Habits.—The Aye-Aye, whose name is derived from its call of "hai-hay," is one of the most singular of living animals. It was first discovered by Sonnerat during his travels in Madagascar in 1780, and by him sent to Paris. The skin remained unique in Europe for the best part of a century. Greatly owing to the superstitious dread in which the creature is held by the natives, it was for a long period, and is still, very difficult to procure, or to induce the natives to capture, specimens. Mr. Baron says that it is sometimes accidentally caught in traps by the natives, "but the owner of the trap, unless one of those versed in the Aye-Aye mysteries who know the charm by which to counteract its evil power, smears fat over it, thus securing its forgiveness and goodwill, and sets it free." In 1863 Dr. Sandwith sent a second example to Europe, the anatomy of whose body was made the subject of an exhaustive monograph by the late Sir Richard Owen. Since that date more than one specimen has been received alive, and its habits and constitution are now fairly well known. The Aye-Aye is entirely arboreal and nocturnal, sleeping during the day, with its body coiled round, lying on its side with its bushy tail spread over it as a covering. It suspends itself by its hind-limbs, and in this position it has been observed in captivity by Mr. Bartlett, using its hook-like finger to comb out its tail, to cleanse its face, the corners of its eyes, its nose, mouth, and ears, keeping meanwhile its other fingers closed. It lives in the depths of the forests, going about in pairs. Exquisitely keen of hearing, it can detect by sound the boring of insects within the dead branches of trees. Its attenuated wire-like finger acts as a probe to discover their position, and its powerful incisor teeth are used to cut down upon the tunnel of its prey, which consists principally of the Andraitra, the larva of a Beetle, which it then extracts with the same digit. The juices of plants are also supposed to form part of its food. It drinks after the manner of many Monkeys, by dipping its fingers into the water, and drawing them through its mouth. The Aye-Aye is fearless of Man, but in its wakeful hours, during the night, when irritated it can be very savage and strike out with its hands. The female produces but one young at a birth, and builds, in the fork of a tree, a ball-like nest, two feet in diameter, with an entrance hole in the side, forming it of the rolled up leaves of the Travellers'-tree, and lining it with small twigs and dry leaves. (Baron.)
THE TARSIERS. FAMILY TARSIIDÆ.
This family, like the preceding, has been constituted for the reception of two animals which are so remarkably distinct from all the other species of Lemurs, as to necessitate their being thus segregated. Between these two forms however, so close a relationship exists, that they have often been considered as only varieties of the same species. The family, therefore, consists, as in the Chiromyidæ, of a single genus, the characters of which constitute also those of the family.
THE TARSIERS. GENUS TARSIUS.
Tarsius, Storr. Prod. Method. Mamm., p. 32 (1780).
The Tarsiers are distinguished externally by the possession of a rounded head, and a very short, pointed muzzle; by their very large, long and naked ears, and eyes so remarkably large and protruding, as to form the most prominent feature of the face. The hind-limb, which is much longer than the fore-limb, is also very remarkable on account of the great elongation of the ankle-region (or tarsus) of the limb. The long and slender toes terminate in round, sucker-like discs, and are furnished with flat nails, except on the second and third toes, where the nails are merely compressed claws. The fore-limb, with or without the hand, is longer than the trunk; its digits also are long and slender (the third being longest, and the second equal to the fourth) and, like those of the foot, terminate in round sucker-like discs. Both the wrist and ankle are haired.
The long and Rat-like tail is longer than the body, and has a tufted termination. The skull presents enormous eye-cavities, the inner margins of the latter almost meeting in the centre. The orbits are nearly closed in from the temporal fossa by the union of the malar and alisphenoid bones—a character in which they differ from all other Lemurs, and approach the Anthropoid section of the Primates. Their dental formula is I21, C11, P33, M33 = 34. Of the upper jaw, the incisors are prominent and unequal, the anterior ones being larger than the posterior, and in contact in the middle line, thus leaving no central gap in the front of the jaw, as is the rule among Lemurs; the canines are about as long vertically as the inner incisor, and are smaller than the corresponding tooth in the True Lemurs; the pre-molars are canine-like, sharp, pointed, and furnished with a cingulum; the anterior pre-molar is smaller than the two others; the posterior pre-molar has one external and one internal cusp; the molars, all nearly equal in size, are wide transversely, strongly cingulate, and have two prominent external cusps. In the lower jaw, the solitary incisor in each half is small, and, instead of protruding horizontally, is nearly erect; the canines are also almost erect, and less like incisors than is usual in the Sub-order. The pre-molars are sharp, but the anterior is smaller than the two posterior; the anterior and median molars have four cusps, and are cingulate, while the posterior molar has five cusps.
The Tarsiers have nineteen dorsal and lumbar vertebræ together, and twenty-seven in the tail. The humerus presents a perforation (the entepicondylar foramen) at its lower inner side, and another nearly in the centre above the hinge. The femur is more than twice the length of the arm-bone; the lower half of the slender fibula is co-ossified with the tibia, while two of the tarsal, or ankle-bones (the calcaneum and naviculare), are remarkably elongated, thus giving to the hind-limb of these animals the singular conformation from which they derive their name. The large intestine is not convoluted upon itself as in so many of the Lemurs, nor is there a cæcum at the junction of its smaller and larger portions.
I. THE SPECTRAL TARSIER. TARSIUS TARSIUS.
Lemur tarsius, Erxl., Syst. Regn. Anim., Mamm., p. 71 (1777).