FOREST SCENE IN MADAGASCAR.
Dr. Sandwith wrote:—“After very great difficulty and much delay I have at length obtained a fine healthy male, a real Aye-Aye, and he is enjoying himself in a large cage which I had constructed for him. And now I have some questions to ask you. Do you want him dead or alive? It will, of course, be much easier to send his dead body home, if that will do; and if so, how am I to preserve him? If you want him alive you must tell me so without delay, as I think it would be dangerous to send him home in the cold season. I observe he is sensitive of cold, and likes to cover himself up in a piece of flannel, although the thermometer is now often 90° in the shade. He is a very interesting little animal, and from close observation I have learned his habits very correctly. On receiving him from Madagascar, I was told that he ate bananas, so of course I fed him on them, but tried him with other fruit. I found he liked dates, which was a grand discovery, supposing he be sent alive to England. Still I thought that those strong Rodent teeth, as large as those of a young Beaver, must have been intended for some other purpose than that of trying to eat his way out of a cage—the only use he seemed to make of them besides masticating soft fruits. Moreover, he had other peculiarities, e.g., singularly large naked ears, directed forward as if for offensive rather than defensive purposes; then again the second finger of the hands is unlike anything but a monster supernumerary member, it being slender and long, half the thickness of the other fingers, and resembling a piece of bent wire. Excepting the head and this finger, he closely resembles a Lemur. Now, as he attacked every night the woodwork of his cage, which I was gradually lining with tin, I bethought myself of tying some sticks over the woodwork, so that he might gnaw these instead. I had previously put in some large branches for him to climb upon; but the others were straight sticks to come over the woodwork of his cage, which alone he attacked. It so happened that the thick sticks I now put into his cage were bored in all directions by a large and destructive grub called here the Montorek. Just at sunset the Aye-Aye crept from under his blanket, yawned, stretched, and betook himself to his tree, where his movements were lively and graceful, though by no means as quick as those of a Squirrel. Presently he came to one of the worm-eaten branches, which he began to examine most attentively; and bending forward his ears and applying his nose close to the bark, he rapidly tapped the surface with the curious second digit, as a Woodpecker taps a tree, though with much less noise, from time to time inserting the end of the slender finger into the worm-holes as a surgeon would a probe. At length he came to a part of the branch which evidently gave out an interesting sound, for he began to tear it with his strong teeth. He rapidly stripped off the bark, cut into the wood, and exposed the nest of a grub, which he daintily picked out of its bed with the slender tapping finger, and conveyed the luscious morsel to his mouth. I watched these proceedings with intense interest, and was much struck with the marvellous adaptation of the creature to its habits, shown by his acute hearing, which enables him aptly to distinguish the different tones emitted from the wood by this gentle tapping, his evidently acute sense of smell aiding him in his search; his secure footsteps on the slender branches to which he firmly clings by his Quadrumanous members; his strong Rodent teeth enabling him to tear through the wood; and, lastly, by the curious slender finger, unlike that of any other animal, and which he used alternately as a pleximeter, a probe, and a scoop. But I was yet to learn another peculiarity. I gave him water to drink in a saucer, on which he stretched out a hand, dipped a finger into it, and drew it obliquely through his open mouth; and this he repeated so rapidly that the water seemed to flow into his mouth. After a while he lapped like a Cat; but his first mode of drinking appeared to me to be his way of reaching water in the deep clefts of trees. I am told that the Aye-Aye is an object of veneration at Madagascar, and that if any native touches one he is sure to die within the year; hence the difficulty of obtaining a specimen. I overcame this difficulty by a reward of ten pounds.”
Further information on the same subject was obtained by M. Vinson, who states that his Aye-Aye slept the greater part of the day, and moved about and made attempts to escape at night time. Having once succeeded, it climbed to the nearest tree, and moved about, leaping from branch to branch with the agility of the Ring-tailed Lemur; but its ordinary life in captivity suggested the idea of its being an indolent and rather slow-moving animal. The tail is carried in a curve, with the hollow of the bend downwards, so that it is slightly arched, and its chief office seems to be to add to the warmth of the already warm fur when the animal is in repose. In assuming the attitude of rest, the Aye-Aye places its head between its hands, and bends the tail over it by curving it forwards and letting it fall. Then it rolls itself into a ball, and covers the whole surface with the bushy hairs of this useful appendage, which is longer than the whole body and head together.
With regard to the Aye-Aye mentioned by Dr. Sandwith, Owen advised that, if it could not be sent safely to England, it had better be killed by chloroform, and sent over in spirit. Before this advice arrived the animal managed to escape from its confinement, and made for the sugar-canes in a neighbouring plantation, and there the unlucky Aye-Aye was speedily captured. He was martyred for the sake of science, and its description by Owen will last as long as literature, and its skin and bones as long as the British Museum exists. Some other observers had interested themselves about the animal in the interval, and in 1855 M. Liénard is said by Owen to have observed the habits of a young male. This one liked mango nuts, and invariably made a hole in the rind with his strong front teeth, inserted therein his slender middle digit, and then lowering his mouth to the hole, put into it the pulp which the finger had scooped out of the fruit. When one hand was tired it used the other, and often changed them. On presenting him with a piece of sugar-cane, he held it by both hands, and tearing it open with his teeth, sucked out the juice. M. Vinson had one for two months, which was brought from Madagascar to the Ile de la Réunion, and he stated that it selected the grubs it liked best by the sense of smell, and that when café au lait or eau marée was offered, it drank by passing its long slender finger from the vessel to the mouth with incredible rapidity.
The Aye-Aye, according to the discovery of M. Soumagne, honorary consul of France in Madagascar, constructs true nests in trees, which resemble enormous ball-shaped “birds’-nests.” He found them in the belt of forest which is situated half-way up a great mountain close to the town of Tamatave. They are composed of the rolled-up leaves of the so-called “Traveller’s Tree,” and are lined with small twigs and dry leaves. The opening of the nest is narrow, and is placed on one side, and it is lodged in the fork of the branches of a large tree. In this the Aye-Aye resembles the lower Lemuroids, and not the genera Loris and Tarsius.
The specimen of the Aye-Aye examined by Owen is three feet in length, the included tail measuring one foot eight inches and a half, and the fourth fingers of the hand and the fourth toes are the longest. The forefinger is shorter than the fifth, or little finger, and the second toe, counting the toe-thumb as the first, is shorter than the little toe.
The Aye-Aye is admirably adapted for its peculiar life, although part of its construction is very unlike that of the other Lemuroids, whose habits are much the same. Having nocturnal habits, the eyes are especially formed for the purpose of admitting all the light possible. They are large, prominent, and none of the “white” or conjunctiva is seen, only the cornea and the light brown or hazel-coloured iris behind it (commonly called the “sight”) being visible. It is a very staring, open eye, and the pupil is capable of being widely opened in the dark, and in fact it dilates generally as the light wanes, so as to admit every possible ray. In daylight, on the contrary, it contracts to a pin’s point in size, so as to shut out the light which would dazzle the eye and probably produce injury to it. There is a tapetum (see [page 214]) which assists in nocturnal vision. Nature has protected the eye not only with lids, for there are traces of eyelashes on the upper one but not on the lower, under which, however, there are some bristles. There is a kind of eyebrow in the form of tufts of a dozen very slender bristle-like hairs, and to complete the arrangement for protecting the eye against direct injury, and for letting the animal know when things are near enough to injure its organ of sight, there is what is called a nictitating fold in each eye. This is a layer of the white of the eye, or conjunctiva, situated close to the inner side near the nose, and which extends when required over the “sight” as a cover and protection. In addition to the nocturnal sight, the Aye-Aye has evidently extremely delicate hearing, the ears being large, spoon-shaped, and open, and their sense is very acute. For, either by hearing or by their very fine sense of smell, it detects grubs in the wood, and soon has them out, thanks to its teeth and claws.
The feet are long, and are made for grasping and for supporting the Aye-Aye on boughs whilst it uses its hands and teeth. They are very strong, and have a very long ankle, and claws to all the toes, except to the great thumb-like toe, which is very powerful, and has a flat nail. But it is in the hands and teeth that the singularity of the animal is made manifest, which makes it so little like the Lemuroida as a group. The hand is unique, but the front of the skull and the front teeth resemble those of the gnawing animals, and hence the name Cheiromys, which means hand-rat. Something has been said already regarding the food of the animal, and as its nature has to do with the hands and teeth, it is advisable to quote the able Superintendent of the Zoological Gardens, Mr. Bartlett:—
“In feeding,” writes Mr. Bartlett, “the left hand only is used, but the examination of the mode of taking her food requires careful attention, owing to the very rapid movement of the hand. The fourth finger, which is the largest and longest, is thrust forward into the food; the slender third finger is raised upwards and backwards above the rest, while the first finger (or thumb) is lowered so as to be seen below and behind the chin. In this position the hand is drawn backwards and forwards rapidly, the inner side of the fourth finger passing between the lips, the head of the animal being held sideways, thus depositing the food in the mouth at each movement. The tongue, jaws, and lips are kept in full motion all the time. Sometimes the animal will advance towards the dish and lap like a Cat, but this is unusual. The skeleton-like third finger is used with great address in cleansing her face and picking the corners of the eyes, nose, mouth, ears, and other parts of the body, and during these operations the other fingers are closed.” From all that has hitherto been observed, the Aye-Aye evidently eats both insects and vegetable food, so that in captivity it will reject meat food more or less. In its natural state it will prefer the grubs of some trees to those which frequent others, and it searches along the boughs for some evidence of their presence, and, with teeth and slim fingers, opens their galleries and brings them to light.
The teeth are certainly remarkable. There are two sets, the milk teeth and the adult teeth. In the first, or milk teeth, there are two front teeth, one canine tooth, and a molar or grinder on each side of the upper jaw. In the lower jaw there is but one front tooth, no canine, and one molar on each side. A further peculiarity consists in the falling out of the molars, one incisor, and the canine in the upper jaw, to be replaced by the following adult dentition, or second set. This consists of one incisor, no canine, one pre-molar, and three molars on both sides of the upper jaw; while below, the canine and pre-molar are entirely absent, the incisor and molar being like those of the upper jaw; it has thus eighteen teeth altogether. There are two front teeth in the upper and two in the lower jaw only, but they are very large, long, and narrow, being shaped like those of a Rabbit or Rat. Their tips wear away and expose a sharp cutting surface of thick enamel in front, and they are splendid cutting chisels. They gnaw and cut away wood, strip off bark, and make deep holes in the branches, and their length permits them to be placed in hollows in the wood so as to prise them open by acting as levers. It appears that they are made to grow from their sockets as they are worn down by frequent use. They are by themselves, and there is a great gap (diastema) or distance in the gums between them and the next teeth. This is quite after the fashion of the gnawing animals. The back teeth crush and champ fruit, vegetable substances, and insects with ease. There is a curious point about the chin, for there is no bony union there between the two sides of the lower jaw; on the contrary, the union is by a more or less elastic tissue, which permits of some movement up and down and from side to side during the action of the great front teeth.[144]