and after witnessing it a dozen or fifteen times I could still hardly believe that their escape from injury was anything but pure chance.

Here I recall the most wonderful flying feat I have witnessed in birds--a very common one. Frequently when standing still among the trees of a plantation or wood where humming-birds abounded, I have had one dart at me, invisible owing to the extreme swiftness of its flight, to become visible--to materialise, as it were--only when it suddenly arrested its flight within a few inches of my face, to remain there suspended motionless like a hover-fly on misty wings that produced a loud humming sound; and when thus suspended, it has turned its body to the right, then to the left, then completely round as if to exhibit its beauty--its brilliant scale-like feathers changing their colours in the sunlight as it turned. Then, in a few seconds, its curiosity gratified, it has darted away, barely visible as a faint dark line in the air, and vanished perhaps into the intricate branches of some tree, a black acacia perhaps, bristling with long needle-sharp thorns.

The humming-bird is able to perform this feat a hundred times every day with impunity by means of its brilliant vision and the exquisitely perfect judgement of the brilliant little brain behind the sight. But I take it that if the bird had attempted the feat of the bat it would have killed itself.

It is a rule in wild life that nothing is attempted which is not perfectly safe, though to us the action may appear dangerous in the extreme, or even impossible. At all events, I can say that these bats in a Selborne lane taught me more than all the books--they made me see and understand the perfection of that extra sense.

But it is just that same sense which Spallanzani and Cuvier wrote about, and we cannot but think that the bat has something more than this. That peculiar disposition of glands and nerves on the wings, the enormous size of the ear in the great-eared bat, the ear-leaf, and leaf-nose, and the other developments and excrescences on the face which give to some species a more grotesque countenance than was ever imagined by any medieval artist in stone--these are doubtless all sense-organs, and the question is, are these all additions to the one sense we know of--an extension and refinement of the sense of touch? I think they are more than that, and there are a few facts that incline one to believe that knowledge comes to the bat through more ports than one--knowledge of things far as well as near. One observation made by Millais points to this conclusion. He noticed that a crowd of noctule bats that sheltered in a hollow tree by day, on issuing in the evening all took flight in the same direction, and that the line of flight was not the same, but varied from day to day; that on following them up to the feeding area he discovered that insects were always most abundant at that spot on that evening. It came to this--that on issuing from the hollow tree every bat in the crowd, issuing one or two at a time and flying straight away, knew where to go, south, east, west, or north, to some spot a mile or two away. The bat too, then, like the far-seeing vulture, is “sagacious of his quarry from afar,” but what Nature has given him in place of his dim, degenerate eyes to make him sagacious in this way remains to be found out.