Chapter III: The Bald Uakarí. Brachyurus Calvus

_Brachyurus calvus_, Is. Geoffr., C. R., xxiv., p. 576 (1847); id., Arch.
Mus., v., p. 560 (1845); Castelnau, Expéd. Amér. Sud, Mammif., p. 17, pl.
4, fig. 1 (1855); W. A. Forbes, P. Z. S., 1880, p. 646; Beddard, P. Z.
S., 1887, p. 119, pl. xii.

{178}_Ouakaria calva_, Gray, Cat. Monkeys Brit. Mus., p. 62 (1870).

_Pithecia calva_, Schl., Mus. Pays Bas, vii., p. 228 (1876).

_Pithecia alba_, Schl., t. c. p. 229.

(_Plate XVI._)

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.

PLATE XVI.

{179}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. {180}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 {181}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.

Map of part of the basin of the Amazons to show the distribution of the Uakarí Monkeys. (Forbes, P. Z. S., 1880, p. 647.)

Supposed area of ''B. melanocephalus'', ''B. calvus'', and ''B. rubicundus'' shown by shading.]

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.

{182}"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. GENUS PITHECIA.

_Pithecia_, Geoffr., Ann. Mus., xix., p. 115 (1812).

_Chiropotes_, Gray, Cat. Monkeys Brit. Mus., p. 60 (1870), in part.

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.