Chapter 35

CHAPTER III.SUB-ORDER II.—MICROCHIROPTERA, OR INSECTIVOROUS BATS.HORSESHOE BATS AND MEGADERMS.

INSECTIVOROUSBATS—Mr. Dobson’s Objection to the Name—Characteristics—Nasal Appendages—THEVESPERTILIONINE ANDEMBALLONURINEALLIANCES—The Fur in the two Alliances—THEHORSESHOEBATS—General Characteristics—Distribution—Diet—Carnivorous Propensities—GREATERHORSESHOEBAT—General Appearance—“Nose Leaves”—Habitat—THELESSERHORSESHOEBAT—Habitat—THEMOURNINGHORSESHOEBAT—THEAUSTRALIANHORSESHOEBAT—THEORANGEBAT—PHYLLORHINÆ—THEDIADEMBAT—Character of their “Nose Leaves”—Captain Hutton’s Account of their Habits—THEPERSIANTRIDENTBAT—THEMEGADERMS—THELYREBAT—Characteristics—Called Vampire by Europeans in India—Mr. Blyth’s Account of a Megaderm’s Blood-thirstiness—THECORDATELEAFBAT—THEAFRICANMEGADERM—THEDESERTBAT

THEsecond sub-order of Bats—which includes a much larger number of species, displaying a far greater variety of characters than those which have hitherto occupied our attention—has received the name ofInsectivora, from the general nature of the diet of the animals composing it. Mr. Dobson objects to this name, chiefly on account of there being already anorderof Mammalia bearing the same designation; and he proposes to call these BatsMicrochiroptera, in allusion to the small size of most of the species in comparison with the majority of the Pteropidæ. Moreover, although the food of most of these Bats consists exclusively of insects, some of them feed, at least partially, upon other vertebrate animals, and a few are known to eat fruit.

The Bats belonging to this second sub-order may be at once distinguished by the structure of their molar teeth, which are armed with acute tubercles, separated, more or less completely, by transverse furrows. The ears also differ from those of the Pteropidæ, in that the two margins of the conch start from different points on the surface of the head, and, in a great number of cases, they are complicated by a membranous lobe, springing from near their base, or by a great development of the tragus, or anterior lobe of the ear. The tail in these Bats is generally well developed, and the index finger is never terminated by a claw.

A considerable number of Insectivorous Bats of different families have their noses furnished (wecannot say adorned) with curious leaf-like appendages, often of most complicated construction (see some of the illustrations), and these organs, as has already been stated, probably assist materially in the exercise of that delicate sense of touch which supplements or takes the place of the power of vision in guiding the Bats in their obscure abodes. In general, the presence or absence of nasal appendages being an exceedingly obvious character, has been adopted by zoologists as the means of classifying these Bats, and the order has been commonly divided into two groups—the Istiophora, or those with a nose-leaf, and the Gymnorhina, or Anistiophora, in which there is no such appendage. Mr. Dobson, who has devoted a great deal of attention to the Chiroptera, finds, however, that by following this system certain forms are grouped together which have little in common, whilst in other cases real affinities are lost sight of, and he suggests another mode of division, which, for many reasons, appears to be the most natural that has hitherto been proposed. He ranges the families of his Microchiroptera in two alliances, the leading characters of which may be briefly indicated as follows:—

HAIRS OF BATS,MAGNIFIED.(FromDobson’s “Monographof Asiatic Bats.”)

In the first, orVespertilionine alliance, so called from its including our common Bats (Vespertiliones), the tail is generally long, never absent, and always entirely enclosed in the interfemoral membrane, with the exception of the extreme tip, which projects a very little; the pre-maxillary bones are rudimentary, and the upper incisor teeth which they carry small and weak; and the first phalanx of the middle finger is extended in repose in a line with the metacarpal bone.

In the second, orEmballonurine alliance, so called from one of the genera included in it, the tail, which is frequently absent or short, except in two or three species, is not contained within the interfemoral membrane, but has its extremity free, usually perforating the membrane and appearing on its upper surface. The pre-maxillary bones are generally well developed, and the incisors large; and the first phalanx of the middle finger is folded forward in repose above or below the metacarpal bone.

The character derived from the condition of the middle finger in repose seems to be regarded as of the most importance by Mr. Dobson, who says that it is connected with differences in the habits of the animals; but those of the tail and incisor teeth will be most useful to the student in determining to which alliance he is to refer his specimens; and, although they are liable to exceptions in the second group, will neverbothfail in the same individual.

A striking confirmation of the naturalness of this arrangement is to be found in the fact that even the microscopic character of the fur differs in the two alliances. In the first, the longer hairs of the fur when magnified show a series of scales, imbricated or partly overlapping each other, something like the grains of corn in the ear, the tips, which are not acute or very prominent, forming a sort of spiral line round the surface of the hair (seeFig.a). In the second alliance, on the contrary, the scales—which are smaller and narrowed, with acute and projecting tips—are arranged in rings round the hair, giving it a somewhat jointed appearance (seeFig.b). Mr. Dobson has examined the fur of a majority of the genera of these Bats, and also submitted his specimens to the examination of Dr. J. D. Macdonald, F.R.S., and both these gentlemen find the differences in the structure of the hair always perfectly in accordance with the arrangement above indicated, with but two exceptions, one of them being a genus which really forms a sort of connecting link between the two alliances, and the other having fur quite different from that of any other Bat, and in which the scales can hardly be distinguished.

VESPERTILIONINE ALLIANCE.

The Bats of this family are usually called Horseshoe Bats, from the circumstance that their noses are furnished with leaf-like membranous appendages of rather complicated structure, the front part of which is usually something like a horseshoe in its form (seefigure on next page). The nostrils are situated within this horseshoe, between it and the other parts of the nose-leaf, which vary considerably in their shape and structure. The middle finger has two phalanges, or joints, beyond the long metacarpal bone,a character common to all the Bats of this alliance, with only a single exception; andthe ears have no tragus. Throughout the family there are two small incisor teeth in the upper jaw, and four in the lower, and three true molars on each side in both jaws; but the number of pre-molars varies, being usually two on each side in the upper jaw, and either two or three in the lower; whilst in one curious species the upper pre-molars are only one on each side.

HEAD OF THE GREATER HORSESHOE BAT.

TheRhinolophidæare confined to the Eastern hemisphere, of which they chiefly inhabit the warmer parts. They are generally insectivorous in their habits, but some of the larger species are said to prey upon other vertebrate animals, and not even to spare their smaller brethren. Thus, Mr. Frith informed Mr. Blyth that “a number of these Bats were in the habit of resorting to the verandah of his residence in Mymensing (Burmah), and that every morning the ground under them was strewed with the hind-quarters of Frogs and the wings of large Grasshoppers and Crickets. On one occasion the remains of a small fish were observed; but Frogs appeared to constitute their chief diet—never Toads, and of a quiet evening these animals could be distinctly heard crushing the heads and smaller bones of their victims.”

Captain Hutton also states that various species ofRhinolophidæ, and someVespertilionidæ,[164]when confined with some smaller species than themselves, will prey upon them; and he suggests that these carnivorous propensities may be “the reason why the larger species keep aloof in pairs, instead of congregating, as do some of the smaller kinds.” In illustration of this suggestion he gives the following interesting account of a cave frequented by Bats:—He says, “I know of an enormous cave at Mussooree, to which various species, both large and small, are in the habit of resorting for rest and concealment during the day. Standing within this spacious vault in the earliest hours, just before the first streaks of day appear, the spectator is perfectly astonished at the numbers of Bats resorting to it; not, however, in one promiscuous crowd, but in separate detachments, each seeking its own particular quarter of the cavern, and alighting against the sides, at first within reach of a Butterfly-net, and commence crawling upwards and backwards to spots beyond the reach of invasion from below. Here, in one spot, will be seen a pair ofRhinolophus luctus, hanging high up, and quite apart from all the rest; in another place hangs a pair ofPhyllorhina armiger, the large ears and the facial crests in active tremulous motion as the head is turned in every direction to ascertain that no intruder is nigh its dwelling-place, until, this restlessness gradually passing off, the animal hangs at length quietly suspended by the feet. In another direction are a dozen or more ofRhinolophus minor, rapidly scrambling all together, like a lot of crabs, up the inequalities of the rocky surface, and hurriedly disappearing into some deep, narrow crack or crevice; while again, in another part, the same scene is observed, as dozens of a very small species ofNycticejus(Scotophilus) scramble into similar hiding-places, to rest in peace until the hour for again emerging in search of prey calls them all forth once more.”

Although, as already stated, most of the Horseshoe Bats inhabit warm countries, several species are found in more temperate regions. One of these is the Greater Horseshoe Bat (Rhinolophus ferrum-equinum), which occurs, although not very abundantly, in various parts of the South of England. He is a puffy and rather pursy-looking little fellow, with a head which appears full large for his body. The length of his head and body is about two and a half inches, and that of his tail, which is entirely enclosed in the interfemoral membrane, about an inch and one-third. His wings have an expanse of thirteen or fourteen inches. The fur on the upper surface is reddish-grey, and on the lower surface very pale grey; the membranes are of a dingy brown colour, and the ears and nasal appendages pale brown. The ears are large, broad at their attachment to the head, pointed and turned outwards at the apex. From the outer margin ten or a dozen transverse furrows run towards the middle of the ear. The outer margin, at its junction with the head, is also continuous with a low rounded lobe[166]which bounds the aperture of the ear in front, and may be used to close the cavity. The nasal appendages, or “nose-leaves,” are very curious and complicated (seefigure, p. 281). The anterior, or horseshoe-shaped portion, lies longitudinally upon the nose, and is formed of three concentric elevations, the innermost of which bounds the depression in which the nostrils are placed. Between the nostrils arises the central process, the anterior portion of which forms a sort of cup, behind which the process is slightly narrowed and excavated, but again widens before terminating in a short but rather sharp point. This point overhangs the third, or frontal leaf, which touches the horseshoe portion, and is about as broad as the latter at their junction, and tapers up to a point upon the forehead. The eyes, which are like little black beads, are placed on each side of the junction of the horseshoe and the frontal leaf.

GREATER HORSESHOE BAT.

These curious structures are found with slight variations in all the species of the genusRhinolophus, to which this Bat belongs. The nasal appendages vary somewhat in the form and proportions of their parts, and the basal lobe, or antitragus of the ears, is developed in different degrees in various species, but their general character is always recognisable. Other marks by which the species of this genus may be recognised are the presence of three joints in the first toe, the others possessing only two, and the dentition, which includes the full number of teeth developed in the family, namely, incisors,24, canines,1–11–1, pre-molars,2–23–3, molars,3–33–3.

The Greater Horseshoe Bat lives chiefly in deserted quarries, old buildings, and natural caverns,and is said to frequent the darkest and most inaccessible parts of such excavations. Thus, Montagu found it in company with the smaller species next to be described, in “Kent’s Hole,” near Torquay, “a retreat,” says Mr. Bell, “so dark and gloomy, that no other species, even of this lucifugal family, were found to frequent it.” In such retreats it passes the winter in a torpid state, coming forth in the spring to prey upon the insects which constitute its sole nourishment. It is said often to feed upon chafers, but to eat only the body. That it does not disdain smaller game, however, appears from Pennant’s record of its original discovery in England by Dr. Latham, who obtained it at Dartford, in Kent, where, says Pennant, “they are found in greatest numbers in the saltpetre houses belonging to the powder-mills; and frequent them during the evening for the sake of the Gnats which swarm there. They have also been found during winter, in a torpid state, clinging to the roof.” Mr. James Salter, in a communication to Mr. Bell, mentions his having caught one of these Bats on the 29th of September, 1865, in so appropriate a locality as the “haunted room” at Tomson Manor House, Dorsetshire. It was flitting about the room when he went to bed, having entered by an open window. “On the next three nights, which were still and calm,” he says, “I saw numbers of (apparently) the same Bats flying around the house among a grove of sycamores. The flight was low, short, and sluggish, both in the room and out of doors.”

This Bat suckles its young, after the usual fashion of Bats, at the two pectoral teats. Several authors, and among others Geoffroy, have maintained that the Horseshoe Bat, and indeed all the species of the family to which it belongs, possess, besides the ordinary pectoral teats, a second pair situated on the groin. This, however, is not the case, for the nipple-like appendages situated on the groin in the females of this group have been proved to have no connection with any mammary glands.

In England the Greater Horseshoe Bat has been found in various localities in the southern counties. Besides Dartford, where it was originally discovered in this country, Mr. Bell mentions Margate, Rochester, and Bristol Cathedrals, Colchester, caverns at Clifton, and the Undercliff of the Isle of Wight. On the continent of Europe it inhabits the whole of the southern and central parts from Spain and Portugal in the west, to Greece and Turkey in the east, extending northwards as far as central Germany and southern Russia. In Asia it is found in Syria and Asia Minor, and ranges thence eastwards to Nepaul and Mussooree; whilst in Africa it appears to stretch from Algeria to the Cape of Good Hope. Over this wide range, as might be expected, the species does not always display precisely the same characters, and variations of greater or less importance have led to the establishment of supposed distinct species; amongst others, the JapaneseRhinolophus nipponis regarded by Mr. Dobson as identical with our Greater Horseshoe Bat.

The Lesser Horseshoe Bat, the second British species of this genus, was formerly regarded only as a small variety of the preceding, and was first distinguished by Colonel Montagu, who also first detected its occurrence in England. It is about half an inch shorter than the Greater Horseshoe Bat, and its expanse of wing is about nine inches. In general aspect it resembles the larger species. The fur is equally soft and full, and of the same colours, except that the upper surface is a little browner, and the lower parts rather more tinged with yellow. In the ears the transverse furrows are scarcely perceptible, and the basal lobe is rather larger in proportion. There are also some small, but constant, peculiarities in the structure of the nasal appendages. The central leaf is less prominent and less cupped at the base than inR. ferrum-equinum; the frontal leaf is lance-shaped, and not much dilated at the sides towards the base; and the outer margin of the horseshoe is slightly crenulated (seefigure).

HEAD OF LESSERHORSESHOE BAT.

In its habits this kind seems to agree with the Greater Horseshoe Bat. As already mentioned, the two species were taken together by Montagu in “Kent’s Hole,” clinging in considerable numbers to the vaulted roof of the interior apartments. It was first discovered by him in rather a singular situation, namely, a hole over a baker’s oven, which it had entered through a fissure. He afterwards found it in a dark shed surrounded by tall trees, at Lackham, in Wiltshire. In the second edition of Mr. Bell’s “British Quadrupeds” there is an interesting account of the manners of this species. The writer mentions the occurrence of the Lesser Horseshoe Bat in two localities in Warwickshire, one of these being the roof of the neglected mansion of the Marquis of Hertford at Ragley, near Alcester. Numbers of Long-eared Bats were found, chiefly in pairs, in holes in the massive timbers, but “although several of the Horseshoe Bats were seen flitting in the deep gloom, broken only by an occasional gleam of light through some small crevice, and by our lighted candle, yet a careful search was for some time unrewarded by the discovery of a single individual in its resting-place. A great accumulation of excrement around a huge central stack of chimneys at length attracted attention, and a long stick, thrust upwards in a narrow opening between the chimneys, soon dislodged several of these Bats, which were caught as they descended, and before they were well on the wing, after which pursuit proved useless. Some of these examples being at various times liberated in a room, exhibited extraordinary powers of flight. One of them displayed in its search for a means of exit an ability which was quite extraordinary. It literally flew into every part of the room, and behind and under everything, even under a bookcase standing against a wall, although there was scarcely a space of three inches between it and the floor ... it flew into a vacancy occasioned by the removal of a moderate octavo volume, without having so much as touched anything with the tips of its wings.” In examining the window this Bat searched every pane inch by inch, its wings while thus occupied being “kept in a vibratory state, the face of the animal being directly in front of the glass, and very near to it, as if looking out of window.” The impression produced on the observers was that the animal was “feeling its way about like a blind person;” but “at the same time its shyness when approached sufficiently testified that its organs of sight were by no means inactive.” In order to rest, instead of adhering like most other Bats against some object by means of its claws, it always sought for something from which it could hang freely. According to Dr. Leach this Bat is easily tamed, but is fond of concealing itself.

Besides the English localities already mentioned, the Lesser Horseshoe Bat is found not unfrequently at Cirencester and in some parts of Ireland. Professor King obtained it in Galway; and from the statements of Mr. Foot and Professor Kinahan it appears to be the commonest Bat in some parts of County Clare. Its European distribution is much the same as that of the preceding species, but it seems to extend rather farther to the north. It is also found in the Caucasus and in South-western Siberia. North African specimens are said to be paler in colour than European.[168]

HEAD OF THE MOURNINGHORSESHOE BAT.

Other species ofRhinolophusare met with chiefly in India and the Asiatic Islands. One of the most striking of them, and indeed the largest species of the genus, measuring more than three and a half-inches in length, is the Mourning Horseshoe Bat (Rhinolophus luctus, seefigure), an inhabitant of the higher grounds of India, Ceylon, Java, Sumatra, and the Philippine Islands. This Bat is remarkable for the great development of the nasal appendages, the central leaf being expanded on each side into a lobe nearly as long as the central ascending portion, the horseshoe very large, so as to project beyond the upper lip, and the frontal leaf so long as to ascend between the ears. The latter organs are also ofgreat size, and have a large basal lobe (antitragus) separated from the outer margin of the ear by a deep angular notch. The fur is very long and thick, and usually black with grey tips, so that the species appears to be in mourning, whence its specific name; it is, however, subject to considerable variation in this respect, some specimens being reddish-brown. Captain Hutton, who resided for a considerable time at Mussooree, has described the habits of this Bat, which he found in the Himalayas up to an elevation of 5,500 feet, where it was “hanging from the roof of an outhouse, looking, with its ample black wings folded round it as a cloak, somewhat like a large black cocoon.” He says that it commences its flight rather early in the evening, and generally keeps at about twenty or thirty feet from the ground, wheeling, with a somewhat heavy and noiseless flight, around buildings and large trees in search of small Moths and other insects. He adds that he has taken them from the roofs of outhouses and from wide caves in limestone rocks, and that they seem generally to live in pairs and not in communities, although several pairs may be found in a large cave. At Mussooree they fly only during the warmer months, and remain in a semi-torpid state during the winter, but Captain Hutton suggests that in the warmer climates of Sikkim and the Khasia hills they may be active all the year round. Another smaller species with a similar central nose-leaf has been described under the name ofR. trifoliatus; it is an inhabitant of the eastern coast of India, Java, and Borneo. These two species form the genusAquiasof the late Dr. Gray.[170]

A single species ofRhinolophusoccurs in Australia, having been obtained from caverns on the Murrumbidgee River, and also near Richmond River in New South Wales. It has pale mouse-coloured fur. The ears are large, with long basal lobes, and the nasal appendages are larger than in the European species, the frontal leaf being lance-shaped and long, and the horseshoe rather deeplynotched in front. In allusion to the large size of the nose-leaves this species has been calledR. megaphyllus.

ORANGE BAT.

Another Australian species of Leaf-nosed Bat, belonging, however, to a distinct genus, of which, indeed, it is the sole representative, is the Orange Bat (Rhinonycteris aurantia, seep. 285). This species, which is about two inches long, is clothed with a soft fur, which, in the male, is of a bright orange colour, and in the female pale yellow. This coloration is exceedingly remarkable in an animal of nocturnal habits, as these are generally rather sombre in their tints. The nose-leaf in the Orange Bat is somewhat similar in its character to that of the trueRhinolophi, but in its other peculiarities this Bat is rather related to those which we shall next have to describe, and thus forms a sort of transition between the two groups. It has the toes equal, and composed of only two phalanges, a character which distinguishes it from the preceding species; whilst its resemblance to them in the structure of the nose-leaf serves to separate it from its following allies. The teeth resemble those ofRhinolophus. In repose the tail and interfemoral membrane are generally turned back, which appears to be the case in some at all events of the following species. This species inhabits Northern Australia, and is especially abundant on the Coburg peninsula. It reposes during the day in hollow spouts and holes of the gum-trees.

HEAD OF THE MALE AND FEMALE DIADEM BAT, ENLARGED.(After Dobson.)

Whilst theRhinolophiare chiefly inhabitants of elevated localities, especially in tropical regions, the members of the second large genus of Horseshoe Bats (Phyllorhina) for the most part frequent the plains and lower hills of the same countries. The most definite character separating thePhyllorhinæfrom theRhinolophiis the presence of only two phalanges (joints) in all the toes of the hind feet, the first toe inRhinolophushaving three such joints. The nose-leaf consists of a horseshoe and of two other portions, which, however, differ considerably in form from those ofRhinolophus; the anterior portion being horseshoe-shaped, but not notched in front, the intermediate part not forming a prominent process, but broad and heart-shaped, and the posterior part broad, erect, and concave in front. The number of teeth is the same as inRhinolophus, except in one species (P. tridens), which has only a single pre-molar on each side in the upper jaw. Fourteen species of this genus are cited by Mr. Dobson as inhabiting the East Indies and the islands of the Eastern Archipelago, and one of them, the Diadem Bat (Phyllorhina armigera), which is found among the mountains of Northern India, extends its range as far north as Amoy in China. The characters of the nose-leaf in this species will be seen from theannexed figures, which show strikingly the great complexity of this curious apparatus. Behind the nose-leaf is the aperture of a peculiar sac situated in the forehead, which is characteristic of many species of the genus, and which can be turned out like the finger of a glove at the pleasure of the animal, and the surface of which secretes a waxy substance. Its centre bears a tuft of straight hairs, the tips of which project from the orifice when the sac is drawn in. The Diadem Bat is rather a large species, the head and body measuring from three and a half to four inches in length, and the expanse of the wings being about two feet. Its general colour is light brown, darker on the upper surface, where the hairs are ringed with three colours—pale sepia at the base, then grey, then dark sepia, with the extreme tips a little paler.

The late Captain Hutton has given an account of the habits of this species as observed by him at Mussooree, where specimens were captured at elevations of 5,500 and 6,000 feet above the sea-level. At the latter elevation a pair resided in a loft, from which they issued every evening about dusk, and flew with a slow, deliberate flight round the house, from which they never departed to any great distance. They did not remain on the wing long at a time, but retired at intervals to their dwelling-place in the loft. The same writer describes these Bats, which seem to emerge from their concealment very early in the evening, as leisurely wheeling with noiseless flight round some wide-spreading oak, attracted by the loud discordant note of a largeCicada, which is abundant during the rainy season, and only pours forth its clamorous evening song just as the sun begins to dip below the horizon. “It is during this dreadfully harsh concert,” he adds, “when almost every tree sends forth its stunning notes, that this Bat emerges from its hiding-place, wheeling round and round the trees, scanning each branch as he slowly passes by, now rising to a higher circle, and then descending towards the lower branches, until at length, detecting the unfortunate minstrel, it darts suddenly into the tree, and snatching the still screaming insect from its perch, bears it away.”

In captivity, according to Captain Hutton, the large ears of this animal are kept in a constant, rapid, tremulous motion, and the creature emits a low purring sound, which is exchanged for a sharp squeak when it is alarmed or irritated. When it is suspended in a resting attitude the tail and interfemoral membrane are turned up, not in front, as usual in Bats, but behind, upon the lower part of the back. In this species and its allies Captain Hutton further noticed that when they are disturbed “the whole of the facial crests are kept in a state of constant agitation; and as the animal hangs suspended by the feet, the head and muzzle are stretched forth, and turned about in every direction, as if for the purpose of sniffing out the presence of danger, and ascertaining the cause of the disturbance.”[174]

Under this name Mr. Dobson describes a very remarkable species of this family in which the nasal appendages seem to attain the extreme of complexity (seefigure). The ears also are of very peculiar construction. This is a small species, about two and a quarter inches long, and of a pale buff colour, specimens of which were obtained at Shiraz in Persia at an elevation of about 4,750 feet above the sea. Its nearest ally, curiously enough, is to be found, according to Mr. Dobson, in the Australian Orange Bat (Rhinonycteris aurantia).

HEAD OF THE PERSIAN TRIDENT BAT,ENLARGED. (After Dobson.)

Frith’s Short-tailed Bat (Cœlops Frithii) is a still more remarkable species, single specimens of which have been obtained from the Sunderbunds and from Java. It is most nearly allied to thePhyllorhinæ, but has the horseshoe part of the nose-leaf composed of two notched pieces, the front lobes of which cover the base of two long hanging leaflets, the tail short, the interfemoral membrane deeply excavated, and the index finger unusually long, and composed chiefly of the metacarpal bone.

The development of peculiar nasal appendages for which theRhinolophidæare remarkable is still more striking in some species of another family, the members of which were formerly included in the preceding. In these Bats (theNycteridæof Mr. Dobson) the ears are enormously developed, membranous, and united either by a portion of their inner margins, or by a transverse band of membrane, the tragus or earlet is greatly developed, and the middle finger contains two phalanges.[176]

The species inhabit the warmer parts of the Old World.

HEAD OF THE LYRE BAT.

The extraordinary development of the ears and of the membranous appendages of the nose is greatest in the species of this genus, which has in consequence been denominatedMegaderma, two of which inhabit tropical Asia, whilst two occur only in the warmer parts of Africa.

Of all the species the most abundant and best known is the Lyre Bat (Megaderma lyra, seefigure), which is found with but little variation in its characters throughout continental India, from Cashmere to Cape Comorin, and also in the adjacent island of Ceylon. This extraordinary little creature, which measures only about three and a half inches in length, and is of a slaty blue colour, paler beneath, has its ears considerably longer than its head, and united for nearly half the length of their inner margins, and the earlets (tragi) very long, divided at the end into two parts, one of which, the posterior, is pointed, and a good deal longer than the other, which is rounded off at the end. The ears are, in fact, about half the length of the head and body. The nose-leaf starts from a nearly circular base, lying horizontally upon the muzzle, and rises like a sort of strap more than half an inch long, the front surface of which has a projecting ridge running up its middle, and corresponding to a deep groove on the posterior surface. The nostrils are situated in the concavity of the basal disc from which the nose-leaf springs. In this and the other species ofMegadermathere are no incisor teeth in the upper jaw (seefigure), the intermaxillary bone itself, which ought to bear these teeth, being represented only by a cartilaginous piece, which fills up the space between the canines; and the tail is exceedingly short, and contained in the basal part of the interfemoral membrane, which is large, and has its hinder margin concave, and not pointed as in most Bats.

TEETH OF THE LYRE BAT.

The great size of the ears and nasal appendages in these Bats has led Europeans in India to give them the name of Vampires, as they agree in these particulars with the true Vampire Bats of South America, and the name is certainly better applied to them than to the frugivorous Pteropidæ, which are sometimes called Vampires even by zoologists. It is, however, a singular fact that in both these groups the extraordinary developments of membrane about the head should be proved to co-exist with more bloodthirsty habits than are common to the Bats generally. It does not indeed appear to be absolutely made out thatMegaderma lyracondescends to partake of that insect diet which contents so many of its fellows. As Mr. Dobson remarks,“The very peculiarly-shaped, elongated, narrow muzzle and large trenchant canines, with acutely-pointed basal cusps (seefigure) of this and of the other species ofMegaderma, the projecting mandible and divided lower lip, so different from all Insectivorous Bats, naturally lead us to suspect corresponding differences in habits.” And he goes on to say that in examining the stomach and intestines of numerous specimens of the present species, he always found them either perfectly empty or filled with a pultaceous matter, in which no remains of insects were to be recognised. Mr. Hodgson, however, found insects in the specimens examined by him. But whether it contemns insects or not, an observation made by the late Mr. Blyth suffices to prove that higher forms of animal life, and indeed its own near relations, are exposed to its attacks. The account given by Mr. Blyth is so interesting that, although rather long, we may give it entire:—

“Chancing one evening,” he says, “to observe a rather large Bat enter an outhouse, from which there was no other egress than by its doorway, I was fortunate in being able to procure a light, and thus to proceed to the capture of the animal. Upon finding itself pursued, it took three or four turns round the apartment, when down dropped what at the moment I supposed to be its young, and which I deposited in my handkerchief. After a somewhat tedious chase, I then secured the object of my pursuit, which proved to be a fine female ofMegaderma lyra. I then looked to the other Bat which I had picked up, and, to my considerable surprise, found it to be a smallVespertilio, nearly allied to the Pipistrelle of Europe, which is exceedingly abundant, not only here, but apparently throughout India. The individual now referred to was feeble from loss of blood, which it was evident theMegadermahad been sucking from a large and still bleeding wound under and behind the ear; and the very obviously suctorial form of the mouth of the Vampire was of itself sufficient to hint the strong probability of such being the case. During the very short time that elapsed before I entered the outhouse, it did not appear that the depredator had once alighted; and I am satisfied that it sucked the vital fluid from its victim as it flew, having probably seized it on the wing, and that it was seeking a quiet nook where it might devour the body at its leisure. I kept both animals separate till next morning, when, procuring a convenient cage, I first put in theMegaderma; and after observing it for some time, I placed the other Bat with it. No sooner was the latter perceived than the other fastened upon it with the ferocity of a Tiger, again seizing it behind the ear, and made several efforts to fly off with it; but finding it must needs stay within the precincts of its cage, it soon hung by the hind legs to the wires of its prison, and after sucking its victim till no more blood was left, commenced devouring it, and soon left nothing but the head and some portions of the limbs.”

HEAD OF THE CORDATE LEAF BAT.HEAD OF THE AFRICAN MEGADERM.

HEAD OF THE CORDATE LEAF BAT.

HEAD OF THE AFRICAN MEGADERM.

According to Mr. Jerdon, the Lyre Bat frequents old buildings, pagodas, roofs of houses, and caverns, and is very abundant in the innermost chambers of the cave temples of Ellora and Ajunta. The same writer states that it has been known to eat Frogs and fish; indeed, Mr. Blyth also charges it with a particular fondness for Frogs, and says that on quiet evenings the Bats may be distinctly heard crunching the skulls and smaller bones of their amphibious victims.[178]

The other Oriental species, the Cordate Leaf Bat (Megaderma spasma, seefigure), very nearly resembles the preceding, both in colour and in general characters, but the posterior division of the earlet is larger and more acutely pointed, the nose-leaf, although similar, is shorter, and has the sides convex, and its concave basal disc is considerably larger. This species is an inhabitant of the whole Malayan region, of Ceylon, Java, Sumatra, Borneo, Celebes, Ternate, and the Philippine Islands.

The best known African species (Megaderma frons) is an inhabitant of the west coast of that continent, where it is found in Senegal and Guinea. In this Bat the ears and nasal appendage (seep. 289) attain even a greater development than inMegaderma lyra; the earlet is very long, especially the posterior division of it; the ears are united by their inner margin for about half their length; and the fur is of an ashy colour, with a faint yellowish tinge. A second AfricanMegadermahas been described by Professor Peters under the name ofMegaderma cor; it is from Egypt, and somewhat resemblesM. spasmain the form of its nose-leaf, but in other respects is more nearly related toM. frons.

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