Popular Science Monthly/Volume 13/June 1878/The Pygmy Monkey

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THERE was lately presented to the London Zoölogical Society, by an engineer attached to the navigation service of the Upper Amazon, a monkey, which may be regarded as one of the smallest representatives of the order Quadrumana. The animal is not so big as a squirrel, its body measuring only fifteen centimetres, with a tail of about the same length. The tribe to which it belongs, that of the Hapalians, stands at the foot of the monkey series, at the head of which are the anthropoid apes. While the latter are remarkable for a stature nearly equal to that of the human species, a robust body without caudal appendage, and a voluminous brain with numerous convolutions, the Hapalians, on the other hand, in size do not surpass some of our Rodents. The body is rather slender, but covered with a heavy coat of hair, and terminated by a long tail; the brain is almost perfectly smooth. Like the Cebians, with which they constitute the Platyrrhine family, they have neither callosities nor cheek-pouches, but they differ from the other monkeys of the New World in the claw-like nails of all the fingers except the thumbs of the posterior members, and in the teeth, which number only thirty-two, the great molars being reduced to two on each side of each jaw. To these characters correspond notable differences in the habits and modes of life. Thus certain naturalists have supposed that the Hapalians (which they designate by the not very appropriate name of Arctopitheci—"bear-monkeys") must be regarded as an independent family, of the same rank as the families of the Platyrrhines and the Catarrhines. Even though we do not adopt this opinion, we are forced to admit that the Hapalians offer certain affinities with the Rodents, if not in the skeleton and the dental formula, at least in the gait. Like our squirrels, they are essentially arboreal, and run up and down the trunks of trees with great agility, buying their claws deep into the bark. Like the squirrels, too, they are lively and alert during the day, and spend the nights concealed in holes; like them, they shelter themselves against cold by gathering around them their bushy tails; like them, finally, they are exceedingly timid and wary, fleeing at the least noise, and seeking refuge in the foliage. But here the resemblance ends: for, while the Rodents, with their strong incisors and molars, easily cut and bruise the hardest grains and fruits, the Hapalians, whose jaws are of a different conformation, live on birds'-eggs, insects, fruits, and buds. As regards intelligence, the Hapalians appear to be far inferior to other monkeys, and in them the sense of touch in particular is poorly developed, the anterior members terminating in true feet, the digits of which are armed with claws, and the posterior members presenting only imperfect hands. The head is roundish; the flat face is animated with small but very bright eyes; the ears are often adorned with tufts of hair, which give an odd character to the physiognomy. Finally, the body is covered with a thick coat of soft, silken hair, often with regularly-arranged bands in the back and tail.[2] By

The Pygmy Monkey.

their aspect, and the coloration of their fur, by their size, by their mode of life, as also by the details of their organization, the Hapalians constitute a very natural family. Still, they may be divided into two genera, the Uistitis (Hapale or Jacchus), with long, tufted tail, with no fringe of hair around the face, but with tufts of hair on the ears; and the Tamarins (Midas), whose head is adorned with a fringe, but whose ears are more or less denuded. We will set this latter group completely aside, and consider only the Uistitis.

The species of the genus Jacchus, all, without exception, are found in tropical America, between the Isthmus of Panama and latitude 30° south, but chiefly, if not exclusively, in the region lying to the east of the Andes, some of them inhabiting the virgin forests, others the thickets scattered over the plains. The best-known species is the common Uistiti (Hapale or Jacchus vulgaris), with gray-russet pelt, with alternate red and blackish streaks, and with from fifteen to eighteen rings on the tail, a white, triangular spot on the forehead, and long white hairs on the sides of the head. It is a native of Guiana and Brazil, and was long ago described by Buffon, Illiger, and Geoffroy St.-Hilaire. It is of very small size, but a little larger than the pygmy monkey, recently acquired by the Zoölogical Society; its body measures from twenty to twenty-three centimetres, and the tail about fifty-five centimetres.

The common Uistiti is, no doubt, familiar to our readers, for it is often imported into Europe. It has even reproduced in captivity, and many naturalists, as Cuvier, Pallas, and Audouin, have made some very interesting observations on it. The young ones, which are born with the eyes open, have a very large head, a dark-gray skin of pretty uniform color, excepting the tail, which plainly shows the rings. Immediately after birth they cling to their dam, who, however, does not seem to have any great affection for them, and turns them over to the male as soon as she feels tired; he in turn gives them back to his consort when they try to suck. The adult animals, though they are by nature timid, become attached to those persons who care for them, and, though they do not exhibit much intelligence, they nevertheless appear to be able to associate ideas. Thus, one of the two Uistitis, which Audouin kept for a long time, acquired the habit of shutting the eyes whenever he ate grapes, and this because he had once squirted the juice of grapes into the animal's eyes. At the sight of a wasp this animal, as also its companion, was seized with sudden terror, and took refuge in the bottom of its cage, covering its head with its hands, though this was the first time it ever had seen that insect, and though it daily pursued flies with great address. Audouin, who had observed this occurrence, conceived the idea of offering to his two Uistitis not a live wasp, but a colored picture of one; to his great surprise, the monkeys fully recognized their enemy and manifested much alarm. Now, we know that most of our domestic animals, and even certain highly-organized monkeys, while they manifest pleasure or rage at beholding their own images in a mirror, are nevertheless perfectly indifferent in the presence of the portrait, however life-like, of an animal of a different species.

Pallas tells us that some Uistitis have endured perfectly well the winter cold of St. Petersburg, while, on the other hand, they were greatly incommoded by the heat of the summer. But this must be an exception, for, as a rule, in our menageries these little monkeys, despite all the care bestowed on them, have great difficulty in living through the winter season. They are fed mainly either on eggs, which they empty with much dexterity, or on fruit; the latter must be soft and sweet, for the Uistiti rejects almonds no less than acid fruits. Flesh meat has no attraction for them; and, when they seize with their hands a living bird, they first choke it to death and then tear open the cranium to get at the brain. Their cries are various: they express alarm by a sort of bark, anger by a short hiss, joy by a low cry, or by a rather pleasant purring. On the slightest opposition, they bristle the hair of their head and grit their teeth, and endeavor to bite the hand that would seize them. Nevertheless, it is but just to say that these inequalities of temper are seen rather in individuals captured at an advanced period of life than in those taken young. To capture these, the Indians wound or kill the mother, and then, without difficulty, seize the young ones, which she carries on her back.

Very nearly allied to the common Uistiti is the Hapale aurita, or eared Uistiti, with fur of russet black, streaked on the back with faint black bands; also the cowled Uistiti (Hapale humeralifer), with white face, surrounded with brownish hair, blackish body, a collar of snowy white on the scapular region, and tail bearing incomplete rings. These two species are, like Hapale vulgaris, natives of Brazil, and, like that animal, they are noticeable for the tufts of white hair which grow on the anterior surface of the ears. In other Uistitis, on the contrary (as the Hapale penicillata), and the white-headed Uistiti (Hapale leucocephala), which inhabit the same regions, the tufts on the ears are black. Finally, in the black-tailed Uistiti (Hapale melanura),of which, in all probability, Buffon's Simia argentata is only an albino variety, the hair, which is light brown, is very short, and the tail is of a uniform, light-brown color. To the same category belong the Pygmy Uistiti (Hapale pygmæa)—of which we give a figure copied from nature—and the white-footed Uistiti (Hapale leucopus), a species described last year by Gray, and which has the forearms, feet, and hands, of a nearly pure white color, while the rest of the body is brownish gray, with more or less mixture of red. This animal was discovered at Medellin, in Colombia; while the Hapale pygmæa—which differs from it both in markings and in size, having red spots and blackish streaks, and being much smaller than Leucopus—is confined to certain regions of Brazil and Peru.—La Nature.

  1. Translated from the French by J. Fitzgerald, A.M.
  2. The name Hapalians, given to these monkeys by Illiger, is derived from the Greek ἁπαλός, which means soft.