574 



SCIENCE, 



THE AYE-AYE OR CHEIROMYS OF MADA- 

 GASCAR. 



During the present year the Menagerie of the Botanical 

 Garden has been enriched by the addition of several rare 

 animals, and among others, by that of three Lemurs of 

 Madagascar belonging to the strange species commonly 

 called Aye-Aye, and scientifically Cheiromys Madagas- 

 cariensis. The Museum of Natural History already 

 possessed in its collection, not only the same species, 

 obtained more than a century ago, by the explorer 

 Sonnerat, but also several specimens preserved in alcohol 

 or reduced to skeletons, which have been presented at 

 more recent dates by M. de Lastelle, M. A. Grandidier 

 and M. Meurand. The study of these different specimens 

 and of those which the British Museum has procured, 

 has at length led naturalists to the discovery of the true 

 affinities of the Aye-Aye, and has decided the place it 

 should occupy in classification, namely in the order of 

 Lemurs. But, before coming to this conclusion, there 

 was a great deal of hesitation and groping in the dark. 

 Sonnerat, who discovered the Aye-Aye in Madagascar, 

 considered it a squirrel having some connection with the 

 Makis, soon after, Buffon found in it certain resemblances 

 to the Tarsier, then Gmelin placed it decidedly in the 

 genus Sciurus or Squirrel, under the name of Sciurus 

 Madagascar iensis \ later still, E. Geoffroy Saint-Hilaire 

 made a particular genus for this strange animal, namely 

 Daubentonia, which G. Cuvier, agreeing with Geoffroy, 

 afterwards changed to Cheiromys ; finally Blainville main- 

 tained that the Aye- Aye belonged to the order of Lemurs, 

 and he was successful, though not without difficulty, in 

 establishing his views. 



The Aye-Aye has nearly the height of a cat and re- 

 sembles in a slight degree the Feline tribe in its short 

 and globular head, erect and uncovered ears, eyes very 

 open, nostrils oblique and pierced at the extremity of the 

 nose, although it resembles a Squirrel in its slender toes, 

 the color of the hair, and its bushy tail. But it differs 

 entirely from both of these animals by the arrangement 

 of its paws. In the Aye-Aye, indeed, the posterior limbs 

 terminate as in the great majority of the Lemurs, in real 

 hands, the thumb, however, being a little less developed 

 than in the latter animals, and the anterior limbs present, 

 at their extremities, singular anomalies. Here the thumb 

 is no longer opposable to the other fingers and it carries, 

 as the latter, a true claw, the middle finger is so slender 

 that it seems withered, the fourth finger is a little less 

 slender but still larger than the other, and finally, the 

 little finger is very extended. 



The dentition of the Aye-Aye differs in several respects 

 from that of the other Lemurs ; there are, indeed, two 

 strong and sharp incisors in each jaw, four molars on 

 each side of the superior maxillary and three molars only 

 in the inferior maxillary ; but no trace of canines, super- 

 ior or inferior, can be seen in the adult, so that a wide 

 space separates the incisors from the molars. Yet, this 

 anomaly does not exist to the same degree at all periods 

 of life, and, in the young, the dental system is least re- 

 moved from the ordinary type, owing to the presence, 

 in the superior maxillary, of a pair of small incisors. 



Arrived at its full development, the Aye-Aye measures 

 more than a metre from the end of .the nose to the ex- 

 tremity of the tail, whose length is about equal to that of 

 the body. It has smooth and slightly wart-like ears, un- 

 covered nose, and lips ordinarily half open, exposing to 

 view the incisors which, meeting two by two in a very 

 prominent angle, resemble the beak of a parrot. Hair, 

 bushy and very long, covers the whole of the body, the 

 limbs and the tail, but does not present in every spot a 

 uniform color; the hairs of the head and of the back are 

 often white at their ends, while those of the breast and 

 of the flanks are of a more or less brown, deepened by a 

 yellow base. In the young, the whole front is also of a 

 silvery white, and the dorsal line is marked by a band of 

 the same color. 



In Sonnerat's "Voyage aux Indes et a la Chine," some 

 of the principal characteristics of the Aye-Aye are spoken 

 of, but the portrait leaves much to be desired, and the 

 author mentions but a few things on the habits of this 

 curious representative of the fauna of Madagascar. This 

 animal, says Sonnerat, appears to burrow, it does not see 

 in the day, its eye is reddish and fixed like that of a 

 screech-owl. It is very lazy and, consequently, very gentle. 

 I have had the male and female and they lived only 

 two months. I fed them with boiled rice, and they used 

 in eating, the two slender toes of the fore-feet as the 

 Chinese use chop-sticks. They are timid, fearful, like 

 a great deal of heat, always roll themselves up in sleep- 

 ing, lie on the side, the head between the fore-limbs. 

 They were always lying down, and it was only on shak- 

 ing them several times, that they would move at all. 



Although this animal is very slow in movement, and 

 seems to be torpid during the day, it ha-s no relation to the 

 Unau and the Ai of M. de Buffon. The name of Aye- 

 Aye, which I have kept for it, is a cry of exclamation and 

 astonishment among the inhabitants of Madagascar. 

 This animal has been known to us but for a few years, 

 because the western side, the part which it inhabits, is 

 but little frequented ; the inhabitants of the eastern side 

 assured me that it was the first they had ever seen. 



Fortunately, the successive observations on the 

 Cheiromys at the Zoological Gardens at London and at 

 Paris have completed the information given by Sonnerat 

 on the manners and the diet of this species. The Aye- 

 Aye is essentially a nocturnal animal ; in captivity, it 

 sleeps during the whole day, lying on the side, its body 

 curled up and entirely covered by the bushy tail. During 

 the night, on the contrary, it moves about continually, 

 scratching and gnawing the walls of its prison. Fre- 

 quently it hangs by its hind claws, and, in this position, 

 it performs its toilet in the manner of certain Bats. 

 In this operation it uses the third finger of the fore-feet, 

 which it bends in the form of a hook in order to comb 

 the tail and to adroitly wipe its front, the corners of its 

 eyes, the nose, mouth and ears. 



In eating, the Aye-Aye exclusively employs the left 

 hand ; it thrusts into the semi-liquid food which is given 

 to it, the fourth finger, the longest of all. holding the 

 third raised above the others, and the thumb, on the other 

 hand, very low. The extremity of the anterior limb, thus 

 arranged, describes a singularly rapid motion to and fro, 

 and the lateral face of the fourth finger, passing every 

 moment between the lips of the animal whose head is in- 

 clined on one side, places the food in the buccal cavity, 

 over the tongue. At the same time, the cheeks and lips 

 are in continual motion. "The Aye-Aye," says Mr. 

 Bartlett, " can also advance its lips and lick in the man- 

 ner of cats ; but it does this but rarely. I have never 

 heard it utter a single cry, emit any sound, during the 

 long hours of night, and I never have observed that he 

 was made uneasy by my presence. This Lemur seeks no 

 species of insects, but readily feeds on a sort of pap made 

 of milk, honey and eggs ; it appears to love semi-fluid 

 substances, soft and mucilaginous, while it rejects with 

 contempt •Worms, grass-hoppers, and the larva of hymen- 

 opters. I have then the right to state that, in a state of 

 nature, the Aye-Aye is not insectivorous. Seeing its 

 strong and sharp teeth, I am inclined to believe that it 

 cuts grooves in the bark of trees, in order to make the sap 

 flow ; it receives this in its mouth and it forms its princi- 

 pal nourishment. In support of this opinion, I state the 

 fact that the animal frequently returns to the same spot 

 on the branch or on the trunk, which it first attacked. 

 It must also be stated that the Aye-Aye pays, so to 

 speak, no attention to what it carries to its mouth. Hav- 

 ing on several occasions withdrawn the dish which con- 

 tained its pap, while it was eating, I saw with astonish- 

 ment that it continued to direct its hand towards the spot 

 where its food had been, and that it did not search for 

 the latter until after having, for a long time, mechani- 



