Handbook to the Primates/Pitheciinae

The Sakis are characterised by having their lower incisor teeth inclined forward at their summits somewhat as among the Lemurs; and separated from the long canines by an interspace. The molar teeth are small; the tail, which in some is long, in others short, is non-prehensile. The nostrils are, as usual, far apart, and the thumb is well developed. The ears are large. Great differences in the character of the fur exist in the group: some species having long hair over the whole body, others on the chin and cheeks; some are well bearded, while others again are quite bald.

The Sakis are divided into two genera, a short-tailed group (Brachyurus), containing the Uakarí Monkeys, and a long-tailed section, the Sakis (Pithecia). Their various species are restricted to the great equatorial forests of South America.

The species of this genus are at once recognised by their short tail, being the only American Monkeys in which this organ is short. The fur is short and silky; the face short, and often brightly coloured. The mammæ are situated on the breast. In the skull the lower jaw is dilated behind, and certain bones, the parietal and the malar, are in contact with each other for a more or less considerable extent on the side walls of the skull. (Cf. W. A. Forbes, P. Z. S., 1880, p. 639, figs. 5 and 6.) In Old World Monkeys this contact never (except slightly in Hylobates) takes place. This is a useful mark for discriminating between the skulls of New and Old World Monkeys. (Forbes.) The shortness of the tail is due, not to a reduction in the number of the vertebræ, which may be 15 to 17, but in their size.

In the brain the cerebrum exhibits the more important grooves characterising the brain of the higher Apes (Simiidæ) well developed; the cerebellum (or hind brain) is also well developed. Thus in its general characters the brain of the Uakarís approaches most nearly to that of the genera Cebus and Pithecia (next to be described). By reason of its greater complication and development, it departs widely from that of the Titis (Callithrix) and the Squirrel-Monkeys (Chrysothrix).

A relationship to the Howlers (Mycetes), suggested by the external appearance of the Uakarís and the form of their lower jaw, is not borne out by their internal anatomy. The caudate lobe of the liver is very large. This character distinguishes the whole of the Cebidæ from the Old World families.

The Uakarís are arboreal Monkeys, very gentle and timid. The distribution of the various species is singularly restricted, each being confined to a small and particular district.

Characters.—Head and nude face-black; back, sides, thighs, upper surface of tail, and outer and inner sides of legs more or less chestnut-brown; shoulders, arms, hands, feet, and rest of tail, black. Ears large, naked, and similar in form to those in Man.

Distribution.—Confined, so far as at present known, to the forests traversed by the Rio Casiquiare, Rio Negro, and Rio Branco. This is the most northern form of the three species of the genus, and apparently the most widespread also (see map, p. 180). This is doubtless the "black-faced, grey-haired" species, neither white nor red, which Mr. Bates was assured took the place of B. calvus, at 180 miles northward from the mouth of the Japurá.

Habits.—Living in the high trees of the forest, feeding on fruits; and not differing in habits from those of the other species of the genus, which are referred to below.

Characters.—Face, chin, lips, forehead, and sides of face, bare (except for a few superciliary hairs, and scant representatives of moustache and beard), all bright vermilion red, deepening with emotion. Eyes brown; ears square in shape, without a lobule; hair on top of head short, silky, and grey; that on the side of the lower jaw and throat long and rich chestnut-red, running forward as far as the symphysis, and forming whiskers. Hair of upper surface of body entirely rich chestnut-red, more or less black-tipped and long, especially on the shoulders and limbs; hair of head, nape, and neck paler than on the rest of the body; tail, haired below at tip, rich chestnut-red; under surface of body rich chestnut-red, and less hairy. The fur in general colour and texture resembles that of the Orang, the red hair, continued on to the limbs and tail, being particularly long on the arms and shoulders (forming a sort of cape), and along the hind border of the thigh and leg. (W. A. Forbes). Between the thigh and the lower part of the leg there is a wide expansion of the skin behind the knee.

The thumb is in the same plane with the other digits and not opposable; digits with compressed and rather elongated nails; the nail of the thumb and the great-toe shorter and more "nail"-like; upper surface of the hands and feet haired, on to the fingers. The cæcum (6 inches) and intestines (22 inches) are absolutely and relatively longer than in any other New World Monkey.

Length of the body, 27-28 inches; of the tail, 6½

Distribution.—Forests on the north bank of the Amazons, opposite Olivença, not passing eastwards of Iça on the Iça river. The exact westward extension of this species still remains unknown. The young specimen seen at Fonteboa by Bates, and by him referred to this species, was more probably B. calvus, as we know from the account given by Geoffroy St. Hilaire and Castelnau, that the young of B. rubicundus resembles in coloration the adult, and is not paler.

Habits.—Gregarious and diurnal; living in the high trees, and feeding on fruits, probably exclusively, the length of its intestines seeming to indicate that it is more of a vegetarian than its allies.

Characters.—Fur very long, straight, and shining from neck to tail. Face scarlet; top of head nearly bald, greyish, passing into brown anteriorly and at the sides, with bushy sandy whiskers meeting below the chin; throat dark brown, mixed with numerous black hairs, the general tint being rich chestnut-brown; back whitish-grey, with black hairs mixed with white ones, which are in greater number. Under surface fulvous brown, darker on the breast, where brown hairs are numerous; the same brown tinge is visible on the arms, legs, the hinder region of the thighs, at the wrist, and ankle, and especially on the tail; eyes reddish-yellow. Length, 18 inches.

Some species are paler than the above description, being pale sandy-white, slightly rufous below and on the inside of the limbs.

Cæcum 10 inches long along its greater curvature, and not sacculated.

According to Mr. Beddard, B. calvus and B. rubicundus agree very closely in external and in internal characters, while B. melanocephalus differs more in external characters from the other two than they do from each other.

Distribution.—Opposite Fonteboa; banks of the Japurá river west of its mouth. This species appears to be confined to the triangle formed by the union of the Japurá river and the Amazon. It does not pass east of Ega, nor does it cross to the south of the Amazon, but keeps to the forests of the low lands to the north of that boundary and south of the Japurá.

THE BALD UAKARI.

Habits.—"This scarlet-faced monkey," says Mr. Bates, "lives in forests, which are inundated during the greater part of the year, and is never known to descend to the ground; the shortness of its tail is, therefore, no sign of terrestrial habits, as it is in the Macaques and Baboons of the Old World.... It seems to be found in no other part of America than the banks of the Japurá near its mouth; and even there it is confined to the western side of the river. It lives in small troops amongst the crowns of the lofty trees, living on fruits of various kinds. Hunters say it is very nimble in its motions, but it is not much given to leaping, preferring to run up and down the larger boughs in travelling from tree to tree. The mother, as in other species of the Monkey order, carries her young on her back. Individuals are obtained alive by shooting them with the blow-pipe and arrows tipped with diluted Urari poison. They run a considerable distance after being pierced, and it requires an experienced hunter to track them. He is considered the most expert who can keep pace with a wounded one and catch it in his arms when it falls exhausted. A pinch of salt, the antidote to the poison, is then put in its mouth, and the creature revives.... Adult Uakarís, caught in the way just described, very rarely become tame. They are peevish and sulky, resisting all attempts to coax them, and biting anyone who ventures within reach. They have no particular cry, even when in their native woods; in captivity they are quite silent. In the course of a few days or weeks, if not carefully attended to, they fall into a listless condition, refuse food, and die.... The bright scarlet of its face is, in health, spread over the features up to the roots of the hair on the forehead and temples, and down to the neck, including the flabby cheeks, which hang down below the jaws.



The animal, in this condition, looks at a short distance as though someone had laid a thick coat of red paint on its countenance.... After seeing much of the morose disposition of the Uakarí, I was not a little surprised one day, at a friend's house, to find an extremely lively and familiar individual of the species. It ran from an inner chamber straight towards me after I had sat down on a chair, climbed my legs and nestled in my lap, turning round and looking up with the usual Monkey's grin after it had made itself comfortable. It was a young animal, which had been taken when its mother was shot with a poisoned arrow; its teeth were incomplete, and the face was pale and mottled, the glowing scarlet hue not supervening in these animals before mature age; it had also a few long black hairs on the eyebrows and lips. The frisky little fellow had been reared in the house among the children, and allowed to run about freely...." This species is rare, even in the limited district which it inhabits. A Government official sent six of his most skilful Indians, who were absent hunting for three weeks before they obtained twelve specimens.

In reference to the singularly restricted range of these Uakarís, Mr. Wallace's observations in his paper "On the Monkeys of the Amazon," before the Zoological Society of London, are of great interest.

"During my residence," he says, "in the Amazon district, I took every opportunity of determining the limits of species, and I soon found that the Amazon, the Rio Negro, and the Madeira formed the limits beyond which certain species never passed. The native hunters are perfectly acquainted with this fact, and always cross over the river when they want to procure particular animals, which are found even on the river's bank on one side, but never by any chance on the other. On approaching the sources of the rivers, they cease to be a boundary, and most of the species are found on both sides of them. Thus several Guiana species come up to the Rio Negro and Amazon, but do not pass them; Brazilian species, on the contrary, reach but do not pass the Amazon to the north. Several Ecuador species from the east of the Andes reach down into the tongue of land between the Rio Negro and Upper Amazon, but pass neither of those rivers, and others from Peru are bounded on the north by the Upper Amazon, and on the east by the Madeira. Thus there are four districts whose boundaries on one side are determined by the rivers I have mentioned. In going up the Rio Negro, the difference on the two sides of the river is very remarkable.

"In the lower part of the river you will find on the north the Jacchus [Hapale] bicolor, and the Brachyurus couxui [Pithecia satanas], and on the south the red-whiskered Pithecia. Higher up you will find on the north the Ateles paniscus, and on the south a black Jacchus and the Lagothrix humboldtii."

The Sakis form the second section of the present Sub-family, and are characterised by their long, thick, and bushy non-prehensile tail. A thick beard conceals the large chin. Hair on the crown long, divided by a central line, and hanging over the head, half concealing the pleasing diminutive face, or confined to the head, cheeks, and chin. The ears are large. The upper and lower incisor teeth project forward, the upper inner pair being moderately large, the outer very small; canines strong and conical; first pre-molar smaller than the others, and one-cusped; molars with square crowns, grooved in the middle and slightly four-cusped.

In the brain the whole of the cerebellum and the olfactory lobes are covered by the cerebrum. In general form the latter resembles that of the species of Cebus. The frontal and occipital regions of the skull approximate in form to those in Man; the angle of the mandible is expanded, but less so than among the Howlers (Mycetes). The ribs are relatively broader in this genus than in any other of the American Monkeys.

Characters.—Fur harsh, long and loose, with a hood of forwardly-directed hairs on the upper part of the head, neck, and shoulders. Face bare, long, and narrow; nose large and full; nostrils widely separated and lateral. Face dark purplish-brown, and black on the nose, paler round the eyes, and sparingly covered with short coarse whitish hairs; a yellowish-white patch on the cheeks, terminating in front in a distinct line from the inner corner of the eye to below the angle of the mouth; margin of upper lips white; ears large, round, naked, and of the same colour as the face; upper part and back of head, neck, shoulders, back, arms, thighs, and tail, black, washed with yellowish-white, becoming yellowish-brown on the hinder part of the body. Throat, breast, under side of body, and inside of thighs, pale yellowish-brown, sparingly haired. Tail 18 inches long, cylindrical, and bushy at the end; the hair long, coarse, curled, black, washed with pale yellowish-brown. Legs black; fore-arm black, washed with white; upper surface of hands, feet, and digits, white. Hands small, thumbs short, parallel to the other fingers; nails black, somewhat compressed, pointed, that of the thumb flatter; great-toe well developed, standing apart from the other toes, its nail flat and pointed; nails of the other toes long, curved, and compressed.

Distribution.—Mr. Bates states that the "Parauacú," as this Monkey is called by the natives of its own country, is found on the "terra firma" lands of the north shore of the Solimoens, or Upper Amazon, from Tunantins to Peru. It exists also on the south side of the river on the banks of the Teffé, but there under a changed form, which differs from its type in colours, as much as the red differs from the white Uakarí. This variety is Dr. Gray's Pithecia albicans.

Habits.—The Hairy Saki is a very timid and inoffensive animal, and is also, as Mr. Bates tells us in his well-known book, "very delicate, rarely living many weeks in captivity; but anyone who succeeds in keeping it alive for a month or two, gains by it a most affectionate pet. One of the specimens now in the British Museum was, when living, the property of a neighbour of mine at Ega. It became so tame in the course of a few weeks that it followed him about the streets like a dog. My friend was a tailor, and the little pet used to spend the greater part of the day seated on his shoulder whilst he was at work on his board. It showed, nevertheless, great dislike to strangers, and was not on good terms with any other member of my friend's household than himself.... The eager and passionate Cebi seem to take the lead of all the South American Monkeys in intelligence and docility, and the Coaita, one of the Spider-Monkeys (Ateles paniscus), has, perhaps, the most gentle and impressionable disposition; but the Parauacú, although a dull, cheerless animal, excels all in this quality of capability of attachment to individuals of our own species, nor is it wanting in intelligence."

Characters.—Male.—Hair black, very long over the body, and especially on the tail. Head with short hair, white, washed with yellow and divided by a central nude black streak; the white hair becoming yellow on the cheeks.

Female.—Greyish-black, washed with pale yellow, the hairs being tipped with the latter colour; moustache yellow; belly red.

Young Male.—Belly rufous brown.

Distribution.—Interior of Demerara, Kaicteur Falls; Rio Negro, and Rio Branco in Amazonia; Cayenne; Surinam.

Characters.—Male.—Fur soft; tail bushy and as long as the body; crown with long black hair arranged on each side, divided by a central line. "The hair of the head sits on it like a cap, and looks as if it had been carefully brushed." (Bates.) Long whiskers on each side, and the chin with a moderate beard. Fur black and shining; back sometimes washed with grey or ashy-brown.

Female.—Similar to the male, but having a browner back.

Young.—Beard absent or rudimentary; hair of crown radiating from centre and projecting forwards.

The skull in this species is sometimes ossified into one piece.

Distribution.—Lower Amazonia; Para; British Guiana; the River Orinoco, towards the Rio Negro.

Habits.—Little is known of the habits of the Black Saki, which is also known under the names of "Cuxio" and "Mono Capuchino." It lives in the most retired parts of the forest, where the ground below it is not inundated by the river, and feeds on fruits.

It is said that this animal—unlike the next species—drinks freely, always bending down on its hands and putting its mouth to the surface of the water, heedless of wetting its beard and indifferent to the observation of onlookers. Sir Robert Porter says that he never saw it take up water in the hollow of its hand, and convey it to its mouth to drink. Its voice is a weak and chirping whistle, which becomes shrill and loud when the animal is angry.

A young male of this species, which died in the Zoological Society's Gardens in 1882, presented an abnormal condition. The peculiarity consisted, as Mr. W. A. Forbes, the late distinguished prosector to the Society, has pointed out in the "Proceedings," in the completely "webbed" condition of the third and fourth digits of the manus (hand) on each side, these two fingers being completely connected together, down to their tips, by a fold of nude skin, and with their nails closely apposed, though not connected along their contiguous margins. The other digits of the hands, as well as those of the feet, were quite normal, the webbing not extending beyond the middle of the first phalanx. Mr. Forbes remarks: "The case is interesting, partly as affording an excellent instance of an abnormal condition affecting homologous parts of opposite sides in an exactly similar way, and partly as showing that the lower Primates are subject, occasionally, to a condition of things which, as is well known, also occurs not at all rarely in Man."

Characters.—Male.—Larger than P. satanas; black, with a reddish-chestnut patch on the back, with a coarse brownish beard, longer than in P. satanas; tail very thick, bushy.

Female.—Similar to the male, but without the beard.

Distribution.—Amazonia, Rio Negro, and Rio Branco; Upper Orinoco; British Guiana.

Habits.—This species is said to be solitary, or to go about only in pairs. It derives its scientific name from its habit of drinking by lifting the water to its head with its hands, instead of stooping down and applying its mouth to the water. It is difficult to tame, being fierce and ill-dispositioned.

THE WHITE-NOSED SAKI.

Characters.—Uniformly, but rather sparingly, covered with black hairs. Face black, naked; nose broad and naked, and with a bright scarlet line down its bridge, broadening out on the latter and on the upper lip; tip of nose white, from the presence of a few white hairs.

Long hairs on the head falling to all sides; tail long and clothed to the tip with long hairs hanging down from its under side, slightly prehensile. Length of the body, 15 inches; of the tail, 18 inches.

Distribution.—Amazonia.

Habits.—The White-Nosed Saki, which might much more appropriately have been called the "Red-Nosed Saki," is very rare; its habits are quite unknown. The type specimen in the Paris Museum remained unique in Europe from 1848 till 1881, when a living specimen was brought to the Zoological Gardens in London.